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991.
M R Taylor  P T Harrison 《Chemosphere》1999,39(8):1237-1248
An overview is presented of the main evidence for endocrine disruption in wildlife, focusing on reproductive effects. While there are a few clear examples of endocrine disruptive effects resulting from environmental chemical exposure, in most cases a causal link between the observed abnormalities and chemical exposure has not been established. In other cases there appears to be a link but the specific chemicals responsible for the observed effects, and the mechanisms involved, remain to be elucidated. Also it is largely unknown whether or not observed changes in individual animals lead to population-level effects. Priority research projects for the UK, ultimately aimed at determining the population-level significance of endocrine disruption, are described.  相似文献   
992.
The preparation and dissemination of policy statements are necessary but insufficient to prevent the inappropriate use of infant-feeding products in emergencies. The widespread failure of humanitarian agencies operating in the Balkan crisis to act in accordance with international policies and recommendations provides a recent example of the failure to translate infant-feeding policies into practice. This article explores the underlying reasons behind the failures which include: (1) the weak institutionalisation of policies; (2) the massive quantities of unsolicited donations of infant-feeding products: (3) the absence of monitoring systems; (4) inadequate co-ordination mechanisms; (5) the high costs of correcting mistakes; and (6) the cumulative effects of poor practice. Efforts to uphold best practice during the crisis are also documented. Finally, the article identifies actions that could be undertaken in advance of and during future emergencies to enhance the application of infant feeding policies in emergencies.  相似文献   
993.
Abstract: Modern conservation biologists may reap great insight from neglected documents prepared by field biologists of the past. Three U.S. National Park Service field biologists of the 1920s and 1930s, George Wright, Ben Thompson, and Joseph Dixon, collaborated on the first field faunal survey of U.S. national parks. The results, Fauna 1 and Fauna 2 , were published in 1933 and 1935, respectively. In addition to information about the status of park vertebrates, these monographs produced the first comprehensive list of ecologically based policies for the U.S. National Park System. They also contained precursors of many of the ideas now considered basic to conservation biology. Today's conservation biologists seem unaware of the work of these three researchers. Contemporary biologists tend to think of the key concepts in conservation biology as having developed after the 1970s, but Wright, Thompson, and Dixon expressed in rough form many of these concepts half a century before. They combined their ideas with those of their predecessors and mentors to produce an unprecedented, easy-to-understand guide on managing the biotic resources of the national parks. Despite the efforts of these pioneers, their guidance did not contribute to a significant reshaping of park management practice for at least three decades.  相似文献   
994.
The Application of IUCN Red List Criteria at Regional Levels   总被引:13,自引:1,他引:12  
This paper represents a work in progress by the World Conservation Union (IUCN). Earlier drafts of the work have appeared in IUCN publications, but the "International Issues" section of Conservation Biology seems an appropriate and important place to publish the penultimate version of the document. Comments on this issue in general or on the approach taken by the IUCN should be sent to the authors directly.
Joshua Ginsburg  相似文献   
995.
Atmospheric deposition of trace metals and metalloids from anthropogenic sources has led to the contamination of many European peatlands. To assess the fate and behaviour of previously deposited arsenic and lead, we constructed catchment-scale mass budgets for a degraded peatland in Northern England. Our results show a large net export of both lead and arsenic via runoff (282 ± 21.3 gPb ha(-1) y(-1) and 60.4 ± 10.5 gAs ha(-1) y(-1)), but contrasting controls on this release. Suspended particulates account for the majority of lead export, whereas the aqueous phase dominates arsenic export. Lead release is driven by geomorphological processes and is a primary effect of erosion. Arsenic release is driven by the formation of a redox-dynamic zone in the peat associated with water table drawdown, a secondary effect of gully erosion. Degradation of peatland environments by natural and anthropogenic processes has the potential to release the accumulated pool of legacy contaminants to surface waters.  相似文献   
996.
Callaghan TV  Tweedie CE  Webber PJ 《Ambio》2011,40(6):555-557
Polar and alpine environments are changing rapidly due to increases in temperature, which are amplified in the Arctic, as well as changes in many local factors. The impacts on ecosystems and their function have potential consequences for local residents and the global community. Tundra areas are vast and diverse, and the knowledge of geographical variation in environmental and ecosystem change is limited to relatively few locations, or to remote sensing approaches that are limited mostly to the past few decades. The International Polar Year, IPY, provided a context, stimulus and timely opportunities for re-visiting old research sites and data sets to collate data on past changes, to pass knowledge from old to new generations of researchers and to document environmental characteristics of sites to facilitate detection and attribution of future changes. Consequently, the project “Retrospective and Prospective Vegetation Change in the Polar Regions: Back to the Future,” BTF, was proposed and endorsed as an IPY activity (project #512). With national funding support, teams of researchers re-visited former sites and data sets throughout the Arctic and some alpine regions. These efforts have amounted to a gamut of “BTF” studies that are collectively geographically expansive and disciplinary diverse. A selection of these studies are introduced and presented in the current issue together with a brief synthesis of their findings.  相似文献   
997.
The increasing need for biomass for energy and feedstocks, along with the need to divert organic methane generating wastes from landfills, may provide the economic leverage necessary to return this type of marginal land to functional and economic use and is strongly supported by policy at the European Union (EU) level. The use of land to produce biomass for energy production or feedstocks for manufacturing processes (such as plastics and biofuels) has, however, become increasingly contentious, with a number of environmental, economic, and social concerns raised. The REJUVENATE project has developed a decision support framework to help land managers and other decision makers identify potential concerns related to sustainability and what types of biomass reuse for marginal land might be possible, given their particular circumstances. The decision‐making framework takes a holistic approach to decision making rather than viewing biomass production simply as an adjunct of a planned phytoremediation project. The framework is serviceable in Germany, Sweden, and the United Kingdom. These countries have substantive differences in their land and biomass reuse circumstances. However, all can make use of the set of common principles of crop, site, value, and project risk management set out by REJUVENATE. This implies that the framework should have wider applicability across the EU. This article introduces the decision support framework. © 2011 Wiley Periodicals, Inc.  相似文献   
998.
The rates of accumulation and subsequent loss of stable cesium (133Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of 133Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg−1 d−1 dry mass) and a loss rate parameter k (d−1) were estimated for each organism using time-series measurements of 133Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (Cr). The maximum 133Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The Cr based on dry mass for plankton and C. punctipennis were 1220 L kg−1 and 5570 L kg−1, respectively, and were less than the Cr of 8630 L kg−1 for periphyton and 47,700 L kg−1 for H. trivolvis. Although the Cr differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the Cr for the mostly nonpiscivorous L. macrochirus of 22,600 L kg−1 was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg−1. Although the Cr for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum 133Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides.  相似文献   
999.
Forest Health Monitoring in the United States: First Four Years   总被引:24,自引:0,他引:24  
To address the need for more effective methods for evaluating and assessing forest ecosystem health, the USDA-Forest Service and the US Environmental Protection Agency through its Environmental Monitoring and Assessment Program developed the Forest Health Monitoring program. The program was initiated in 1990 and by 1994 was present in the major areas of the United States. This paper presents an overview of the program, the indicators and methods developed for the program, and some of the results after four years of monitoring and research.  相似文献   
1000.
Hazard mitigation planners claim that foresighted present actions and investments produce significant future benefits. However, they have difficulty in supporting their claims, since previously their evidence typically was derived from individual case studies. Constituents and decision makers are often sceptical, believing that individual cases are either inapplicable to their situation or non-randomly selected to support a particular view. Planners need objective evidence based on a large body of experience to support the case for mitigation. Such is the unique contribution of a recent U.S. study that found that each dollar spent in three federal natural hazard mitigation grant programs (the Hazard Mitigation Grant Program, Project Impact, and the Flood Mitigation Assistance Program) saves society an average of $4 in future avoided losses. Complementing the aggregate benefit-cost analysis with community-based evaluations, the study yielded insights on how planners can improve long-term community resilience in the face of extreme events. Valuable lessons for mitigation planners and policy makers emerged: the need to consider a wide variety of losses, the importance of mixing qualitative with quantitative analysis, the value of averaging results over a large number of projects, and the need to more explicitly address social issues and data collection in order to reduce vulnerability and enhance resilience to cope with twenty-first century hazards.  相似文献   
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