首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1360篇
  免费   24篇
  国内免费   3篇
安全科学   47篇
废物处理   53篇
环保管理   279篇
综合类   124篇
基础理论   392篇
环境理论   1篇
污染及防治   327篇
评价与监测   83篇
社会与环境   70篇
灾害及防治   11篇
  2022年   8篇
  2021年   10篇
  2020年   16篇
  2019年   12篇
  2018年   25篇
  2017年   12篇
  2016年   44篇
  2015年   30篇
  2014年   34篇
  2013年   125篇
  2012年   35篇
  2011年   67篇
  2010年   48篇
  2009年   60篇
  2008年   56篇
  2007年   71篇
  2006年   57篇
  2005年   52篇
  2004年   40篇
  2003年   44篇
  2002年   45篇
  2001年   39篇
  2000年   27篇
  1999年   26篇
  1998年   18篇
  1997年   20篇
  1996年   20篇
  1995年   34篇
  1994年   19篇
  1993年   20篇
  1992年   13篇
  1991年   25篇
  1990年   19篇
  1989年   15篇
  1988年   9篇
  1987年   16篇
  1986年   15篇
  1985年   11篇
  1984年   25篇
  1983年   10篇
  1982年   14篇
  1981年   9篇
  1980年   9篇
  1979年   9篇
  1978年   6篇
  1977年   12篇
  1975年   9篇
  1974年   8篇
  1973年   5篇
  1971年   7篇
排序方式: 共有1387条查询结果,搜索用时 312 毫秒
351.
A fuzzy decision analysis method for integrating ecological indicators was developed. This was a combination of a fuzzy ranking method and the analytic hierarchy process (AHP). The method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, we were able to point out areas that were in relatively poor condition and/or vulnerable to future deterioration. The method offered an easy and comprehensive way to combine the strengths of fuzzy set theory and the AHP for ecological assessment. Furthermore, the suggested method can serve as a building block for the evaluation of environmental policies.  相似文献   
352.
This article illustrates the way environmental insurance policies can be used, and discusses some of the major considerations that must or should be taken into account when making a decision both as to coverage and as to the structure of a transaction. Diane Smith has been practicing environmental law for over 25 years. In this article, she discusses using the new environmental insurance policies to facilitate deals. The issues raised have come up in one or more recent transactions that have utilized the new policy forms to make otherwise difficult or impossible transactions work. © 2001 John Wiley & Sons  相似文献   
353.
354.
Systematic conservation planning is intended to inform spatially explicit decision making. Doing so requires that it be integrated into complex regulatory and governance processes, and there are limited instances where this has been achieved effectively. South Africa is a global leader in the application of conservation plans, the outputs of which are widely used for spatial planning and decision making in many spheres of government. We aimed to determine how conservation planning in the country progressed from theory to implementation, and to identify practical actions that enabled this transition, by assessing temporal trends in the characteristics of conservation plans (1990–2017, n = 94). Since 2010 conservation planning has entered an operational period characterized by government leadership of plans, administrative rather than ecological planning domains, decreasing size of planning units, increasing emphasis on end-user products, and scheduled revision of plans. Key actions that enabled this progression include transitioning leadership of plans from scientists to practitioners, building capacity within implementing agencies, creating opportunities to integrate plans in legislative processes, establishing a strong community of practice, adopting implementation-focused methods, and balancing standardization with innovation. Learning from this model will allow other countries, particularly those with a similar megadiverse, developing context, to operationalize conservation planning into spatial planning and decision making.  相似文献   
355.
A field test was conducted to determine if ozone pollution adversely affected the chlorophyll content and seed yield of soybean. Eight soybean cultivars were grown to maturity in test plots in central New Jersey; one-half of the plots was treated with an antioxidant (ethylenediurea) to protect the plants from the effects of ambient ozone and one-half was left untreated. Periodic chlorophyll measurements revealed no significant difference between EDU-treated and untreated plots during the major part of plant growth. The absence of a yield effect predicated on the normal chlorophyll content was corroborated by actual total seed measurement. Our results did not support predictive models that forecast a significant yield reduction from a 7-h seasonal mean of 0.058 ppm 03, but agreed with results obtained previously in Maryland and Georgia.  相似文献   
356.
This paper considers whether the Journal of Environmental Economics and Management (JEEM) has had impact on the development and applications of the methods used to estimate economic values for non-marketed environmental resources. Journal editors control the research dialogue in a discipline and as a result have the potential to influence its scope and direction. At least four areas of research have been influenced by JEEM, the theory and practice of contingent valuation, the use of preference restrictions in valuation, the development and application of corner solution models, and the role of substitution between environmental resources for valuation.  相似文献   
357.
/ We identified and ranked 108 resident and migratory wildlife taxa on John F. Kennedy Space Center (KSC) that were vulnerable to local, regional, or global extinction. We ranked taxa based on their vulnerability to extinction, their potential role for maintaining faunal integrity, and the relevance of KSC for maintaining their populations in the United States and Florida. Several taxa, not listed by agencies, were vulnerable to regional or global extinction. Many taxa not vulnerable to global extinction were vulnerable to local and regional extinction. Top predators were vulnerable to extinction because of small population size, isolation from other populations, and road mortality. Many taxa were dependent on habitat conditions at different geographic locations so that conservation required greater collaboration among land owners, managers, and researchers at local, regional, and global scales.KEY WORDS: Biological diversity; Endangered species; Conservation  相似文献   
358.
The implications of the treatment of uncertainty in the definition of optimal investment criteria for irreversible allocations of unique environmental resources are considered herein. This analysis argues that the single-project, orientation of conventional cost-benefit analysis can lead to inconsistent decisions because it fails to take account of the potential for risk pooling across projects. In the models discussed in this paper uncertainty arises because the planner must estimate the net benefits associated with a mix of developed and preserved natural environments. The results suggest that the criteria for optimal investment plans will be affected by those factors influencing this uncertainty. Both the scale and timing of optimal investments may be altered from those prescribed with the conventional (Fisher-Krutilla-Cicchetti rule) framework when the potential for risk pooling is introduced. Thus, it is important to consider as a part of the specification of the objective function the factors which give rise to uncertainty.  相似文献   
359.
Collectively, surface coating operations using paints with hydrocarbon solvents may well be the largest industrial source of volatile organic compounds (VOC) and hazardous air pollutants (HAP). Most surface coating operations involve the manual application of paint with spray equipment inside a paint spray booth. The booth exhaust system collects the solvent fumes and then exhausts them through a stack to the atmosphere. Stack emissions are characteristically high in flow rate and low in concentration. Since control equipment is sized based on exhaust flow rate rather than concentration, control of VOC and HAP requires large, expansive abatement equipment. Simple, effective designs employing recycling of air have greatly reduced the exhaust flow rate and the cost of the control equipment. However, these designs are not popular because they are burdened by various flaws, notably worker endangerment. The Mobile Zone recirculation system can be incorporated into new construction or retrofitted to existing spray booths and will reduce the exhaust volumes ranging from 65 to 95 percent without adversely affecting the production rate, production quality or worker safety.  相似文献   
360.
Electron backscatter diffraction (EBSD) is a powerful microscopic technique to characterise the crystallography of biomineralisation. Here, we use high-resolution EBSD to characterise one of the least studied shells in the ocean, the female argonaut brood chamber, and to examine the changes in shell microstructure in response to incubation in decreased pH conditions. The thin (225 μm) shell of Argonauta nodosa is magnesium calcite with an average magnesium content of ca. 5.1 Wt % MgCO3. EBSD and scanning electron microscopy (SEM) revealed that calcification of the shell is bidirectional with formation of irregular crystalline grains. Following a 2 week incubation in a range of pH treatments (pH, 8.1–7.2), shell fragment weight decreased by dissolution in pH ≤ 7.8. EBSD and SEM revealed altered shell crystallography and microstructure at pH ≤ 7.4 due to preferential etching down crystallite grain boundaries and a change in crystalline orientation on both the inner and outer shell surfaces. Our study highlights the value of EBSD for the detailed examination of biogenic carbonates and its potential use in the field of ocean acidification research.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号