全文获取类型
收费全文 | 390篇 |
免费 | 13篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 17篇 |
废物处理 | 7篇 |
环保管理 | 105篇 |
综合类 | 54篇 |
基础理论 | 96篇 |
污染及防治 | 87篇 |
评价与监测 | 27篇 |
社会与环境 | 15篇 |
灾害及防治 | 4篇 |
出版年
2022年 | 6篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 6篇 |
2017年 | 13篇 |
2016年 | 17篇 |
2015年 | 7篇 |
2014年 | 13篇 |
2013年 | 25篇 |
2012年 | 15篇 |
2011年 | 12篇 |
2010年 | 15篇 |
2009年 | 21篇 |
2008年 | 22篇 |
2007年 | 21篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 23篇 |
2002年 | 10篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有412条查询结果,搜索用时 15 毫秒
121.
Soil variability in watersheds accounts for the problem of partitioning downstream water quality data and evaluating sources of non-point pollution. This review of previous water quality studies was conducted to examine more closely the influence of soil properties on pollutant export. The approach used in this paper was to start with data from the two largest watersheds (Maumee and Sandusky) and then compare them on a unit area export basis with data from intermediate-size and smaller watersheds. General relationships between pollutant levels at the river mouth and upstream soil conditions are vague and seemingly contradictory at the large-watershed scale. With smaller watersheds, it can be determined that soil texture, slope, and internal drainage are controlling factors for pollutant export. Although Paulding (very-fine, illitic, nonacid, mesic Typic Epiaquept) and Roselms (very-fine, illitic, mesic Aeric Epiaqualf) soils occupy only 5% of the Maumee basin, they generate more than 10 times as much sediment per unit area as the tile-drained Hoytville (fine, illitic, mesic Mollic Epiaqualf) soils that occupy 16% of the Maumee basin. Tile drainage of very poorly drained soils that are formed from either glacial till or silty to sandy lake deposits reduces runoff and increases downward movement of soluble nutrients into tile drains. The assumption that sloping moraine areas are the primary source of pollutants should be reexamined based on this review. 相似文献
122.
Reliable QSAR for estimating Koc for persistent organic pollutants: correlation with molecular connectivity indices 总被引:2,自引:0,他引:2
Several recent studies have shown that n-octanol/water partition coefficients may not be a good predictor for estimating soil sorption coefficients of persistent organic pollutants (POPs), defined here as chemicals with log Kow greater than 5. Thus, an alternative QSAR model was developed that seems to provide reliable estimates for the soil sorption coefficients of persistent organic pollutants. This model is based on a set of calculated molecular connectivity indices and evaluated soil sorption data for 18 POPs. The chemical's size and shape, quantified by 1chi, 3chiC and 4chiC(v) indices, have a dominant effect on the soil sorption process of POPs. The developed QSAR model was rationalized in terms of potential hydrophobic interactions between persistent organic pollutants and soil organic matrix. Its high predictive power has been verified by an extensive internal and external validation procedure. 相似文献
123.
Virginia E. Villafañe Paul J. Janknegt Marco de Graaff Ronald J. W. Visser Willem H. van de Poll Anita G. J. Buma E. Walter Helbling 《Marine Biology》2008,154(6):1021-1029
During austral summer 2006, experiments were carried out to evaluate the effects of ultraviolet radiation (UVR, 280–400 nm)
on carbon fixation of natural phytoplankton assemblages from Patagonia (Argentina). Surface water samples were collected (ca.
100 m offshore) at mid morning using an acid-cleaned (1 N HCl) dark container. The short-term impact of UVR (measured as radiocarbon
incorporation) was immediately assessed by exposing samples to three artificial illumination treatments: PAR (400–700 nm),
PAR + UV-A (320–700 nm), and PAR + UV-A + UV-B (280–700 nm). Pico-nanoplankton characterized the assemblages, and taxon-specific
pigment fingerprinting combined with CHEMTAX and supplemented with microscopic observations showed varied proportions of diatoms,
chlorophytes, and cyanobacteria throughout January–February 2006. Photosynthetic efficiency, as assessed through assimilation
numbers, was high [between 4.4 and 10.4 μg C (μg chl-a)−1 h−1], and it was probably favored by the supply of inorganic nutrients from the Chubut River. UVR-induced photoinhibition appeared
to be related to the taxonomic composition: in general, higher photoinhibition was observed when diatoms dominated, whereas
this was lower when samples were dominated by chlorophytes. Our data suggest that xanthophyll pigments might have provided
only limited protection in these already highlighted acclimated assemblages. 相似文献
124.
Given the growing popularity of indicators among policy-makers to measure progress toward conservation and sustainability goals, there is an urgent need to develop indicators that can be used accurately by both specialists and nonspecialists, drawing from the knowledge possessed by each group. This paper uses a case study from the Kalahari, Botswana to show how participatory and ecological methods can be combined to develop robust indicators that are accessible to a range of users to monitor and enhance the sustainability of land management. First, potential environmental sustainability indicators were elicited from pastoralists in three study sites. This knowledge was then evaluated by pastoralists, before being tested empirically using ecological and soil-based techniques. Despite the wealth of local knowledge about indicators, this knowledge was thinly spread. The knowledge was more holistic than published indicator lists for monitoring rangelands, encompassing vegetation, soil, livestock, wild animal, and socioeconomic indicators. Pastoralist preferences for vegetation and livestock indicators match recent shifts in ecological theory suggesting that livestock populations reach equilibrium with key forage resources in semiarid environments. Although most indicators suggested by pastoralists were validated through empirical work (e.g., decreased grass cover and soil organic matter content, and increased abundance of Acacia mellifera and thatching grass), they were not always sufficiently accurate or reliable for objective degradation assessment, showing that local knowledge cannot be accepted unquestioningly. We suggest that, by combining participatory and ecological approaches, it is possible to derive more accurate and relevant indicators than either approach could achieve alone. 相似文献
125.
A health risk assessment for fluoride in Central Europe 总被引:4,自引:0,他引:4
Fordyce FM Vrana K Zhovinsky E Povoroznuk V Toth G Hope BC Iljinsky U Baker J 《Environmental geochemistry and health》2007,29(2):83-102
Like many elements, fluorine (which generally occurs in nature as fluoride) is beneficial to human health in trace amounts,
but can be toxic in excess. The links between low intakes of fluoride and dental protection are well known; however, fluoride
is a powerful calcium-seeking element and can interfere with the calcified structure of bones and teeth in the human body
at higher concentrations causing dental or skeletal fluorosis. One of the main exposure routes is via drinking water and the
World Health Organisation currently sets water quality guidelines for the element. In Central Europe, groundwater resources
that exceed the guideline value of 1.5 mg l−1 are widespread and effects on health of high fluoride in water have been reported. The aim of the current project was to
develop a geographic information system (GIS) to aid the identification of areas where high-fluoride waters and fluorosis
may be a problem; hence, where water treatment technologies should be targeted. The development of the GIS was based upon
the collation and digitisation of existing information relevant to fluoride risk in Ukraine, Moldova, Hungary and Slovakia
assembled for the first time in a readily accessible form. In addition, geochemistry and health studies to examine in more
detail the relationships between high-fluoride drinking waters and health effects in the population were carried out in Moldova
and Ukraine demonstrating dental fluorosis prevalence rates of 60–90% in adolescents consuming water containing 2–7 mg l−1 fluoride. 相似文献
126.
Profiling unauthorized natural resource users for better targeting of conservation interventions
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mariel Harrison Julia Baker Medard Twinamatsiko E.J. Milner‐Gulland 《Conservation biology》2015,29(6):1636-1646
Unauthorized use of natural resources is a key threat to many protected areas. Approaches to reducing this threat include law enforcement and integrated conservation and development (ICD) projects, but for such ICDs to be targeted effectively, it is important to understand who is illegally using which natural resources and why. The nature of unauthorized behavior makes it difficult to ascertain this information through direct questioning. Bwindi Impenetrable National Park, Uganda, has many ICD projects, including authorizing some local people to use certain nontimber forest resources from the park. However, despite over 25 years of ICD, unauthorized resource use continues. We used household surveys, indirect questioning (unmatched count technique), and focus group discussions to generate profiles of authorized and unauthorized resource users and to explore motivations for unauthorized activity. Overall, unauthorized resource use was most common among people from poor households who lived closest to the park boundary and farthest from roads and trading centers. Other motivations for unauthorized resource use included crop raiding by wild animals, inequity of revenue sharing, and lack of employment, factors that created resentment among the poorest communities. In some communities, benefits obtained from ICD were reported to be the greatest deterrents against unauthorized activity, although law enforcement ranked highest overall. Despite the sensitive nature of exploring unauthorized resource use, management‐relevant insights into the profiles and motivations of unauthorized resource users can be gained from a combination of survey techniques, as adopted here. To reduce unauthorized activity at Bwindi, we suggest ICD benefit the poorest people living in remote areas and near the park boundary by providing affordable alternative sources of forest products and addressing crop raiding. To prevent resentment from driving further unauthorized activity, ICDs should be managed transparently and equitably. 相似文献
127.
128.
Jarvie HP Neal C Withers PJ Baker DB Richards RP Sharpley AN 《Journal of environmental quality》2011,40(2):492-504
Extended end-member mixing analysis (E-EMMA) is presented as a novel empirical method for exploring phosphorus (P) retention and release in rivers and watersheds, as an aid to water-quality management. E-EMMA offers a simple and versatile tool that relies solely on routinely measured P concentration and flow data. E-EMMA was applied to two river systems: the Thames (U.K.) and Sandusky River (U.S.), which drain similar watershed areas but have contrasting dominant P sources and hydrology. For both the Thames and Sandusky, P fluxes at the watershed outlets were strongly influenced by processes that retain and cycle P. However, patterns of P retention were markedly different for the two rivers, linked to differences in P sources and speciation, hydrology and land use. On an annual timescale, up to 48% of the P flux was retained for the Sandusky and up to 14% for the Thames. Under ecologically critical low-flow periods, up to 93% of the P flux was retained for the Sandusky and up to 42% for the Thames. In the main River Thames and the Sandusky River, in-stream processes under low flows were capable of regulating the delivery of P and modifying the timing of delivery in a way that may help to reduce ecological impacts to downstream river reaches, by reducing ambient P concentrations at times of greatest river eutrophication risk. The results also suggest that by moving toward cleaner rivers and improved ecosystem health, the efficiency of P retention may actually increase. 相似文献
129.
E. L. Carroll N. J. Patenaude S. J. Childerhouse S. D. Kraus R. M. Fewster C. S. Baker 《Marine Biology》2011,158(11):2565-2575
The abundance of New Zealand subantarctic southern right whales (Eubalaena australis) was estimated for the first time using mark-recapture methods based on photo-identification and microsatellite genotyping
(13 loci). Individual identification photographs of 383 whales and microsatellite genotypes of 235 whales were collected during
annual austral winter field surveys from 1995 to 1998. Given the 4-year survey period and lack of geographic and demographic
closure, we estimated super-population abundance using the POPAN Jolly-Seber model implemented in the software programme MARK.
Models with constant survivorship but time-varying capture probability and probability of entry into the population were the
most suitable due to the survey design. This provided estimates of abundance in 1998 of 908 non-calf whales (95% C.L. = 755,
1,123) for the photo-identification and 910 non-calf whales (95% C.L. = 641, 1,354) for the microsatellite genotype data sets.
The current estimate of 900 whales may represent less than 5% of the pre-whaling abundance in New Zealand waters. 相似文献
130.
Craig F. Aumack Charles D. Amsler James B. McClintock Bill J. Baker 《Marine Biology》2011,158(8):1879-1885
Amphipods along the western Antarctic Peninsula appear to gain refuge from predators by associating with chemically defended
macroalgae rather than palatable macroalgae. However, nothing is known about amphipod activity at night. If foraging on non-chemically
defended macroalgae regularly occurs, then nocturnal foraging seems beneficial since visual predators are disadvantaged. To
test this hypothesis, we collected three common macroalgal species and affiliated mesograzers, approximately 3 h before and
after sunset. All associated mesofauna were counted and densities recorded. Amphipod densities were significantly decreased
during the night on the chemically defended Desmarestia menziesii, while significantly increased on the palatable Iridaea cordata. Additionally, the amphipod Gondogeneia antarctica was found in significantly higher densities at night on Palmaria decipiens, a species shown to be readily eaten by G. antarctica and omnivorous fish. We believe that chemically defended macroalgae act as a refuge for mesograzers during the day, while
more widespread foraging occurs at night. 相似文献