全文获取类型
收费全文 | 3323篇 |
免费 | 33篇 |
国内免费 | 171篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 205篇 |
环保管理 | 289篇 |
综合类 | 590篇 |
基础理论 | 777篇 |
环境理论 | 2篇 |
污染及防治 | 1132篇 |
评价与监测 | 239篇 |
社会与环境 | 183篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 17篇 |
2022年 | 69篇 |
2021年 | 39篇 |
2020年 | 25篇 |
2019年 | 37篇 |
2018年 | 116篇 |
2017年 | 52篇 |
2016年 | 76篇 |
2015年 | 84篇 |
2014年 | 89篇 |
2013年 | 265篇 |
2012年 | 88篇 |
2011年 | 159篇 |
2010年 | 139篇 |
2009年 | 152篇 |
2008年 | 162篇 |
2007年 | 190篇 |
2006年 | 143篇 |
2005年 | 118篇 |
2004年 | 145篇 |
2003年 | 138篇 |
2002年 | 114篇 |
2001年 | 239篇 |
2000年 | 143篇 |
1999年 | 71篇 |
1998年 | 40篇 |
1997年 | 47篇 |
1996年 | 33篇 |
1995年 | 40篇 |
1994年 | 42篇 |
1993年 | 41篇 |
1992年 | 30篇 |
1991年 | 35篇 |
1990年 | 27篇 |
1989年 | 32篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 18篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 12篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有3527条查询结果,搜索用时 15 毫秒
561.
Chang BU Koh SM Kim YJ Seo JS Yoon YY Row JW Lee DM 《Journal of environmental radioactivity》2008,99(3):455-460
A Nationwide survey on the natural radioactivity in industrial raw mineral commodities (17 kinds of domestic and 18 kinds of imported) that are representative minerals used in production and consumption in South Korea was conducted. The target industrial minerals can be categorized into two groups. The first group covers non-metallic and metallic raw minerals with low levels of radioactivity such as clay, silica sand, carbonates, bituminous and anthracite coal, iron ores, ilmenite, rutile, and phosphate ore. The other group comprises minerals with high levels of radioactivity including zircon and monazite. One hundred and sixty-four domestic and imported samples were analysed by gamma-ray spectroscopy using an HPGe detector. The (40)K content ranges from <0.00131 to 2.69Bq g(-1), and (226)Ra and (232)Th range over <0.0006 to 0.630 and <0.0008 to 0.474Bq g(-1), respectively. There was no anthropogenic radioactive signal in any of the samples. 相似文献
562.
Vichot L Boyer C Boissieux T Losset Y Pierrat D 《Journal of environmental radioactivity》2008,99(10):1636-1643
In order to quantify tritium impact on the environmental, we studied vegetation continuously exposed to a tritiated atmosphere. We chose lichens as bio-indicators, trees for determination of past tritium releases of the Valduc Centre, and lettuce as edible vegetables for dose calculation regarding neighbourhood. The Pasquill and Doury models from the literature were tested to estimate tritium concentration in the air around vegetable for distance from the release point less than 500m. The results in tree rings show that organically bound tritium (OBT) concentration was strongly correlated with tritium releases. Using the GASCON model, the modelled variation of OBT concentration with distance was correlated with the measurements. Although lichens are recognized as bio-indicators, our experiments show that they were not convenient for environmental surveys because their age is not definitive. Thus, tritium integration time cannot be precisely determined. Furthermore, their biological metabolism is not well known and tritium concentration appears to be largely dependent on species. An average conversion rate of HTO to OBT was determined for lettuce of about 0.20-0.24%h(-1). Nevertheless, even if it is equivalent to values already published in the literature for other vegetation, we have shown that this conversion rate, established by weekly samples, varies by a factor of 10 during the different stages of lettuce development, and that its variation is linked to the biomass derivative. 相似文献
563.
Yu Sun Susanna T. Y. Tong Mao Fang Y. Jeffrey Yang 《Environment, Development and Sustainability》2013,15(6):1495-1515
The Las Vegas Valley metropolitan area is one of the fastest growing areas in the southwestern United States. The rapid urbanization has presented many environmental challenges. For instance, as population growth and urbanization continue, the supply of sufficient clean water will become a concern. In addition, the area is also experiencing the longest drought in history, and the volume of water storage in Lake Mead, the main fresh water supply for the entire region, has been reduced greatly. The water quality in the main stem of the Las Vegas Wash (LVW) and Lake Mead may also be significantly affected. In order to develop effective sustainable management plans, the very first step is to predict the plausible future urbanization and land use patterns. This paper presents an approach to predict the future land use pattern at the LVW watershed using a Markov cellular automata model. The multi-criteria evaluation was used to couple population density as a variable depicting the driving force of urbanization in the model. Moreover, landscape metrics were used to analyze land use changes in order to better understand the dynamics of urban development in the LVW watershed. The predicted future land use maps for the years 2030 and 2050 show substantial urban development in the area, much of which are located in areas sensitive to source water protections. The results of the analysis provide valuable information for local planners and policy makers, assisting their efforts in constructing alternative sustainable urban development schemes and environmental management strategies. 相似文献
564.
Roads function as prime habitats and corridors for invasive plant species. Yet despite the diversity of road types, there
is little research on the influence of these types on the spread of invaders. Common ragweed (Ambrosia artemisiifolia), a plant producing large amounts of allergenic pollen, was selected as a species model for examining the impact of road
type on the spread of invasive plants. We examined this relationship in an agricultural region of Quebec, Canada. We mapped
plant distribution along different road types, and constructed a model of species presence. Common ragweed was found in almost
all sampling sites located along regional (97%) and local paved (81%) roads. However, verges of unpaved local roads were rarely
(13%) colonized by the plant. A model (53% of variance explained), constructed with only four variables (paved regional roads,
paved local roads, recently mown road verges, forest cover), correctly predicted (success rate: 89%) the spatial distribution
of common ragweed. Results support the hypothesis that attributes associated with paved roads strongly favour the spread of
an opportunistic invasive plant species. Specifically, larger verges and greater disturbance associated with higher traffic
volume create propitious conditions for common ragweed. To date, emphasis has been placed on controlling the plant in agricultural
fields, even though roadsides are probably a much larger seed source. Strategies for controlling the weed along roads have
only focused on major highways, even though the considerable populations along local roads also contribute to the production
of pollen. Management prioritizations developed to control common ragweed are thus questionable. 相似文献
565.
Green shipping practices in the shipping industry: Conceptualization, adoption, and implications 总被引:1,自引:0,他引:1
Kee-Hung Lai Venus Y.H. LunChristina W.Y. Wong T.C.E. Cheng 《Resources, Conservation and Recycling》2011,55(6):631-638
There have been increasing concerns about the adverse impacts on the environment caused by cargo movement in international trade. Different stakeholders ranging from shippers and carriers to government bodies and international communities have expressed worries about the environmental impacts brought by shipping related activities. The pollution and waste created in the shipping processes have imposed environmental burdens and accelerated resource depletion. The situation is set to worsen in the face of intensifying trade globalization, which has contributed to sustained growth in international shipping activities. To help protect the environment, many shipping firms have taken the initiative to find ways to lessen the environmental damage of their operations while enhancing their performance. The objective of this study is to examine the environmental awareness and the environmental measures taken in the shipping industry. We propose a conceptual framework for evaluating green shipping practices and develop several propositions stating the conditions under which shipping firms would behave in an environmentally responsible manner. We conclude with managerial and policy implications of the conceptual framework to promote green shipping practices in the shipping industry. 相似文献
566.
Plant species with generalized dispersal mutualisms are considered to be robust to local frugivore extinctions because of redundancy between dispersal agents. However, real redundancy can only occur if frugivores have similar foraging and ranging patterns and if fruit is a limiting resource. We evaluated the quantitative and qualitative contributions of seed dispersers for an endochorus mast-fruiting species, Prunus javanica (Rosaceae) in Khao Yai National Park, Thailand, to evaluate the potential redundancy of dispersers. Data were collected from tree watches, seed/fruit traps, and seed transects under and away from fruiting trees, feeding and seed deposition by gibbons (Hylobates lar), and evaluations of seed and first-year seedling survival. We identified three clusters of dispersers within the network. Most (>80%) frugivore species observed were small birds and squirrels that were not functional dispersers, dropping most seeds under or very near the tree crown, where seedling survival was ultimately nil. Monkeys (Macaca leonina) were low-quality, short-range dispersers, but they dispersed large numbers of seeds and were responsible for 67% of surviving first-year seedlings. Gibbons and Oriental Pied Hornbills (Anthracoceros albirostris) handled few fruits, but they provided the highest quality service by carrying most seeds away from the canopy to medium and long distances, respectively. Although there was overlap in the deposition patterns of the functional dispersers, they displayed complementary, rather than redundant, roles in seed dispersal. Satiation of all functional dispersers further limited their capacity to "replace" one another. Redundancy must be evaluated at the community level because each type of disperser may shift to different species in the non-masting years of P. javanica. Our results underscore the need for research on broader spatial and temporal scales, which combines studies of dispersal and plant recruitment, to better understand mechanisms that maintain network stability. 相似文献
567.
As a major ecosystem type, wetland provides invaluable ecological services. Environmental pollution, especially pesticides pollution should be paid more attention to keep wetlands healthy. Based on the risk quotient method, coupled with a probabilistic risk assessment model, this paper proposed a methodology suitable for ecological risk assessment of pesticide residues for wetland ecosystems. As an important industrializing and ecologically vulnerable area in China, the Taihu Lake wetland was chosen for the case study. The risks of eight pesticides in Taihu Lake wetland were assessed, as single substances and in mixtures. The assessment indicates that risks of the representative species are not significant. In general, the herbicide is found to be more toxic for algae, whereas insecticides pose more risks to zooplankton, insect and fish. For each pesticide in the wetland, the ecological risk it poses is acceptable. But the combined ecological risk posed by mixture can harm more than 10% of species of the wetland ecosystem, mainly dominated by dichlorvos, dimethoate and malathion contributions. These results imply that pesticide residues have been posing pressures on the ecosystem of the Taihu Lake wetland. It is recommended that proper countermeasures should be implemented to reduce the risks. 相似文献
568.
A method that allows the estimation of the thermodynamic parameters of the biosphere has been developed. It results in the subdivision of the following four phase states of the biosphere: three equilibrium states: “white planet” with high albedo and low entropy; temperate forest in winter with high entropy; and desert with high entropy; and one nonequilibrium state: the “active forests” with low entropy, high information gain and the highest exergy values. The phase shift to a nonequilibrium state happens when albedo is less than 0.2. 相似文献
569.
Bandara JM Wijewardena HV Bandara YM Jayasooriya RG Rajapaksha H 《Environmental geochemistry and health》2011,33(5):439-453
Chronic renal failure (CRF) associated with elevated dietary cadmium (Cd) among farming communities in the irrigated agricultural area under the River Mahaweli diversion scheme has reached a significantly higher level of 9,000 patients. Cadmium, derived from contaminated phosphate fertilizer, in irrigation water finds its way into reservoirs, and finally to food, causing chronic renal failure among consumers. Water samples of River Mahaweli and its tributaries in the upper catchment were analyzed to assess the total cadmium contamination of river water and the possible source of cadmium. Except a single tributary (Ulapane Stream, 3.9?μg?Cd/l), all other tested tributaries carried more than 5?μg?Cd/l, the maximum concentration level accepted to be safe in drinking water. Seven medium-sized streams carrying surface runoff from tea estates had 5.1-10?μg?Cd/l. Twenty larger tributaries (Oya), where the catchment is under vegetable and home garden cultivation, carried 10.1-15?μg?Cd/l. Nine other major tributaries had extremely high levels of Cd, reaching 20?μg?Cd/l. Using geographic information system (GIS), the area in the catchment of each tributary was studied. The specific cropping system in each watershed was determined. The total cadmium loading from each crop area was estimated using the rates and types of phosphate fertilizer used by the respective farmers and the amount of cadmium contained in each type of fertilizer used. Eppawala rock phosphate (ERP), which is mostly used in tea estates, caused least pollution. The amount of cadmium in tributaries had a significant positive correlation with the cadmium loading of the cropping system. Dimbula Tea Estate Stream had the lowest Cd loading (495.9?g/ha/year), compared with vegetable-growing areas in Uma Oya catchment with 50,852.5?g?Cd/ha/year. Kendall's τ rank correlation value of total Cd loading from the catchment by phosphate fertilizer used in all crops in the catchment to the Cd content in the tributaries was +0.48. This indicated a major contribution by the cropping system in the upper catchment area of River Mahaweli to the eventual Cd pollution of river water. Low soil pH (4.5-5.2), higher organic matter content (2-3%), and 18-20?cmol/kg cation exchange capacity (CEC) in upcountry soil have a cumulative effect in the easy release of Cd from soil with the heavy surface runoff in the upcountry wet zone. In view of the existing water conveyance system from upcountry to reservoirs in North Central Province (NCP) through diversion of River Mahaweli, in addition to their own nonpoint pollution by triple superphosphate fertilizer (TSP), this demands a change in overall upper catchment management to minimize Cd pollution through agriculture inputs to prevent CRF due to elevated dietary cadmium among NCP farmers. 相似文献
570.
J.X. Wen A. HeidariS. Ferraris V.H.Y. Tam 《Journal of Loss Prevention in the Process Industries》2011,24(2):187-193
A modelling strategy has been developed for consequence analysis of medium and large scale gaseous detonation. The model is based on the solution of Euler equations with one-step chemistry. The Van Leer flux limited method which is a total variation diminishing scheme is used for shock capturing. Preliminary calculations were firstly conducted for small domains with fine grids which resolve the wave, relatively coarse grids which have less than 10 grids across the wave and coarse grids in which the minimum grid size is larger than the wave thickness to ensure that the reaction scheme has been properly tuned to capture the correct detonation pressure, temperature and velocity in the resolutions used in the different cases. The model was firstly tested against a medium scale detonation test in a shock tube with U-bends. Reasonably good agreement is achieved on detonation pressure and mean shock wave velocities at different measuring segments of the tube. Following the validation, the detonation of a hypothetical planar propane-air cloud is simulated. The predictions uncovered some interesting features of such large scale detonation phenomena which are of significance in the safety context, especially for accidental investigations. The findings from the present analysis are in line with the forensic evidence on damages in some historic accidents and challenges previous analysis of a major accident in which forensic evidence suggested localised detonation but was considered as the consequence of fire storms by the investigation team. 相似文献