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991.
Distinguishing and quantifying anthropogenic trace metals and phosphorus accumulated in sediment is important for the protection
of our aquatic ecosystems. Here, anthropogenic proportion and potential sources of trace metals and phosphorus in surface
sediments of Chaohu Lake were evaluated based on the exhaustive geochemical data. The analysis shows that concentrations of
major and trace metals, and phosphorus, displayed significant spatial diversity and almost all elements were over the pre-industrial
background value, which should be related to the variations of sediment composition partially. Therefore, conservative element
normalization was introduced and calculated enrichment factors (EFs) of the elements were referenced highlighting the human
contamination. EFs of the major and trace metals, except Zn, Pb, and Cu, were all nearly 1.0, indicating the detrital origin.
The EFs of Zn, Pb, Cu and phosphorus were 1.0–10.4, 1.0–3.8, 1.0–4.9, and 1.0–7.6, respectively, showing moderate to significant
contamination. Higher EFs of Zn, Pb and Cu occurred in the mouth areas of Nanfei River and Zhegao River, and they decreased
to the lake center in the northwest and northeast lake areas, respectively. We deduced that anthropogenic Zn, Pb, and Cu were
mainly from urban and industrial point sources and the non-point sources of atmospheric deposition contributed little to their
contamination. The EFs of phosphorus showed similar spatial degradation with that of Zn, Pb, and Cu. Moreover, higher EFs
(>1) of phosphorus also occurred in other areas adjacent to the river mouths besides Nanfei River and Zhegao River. This indicated
that the non-point agricultural source may also be responsible for the contamination of phosphorus in Chaohu Lake in addition
to the urban sewage sources. Anthropogenic phosphorus was mainly concentrated in the speciation of NaOH-P, which had higher
potential biological effects than the detrital proportion. Concentrations of Zn, Pb and Cu surpassed the threshold effect
concentrations (TEC) of consensus-based sediment quality guidelines of freshwater ecosystems, especially in the contaminated
northwest area of Chaohu Lake. This highlighted the contributions of anthropogenic contamination to the elevated potential
biological effects of trace metals. Though there had been no obvious human contamination of Cr and Ni in Chaohu Lake, concentrations
were all over the TECs, which may be due to higher background levels in the parent materials of soils and bedrocks in Chaohu
Lake catchment. 相似文献
992.
The paper presents new studies about the removal efficiencies and characterization of the Municipal Wastewater Treatment Plant (MWWTP) in Kayseri, Turkey, which is serving for 800,000 population equivalents with the capacity of 110,000 m(3)/day, between 2006 and 2009. Kayseri discharges its effluents to Karasu Creek that downstream joins the Kizilirmak river, the longest river in Turkey discharging into the Black Sea. Four years of operation data between 2006 and 2009 calendar years were obtained from KASKI General Directorate. Influent and effluent samples were collected daily and suspended solids (SS), chemical oxygen demand (COD), biochemical oxygen demand in 5 days (BOD(5)), total nitrogen (TN), and total phosphorus (TP) were measured, aiming to study the evolution of the removal efficiencies for each year. The following yearly mean removal efficiencies were performed in the treatment plant: 94%, 97%, 97%, 95% for SS; 94%, 96%, 95%, 95% for COD; 98%, 98%, 98%, 98% for BOD(5); 84%, 87%, 89%, 82% for TN; and 71%, 86%, 80%, 86% for TP, in 2006, 2007, 2008, and 2009, respectively. The performance of Kayseri MWWTP was given both in terms of influent and effluent quality and in comparison with the current legislation on discharge limits to the receiving body. During the studied period, mean concentrations in the effluent did not exceed the imposed limits, but sometimes, higher values were noticed for SS, TN, and TP. In conclusion, the plant performances concerning these parameters were excellent and Kayseri MWWTP was operating efficiently according to the conventional control parameters. 相似文献
993.
Quantifying the Effects of Conservation Practices on Soil,Water, and Nutrients in the Loess Mesa Ravine Region of the Loess Plateau,China 总被引:1,自引:0,他引:1
A large number of soil and water conservation programs have been implemented on the Loess Plateau of China since the 1950s.
To comprehensively assess the merits and demerits of the conservation practices is of great importance in further supervising
the conservation strategy for the Loess Plateau. This study calculates the impact factors of conservation practices on soil,
water, and nutrients during the period 1954–2004 in the Nanxiaohegou Catchment, a representative catchment in the Loess Mesa
Ravine Region of the Loess Plateau, China. Brief conclusions could be drawn as follows: (1) Soil erosion and nutrient loss
had been greatly mitigated through various conservation practices. About half of the total transported water and 94.8 % of
the total transported soil and nutrients, had been locally retained in the selected catchment. The soil retained from small
watersheds do not only form large-scale fertile farmland but also safeguard the Yellow River against overflow. (2) Check dam
was the most appropriate conservation practice on the Loess Plateau. In the selected catchment, more than 90 % of the retained
soil and water were accomplished by the dam farmland, although the dam farmland occupied only 2.3 % of the total area of all
conservation measures. Retention abilities of the characteristic conservation practices were in the following order: dam farmland > terrace
farmland > forest land and grassland. (3) The conservation practices were more powerful in retaining sediment than in reducing
runoff from the Loess Plateau, and the negative effects of the conservation practices on reducing water to the Yellow River
were relatively slight. 相似文献
994.
Alves RR Vieira KS Santana GG Vieira WL Almeida WO Souto WM Montenegro PF Pezzuti JC 《Environmental monitoring and assessment》2012,184(11):6877-6901
For many millennia humans and reptiles have interacted, but the attitude of humans towards these animals has depended on culture, environment, and personal experience. At least 719 reptile species are known to occur in Brazil and about 11% of this fauna has been exploited for many different purposes, including bushmeat, leather, ornamental and magic/religious uses, and as folk medicines. Brazil can therefore serve as an interesting case study for better understanding reptile use by human societies, and the present paper catalogues some of the reptile species being used in Brazil and discusses implications for their conservation. A literature review indicated that 81 reptile species are culturally important in this country, with 47 (58%) species having multiple uses, 54 being used for medicinal purposes, 38 as food, 28 for ornamental or decorative purposes, 20 used in magic/religious practices, 18 as pets, and 40 are commonly killed when they come into contact with humans. Regarding their conservation status, 30 (37.5%) are included on State's Red List, Brazilian Red List or the IUCN Red List. There are many forms of interaction between reptiles and humans in Brazil-although most of them are quite negative in terms of wildlife conservation-which reinforces the importance of understanding such uses and interactions in the context of protecting reptiles in Brazil. A better understanding of the cultural, social, and traditional roles of these reptiles is fundamental to establishing management plans for their sustainable use. 相似文献
995.
Assessment of groundwater vulnerability in the Yinchuan Plain,Northwest China using OREADIC 总被引:13,自引:0,他引:13
Groundwater vulnerability assessments provide a measure of the sensitivity of groundwater quality to an imposed contaminant
load and are globally recognized as an essential element of all aquifer management and protection plans. In this paper, the
vulnerability of groundwaters underlying the Yinchuan Plain of Northwest China is determined using OREADIC, a GIS-based assessment
tool that incorporates the key characteristics of the universally popular DRASTIC approach to vulnerability assessment but
has been modified to consider important additional hydrogeological factors that are specific to the region. The results show
that areas of high vulnerability are distributed mainly around Qingtongxia City, Wuzhong City, Lingwu City, and Yongning County
and are associated with high rates of aquifer recharge, shallow depths to the water table, and highly permeable aquifer materials.
The presence of elevated NO3− in the high vulnerability areas endorses the OREADIC approach. The vulnerability maps developed in this study have become
valuable tools for environmental planning in the region and will be used for predictive management of the groundwater resource. 相似文献
996.
Cornelia Hesse Valentina Krysanova Anja Vo? 《Environmental Modeling and Assessment》2012,17(6):589-611
For a long time, watershed models focused on the transport of chemicals from the terrestrial part of the watershed to the surface water bodies by leaching and erosion. After the substances had reached the surface water, they were routed through the channel network often without any further transformation. Today, there is a need to extend watershed models with in-stream processes to bring them closer to natural conditions and to enhance their usability as support tools for water management and water quality policies. This paper presents experience with implementing in-stream processes in a ecohydrological dynamic watershed model and its application on the large scale in the Saale River basin in Germany. Results demonstrate that new implemented water quality parameters like chlorophyll a concentrations or oxygen amount in the reach can be reproduced quite well, although the model results, compared with results achieved without taking into account algal and transformation processes in the river, show obvious improvement only for some of the examined nutrients. Finally, some climate and water management scenarios expected to impact in-stream processes in the Saale basin were run. Their results illustrate the relative importance of physical boundary conditions on the amount and concentration of the phytoplankton, which leads to the conclusion that measures to improve water quality should not only take nutrient inputs into account but also climate influences and river morphology. 相似文献
997.
Hg transfer from contaminated soils to plants and animals 总被引:1,自引:0,他引:1
S. M. Rodrigues B. Henriques A. T. Reis A. C. Duarte E. Pereira P. F. A. M. R?mkens 《Environmental Chemistry Letters》2012,10(1):61-67
Understanding the transfer of mercury (Hg) from soil to crops is crucial due to Hg toxicity and Hg occurrence in terrestrial
systems. Previous research has shown that available Hg in soils contributes to plant Hg levels. Plant Hg concentrations are
related to soil conditions and plant characteristics. Mechanistic models describing such soil–plant interactions are however
difficult to quantify. Here we performed a field study in agricultural, mining and industrial areas in Portugal to evaluate
potential food chain risks. The uptake of Hg by Italian ryegrass, ryegrass, orchard grass, collard greens and rye was measured
to calculate daily intakes (DI) of Hg for cows and sheep grazing. A total of 136 soil samples and 129 plant samples were analysed.
Results show that total Hg concentrations ranged from 0.01 to 98 mg kg−1 in soils; 0.01–5.4 mg kg−1 in shoots and 0.01–42 mg kg−1 in roots. Calculated DI ranged from 0.18 to 132 mg d−1 for cows, and from 0.028 to 23 mg d−1 for sheep. In 27 grassland sites, daily intakes exceeded the acceptable daily intake of both cows and sheep in view of food
safety considering Hg in animal kidneys evidencing potential risks to human health. The transfer of Hg from soil to crops
was described using empirical Freundlich-type functions. For ryegrass, orchard grass and collard greens, the soil-to-root
or soil-to-shoot transfer of Hg appeared to be controlled by the total soil Hg concentration and levels of Alox and Feox. Empirical functions allowed us to obtain realistic estimates of Hg levels in crops and can be used as an alternative to
mechanistic models when evaluating food chain risks of Hg contamination in agricultural soils. 相似文献
998.
R.?RejaniEmail author K.?V.?Rao M.?Osman Ch.?Srinivasa Rao K.?Sammi?Reddy G.?R.?Chary Pushpanjali Josily?Samuel 《Environmental monitoring and assessment》2016,188(3):143
The ungauged wet semi-arid watershed cluster, Seethagondi, lies in the Adilabad district of Telangana in India and is prone to severe erosion and water scarcity. The runoff and soil loss data at watershed, catchment, and field level are necessary for planning soil and water conservation interventions. In this study, an attempt was made to develop a spatial soil loss estimation model for Seethagondi cluster using RUSLE coupled with ARCGIS and was used to estimate the soil loss spatially and temporally. The daily rainfall data of Aphrodite for the period from 1951 to 2007 was used, and the annual rainfall varied from 508 to 1351 mm with a mean annual rainfall of 950 mm and a mean erosivity of 6789 MJ mm ha?1 h?1 year?1. Considerable variation in land use land cover especially in crop land and fallow land was observed during normal and drought years, and corresponding variation in the erosivity, C factor, and soil loss was also noted. The mean value of C factor derived from NDVI for crop land was 0.42 and 0.22 in normal year and drought years, respectively. The topography is undulating and major portion of the cluster has slope less than 10°, and 85.3 % of the cluster has soil loss below 20 t ha?1 year?1. The soil loss from crop land varied from 2.9 to 3.6 t ha?1 year?1 in low rainfall years to 31.8 to 34.7 t ha?1 year?1 in high rainfall years with a mean annual soil loss of 12.2 t ha?1 year?1. The soil loss from crop land was higher in the month of August with an annual soil loss of 13.1 and 2.9 t ha?1 year?1 in normal and drought year, respectively. Based on the soil loss in a normal year, the interventions recommended for 85.3 % of area of the watershed includes agronomic measures such as contour cultivation, graded bunds, strip cropping, mixed cropping, crop rotations, mulching, summer plowing, vegetative bunds, agri-horticultural system, and management practices such as broad bed furrow, raised sunken beds, and harvesting available water using farm ponds and percolation tanks. This methodology can be adopted for estimating the soil loss from similar ungauged watersheds with deficient data and for planning suitable soil and water conservation interventions for the sustainable management of the watersheds. 相似文献
999.
Kristian H?yer Toft 《Journal of Agricultural and Environmental Ethics》2012,25(2):223-237
Proponents of using genetically modified (GM) crops and food in the developing world often claim that it is unjust not to
use GMOs (genetically modified organisms) to alleviate hunger and malnutrition in developing countries. In reply, the critics
of GMOs claim that while GMOs may be useful as a technological means to increase yields and crop quality, stable and efficient
institutions are required in order to provide the benefits from GMO technology. In this debate, the GMO proponents tend to
rely on a simple utilitarian type of calculus that highlights the benefits of GMOs to the poor, but that overlooks the complex
institutional requirements necessary for GMO production. The critics, recognizing the importance of institutional conditions,
focus primarily on the negative impacts of institutional deficiencies, thereby overlooking the basically Rawlsian claim that
institutions per se may generate claims to justice. This article investigates how GMOs might generate claims to global justice and what type
of justice is involved. The paper argues that the debate on GMOs and global justice can be categorized into three views, i.e.,
the cosmopolitan, the pluralist, and the sceptic. The cosmopolitan holds that GMOs can and should be used for alleviating
global hunger, whereas the sceptic rejects this course of action. I will argue here for a moderately cosmopolitan approach,
relying on the pluralist view of institutions and the need to exploit the benefits of GMOs. This argument rests on the premise
that global cooperation on GMO production provides the relevant basis for assessing the use of GMOs by the standard of global
distributive justice. 相似文献
1000.
Effects of Tourism and Topography on Vegetation Diversity in the Subalpine Meadows of the Dongling Mountains of Beijing,China 总被引:1,自引:0,他引:1
Subalpine meadows in the Dongling Mountains (located at E115o26′-115o40′, N40o00′-40o05′) of Beijing, China are important
for tourism and the provision of ecosystem services. However, because of poor management serious degradation has occurred
on these subalpine meadows. The aim of this paper is to present a quantitative analysis of effects of tourism disturbance
and topography on the status and diversity of montane meadow communities and to provide direction for improved management.
Sixty quadrats of 2 × 2 m2 along 10 transects were set up to collect data on site characteristics and vegetation status. The relationships between community
composition and structure, species diversity, and tourism disturbance and topographic variables were analyzed by multivariate
methods (TWINSPAN and CCA). The results showed that eight meadow communities were identified by TWINSPAN. Most of them were
seriously degraded. The first CCA axis identified an elevation and tourism disturbance intensity gradient, which illustrated
that tourism disturbance and elevation were most important factors influencing meadow types, composition and structure. Some
resistant species and response species to tourism disturbance were identified and can be used as indicator species of tourism
disturbance. Species richness, heterogeneity and evenness were closely related to tourism disturbance and elevation. It is
concluded that tourism disturbance must be controlled to enable grassland rehabilitation to occur in the meadows. Measures
of effective management of the meadows were discussed. 相似文献