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261.
Summary Actions during most of this decade concerning where and how to locate a repository for high-level commercial and defence nuclear wastes have been guided by the National Environmental Policy Act and the Nuclear Waste Policy Act of 1982. Issues of repository siting have been controversial, and in December 1987 Congress passed the Nuclear Waste Policy Amendments Act, which identified Yucca Mountain, Nevada, as the nation's first and only site to be characterized for a potential repository. This decision has generated understudied questions regarding the role of science and ethics derived from the mandates of the legislation and use of environmental impact methodology which is predicated upon a positivistic model of science. Because of the importance of choosing an acceptable repository site to protect humans and natural resources for thousands of years into the future, the broadest spectrum of views and in-depth critiques of the role of science in the repository program is required in order that understudied questions can be resolved.John Lemons is the Chairperson of the Department of Life Sciences at the University of New England and, the Editor-in-Chief of the journalThe Environmental Professional. He has authored numerous articles on nuclear waste management, pollution, and wilderness management.Donald Brown is the Director of the Bureau of Hazardous Sites and Superfund Enforcement for the Commonwealth of Pennsylvania, 221 North Second Street, 3rd Floor, Harrisburg, Pennsylvania 17101. He has published numerous papers on the interface between philosophy and science as it relates to public policy making on environmental issues.  相似文献   
262.
Changing land use in the tropics has resulted in vast areas of damaged and degraded lands where biodiversity has been reduced. The majority of research on biodiversity has been focused on population and community dynamics and has rarely considered the ecosystem processes that are intimately related. We present a framework for examining the effects of changes in biodiversity on ecosystem function in natural, managed, and damaged tropical forests. Using a whole-ecosystem approach, the framework identifies key nutrient and energy cycling processes and critical junctures or pathways, termed interfaces, where resources are concentrated and transferred between the biotic and abiotic components of the ecosystem. Processes occurring at these interfaces, and the organisms or attributes participating in these processes, exert a strong influence on ecosystem structure. We use examples from Puerto Rico, Southern China, Dominica, and Nicaragua to illustrate how the functional diversity framework can be applied to critically examine the effects of changes in biodiversity on ecosystem function, and the relative success or failure of rehabilitation strategies. The few available data suggest that functional diversity, and not just species richness, is important in maintaining the integrity of nutrient and energy fluxes. High species richness, however, may increase ecosystem resiliency following disturbance by increasing the number of alternative pathways for the flow of resources. We suggest ways in which the framework of functional diversity can be used to design research to examine the effects of changes in biodiversity on ecosystem processes and in the design and evaluation of ecosystem management and land rehabilitation projects in the tropics.  相似文献   
263.
Geological surveys worldwide are involved with research in support of sustainable mineral resource development.The socio-economic benefits to be derived from these activities, however, continue to raise organisational and government sector questions. Fundamental questions include whether or not the resources committed are appropriate and in economic balance with the total benefits to be derived. Another question concerns the degree to which such services should be funded by the community at large. These questions in turn raise important issues regarding the role and cost of geological surveys, the impact of their services, and how they should maximise community benefit from their activities and expertise. To assess the value of geoscientific information,standard valuation processes need to be modified. This paper reports on a methodology designed to quantify the 'worth' of programmes upgrading regional geoscientific infrastructure. An interdisciplinary approach is used to measure the impact of geoscientific information using quantitative resource assessment, computer-based mineral potential modelling, statistical analysis and risk quantification to model decision-processes and assess the impact of additional data. These modelling stages are used to address problems of complexity,uncertainty and credibility in the valuation of geoscientific data. A case study demonstrates the application of the methodology to generate a dollar value for current regional data upgrade programmes in the Geological Survey of Queensland. The results obtained are used for strategic planning of future data acquisition programmes aimed at supporting mineral resource management and stimulating effective exploration activity.  相似文献   
264.
A reliable method for the determination of amino acids, suitable for routine shipboard use, is presented. Using reverse-phase high-performance liquid chromatography with computer-controlled gradient elution optimization, the amino acids commonly found in sea-water were clearly resolved and determined at the picomole level. A procedure was also developed to enable repeat injections of sea water samples to be made without deterioration of column material or performance. Thus the analysis was made more operator-independent and consequently more suitable for use at sea.  相似文献   
265.
The use of antagonistic microorganisms to control fungal pathogens is very limited because very few of the species which showed potential under experimental conditions were successful in the field. To be commercially useful, organisms must be easy to propagate and introduce into the soil in sufficient numbers to affect the pathogen and the cost must be significantly less than the expected losses that would result from disease caused by the pathogen.Fungi are more able to grow in soils of low moisture content than bacteria and under such conditions bacteria are likely to be poor antagonists. However, in practice the most attractive microbial antagonists for root diseases appear to be bacteria, particularly species of Pseudomonas and Bacillus. Advances in microbial genetics have provided methods whereby it may be possible in the near future to manipulate microorganisms and produce new antagonistic strains for particular purposes. However, the breeding of strains of this nature will require a much better understanding of interactions between microorganisms, plants and the soil than we have at present.  相似文献   
266.
267.
Coastal social ecological systems in eastern Africa are subject to a range of environmental, social and economic changes. They are already vulnerable to these multiple stressors, and the impacts of climate change are likely to further exacerbate their vulnerabilities. Some of these impacts may be observed and experienced already. The analysis presented in this paper is based on mixed methods empirical research exploring local perceptions of recent changes at four sites in coastal Tanzania and Mozambique. People recognise and rank a number of climate and non-climate stressors which have contributed towards more risky and less diverse livelihoods. Importantly, regional and international policy initiatives – in the form of river basin management in Mozambique and South Africa, and development of a Marine Protected Area in Tanzania – are perceived to further erode resilience and exacerbate vulnerabilities. We suggest this is a form of policy misfit, where policies developed to address a specific issue do not take account of cross-scale dynamics of change, the interactions between multiple stressors, nor longer term climate change. This policy misfit may be remedied by a move towards adaptive forms of governance, and necessitates an explicit focus on building the adaptive capacity of the poor and most vulnerable in society.  相似文献   
268.
Addressing uncertainties in the ERICA Integrated Approach   总被引:2,自引:2,他引:0  
Like any complex environmental problem, ecological risk assessment of the impacts of ionising radiation is confounded by uncertainty. At all stages, from problem formulation through to risk characterisation, the assessment is dependent on models, scenarios, assumptions and extrapolations. These include technical uncertainties related to the data used, conceptual uncertainties associated with models and scenarios, as well as social uncertainties such as economic impacts, the interpretation of legislation, and the acceptability of the assessment results to stakeholders. The ERICA Integrated Approach has been developed to allow an assessment of the risks of ionising radiation, and includes a number of methods that are intended to make the uncertainties and assumptions inherent in the assessment more transparent to users and stakeholders. Throughout its development, ERICA has recommended that assessors deal openly with the deeper dimensions of uncertainty and acknowledge that uncertainty is intrinsic to complex systems. Since the tool is based on a tiered approach, the approaches to dealing with uncertainty vary between the tiers, ranging from a simple, but highly conservative screening to a full probabilistic risk assessment including sensitivity analysis. This paper gives on overview of types of uncertainty that are manifest in ecological risk assessment and the ERICA Integrated Approach to dealing with some of these uncertainties.  相似文献   
269.
The Clean Development Mechanism (CDM) has successfully demonstrated that market-based mechanisms can achieve some cost effective emissions reductions in developing countries. However the distribution of CDM projects has been extremely uneven across countries and regions, and a few technologies and sectors have dominated the early stages of CDM experience. This has caused some to question whether the CDM has fallen short of its potential in contributing to sustainable development. We review the broad patterns of CDM project approvals and evaluate 10 CDM projects according to their sustainability benefits. The difficulty of defining “sustainable development” and the process of defining criteria by individual non-Annex 1 governments has meant that sustainable development concerns have been marginalized in some countries. Given these observed limitations, we present possible CDM policy futures, focusing on the main proposals for a post-2012 climate regime. Five options for enhancing the sustainable development benefits in the CDM are discussed, including proactive approaches to favour eligibility of emission reduction projects which ensure such co-benefits.  相似文献   
270.
Neonate larvae of codling moth, Cydia pomonella (L.), modify their behavior in the presence of saccharin, monosodium glutamate (MSG), or L(+)-2-amino-4-phosphonobutyric acid (L-AP4) by commencing their feeding earlier. Previously published pharmacological analysis demonstrated that phagostimulatory effects of MSG and L-AP4 (which elicit umami taste sensation in humans) are reversed by adenylate cyclase activator and phosphodiesterase inhibitor. In this study, by measuring the time needed to start ingestion of foliage treated with mixtures of phagostimulants and signal transduction modulators, we show that phagostimulatory effects of l-aspartate (the third hallmark umami substance) are also abolished by both adenylate cyclase activator and phosphodiesterase inhibitor, but not by phospholipase C inhibitor. However, stimulatory effects of hemicalcium saccharin were affected only by phospholipase C inhibitor. The results suggest that codling moth neonates use different transduction pathways for perception of hemicalcium saccharin and umami.  相似文献   
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