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   11013篇
  免费   1141篇
  国内免费   2179篇
安全科学   2612篇
废物处理   144篇
环保管理   1656篇
综合类   5694篇
基础理论   1434篇
环境理论   14篇
污染及防治   507篇
评价与监测   739篇
社会与环境   593篇
灾害及防治   940篇
  2024年   47篇
  2023年   262篇
  2022年   410篇
  2021年   536篇
  2020年   507篇
  2019年   509篇
  2018年   425篇
  2017年   542篇
  2016年   616篇
  2015年   645篇
  2014年   653篇
  2013年   874篇
  2012年   901篇
  2011年   994篇
  2010年   653篇
  2009年   733篇
  2008年   538篇
  2007年   697篇
  2006年   683篇
  2005年   512篇
  2004年   362篇
  2003年   348篇
  2002年   295篇
  2001年   244篇
  2000年   237篇
  1999年   207篇
  1998年   145篇
  1997年   142篇
  1996年   90篇
  1995年   122篇
  1994年   66篇
  1993年   67篇
  1992年   44篇
  1991年   40篇
  1990年   19篇
  1989年   17篇
  1988年   16篇
  1987年   12篇
  1986年   15篇
  1985年   8篇
  1984年   13篇
  1983年   7篇
  1982年   11篇
  1981年   14篇
  1980年   9篇
  1978年   7篇
  1977年   7篇
  1974年   5篇
  1973年   7篇
  1971年   8篇
排序方式: 共有10000条查询结果,搜索用时 26 毫秒
971.
One major source of water-related health problems is the improper disposal of toxic substances in the environment. Toxic materials leaching from unregulated and unlined pits, ponds, lagoons, and landfills have created a widespread environmental nightmare in the United States and many other parts of the world. At present, there are two major and interrelated components of this problem in the United States. The first is the issue of cleaning up abandoned disposal sites that pose actual or potential threats to water supplies. The second aspect of the problem concerns the necessity of siting proper management, treatment, or disposal facilities in the future. Priorities must be set to allow efficient, effective, and equitable allocation of the scarce resources that are available for accomplishing these tasks.This article examines a number of the issues involved in setting these priorities, and presents the results obtained from a study of risk estimation and evaluation in the context of groundwater contamination by toxic substances. The article introduces a new concept of risk estimation, which is shown to produce more accurate and credible risk analyses. Finally, the relationships between risk credibility and public perceptions of procedural fairness and equity are examined as these factors bear on the institutional aspects of implementing policies for site cleanup and/or facility siting.  相似文献   
972.
The paper attempts to conceptualise a range of problems arising from project appraisals. The author presents some general considerations concerning the role of social appraisal in territorial planning, the theoretical weaknesses of cost‐benefit analysis in assessing the effects of projects on territorial resources and some questions relating to assessment methodologies and the welfare foundations of social appraisal within planning practices. The author moves away from evaluation as a technical process towards one which also incorporates ‘practical’ knowledge in a process of argumentation.  相似文献   
973.
ABSTRACT: Third World irrigation and drainage systems have experienced major declines recently in both capability and performance. This is due initially to working them well beyond their design capaci-capacities; scouring, sedimentation, and overtopping result. Chronic O&M underfunding then adds heavily to this worsening malaise. International donors have assisted irrigation departments with rehabilitation projects and programs to improve O&M effectiveness on a grand (billions of dollars) scale. Despite their historical propensity to examine, almost fastidiously, program economic justifications (B/C, IRR, etc), the donors apparently have glossed over two basic analytic elements for (a) more spending on O&M as distinct from an equivalent spending on other means to provide farmers with an m3 of water; and (b) different levels of O&M spending on canals and drains. Surely those different levels provide differing benefits, in total, and at the margin. Which level is most economic? This paper identifies these latter analytical issues, posits methodologies key to an O&M spending level analysis, and discusses the information base. Particular attention is paid to identifying relevant costs and benefits, and to suggesting supplementary criteria for O&M spending level selection. The paper is an exercise in delineation of an imminently practical area of irrigation engineering economics.  相似文献   
974.
ABSTRACT: The Nonlinear Risk-Benefit (NRB) Algorithm includes risk as one of the objectives in a multiple-objective optimization problem. The NRB Algorithm is derived by extending the Surrogate Worth Trade-Off method to quadratic programming. This category of problem is common in water resources planning and design, especially multipurpose reservoir systems. Consequently, an example is given using the algorithm for optimally operating a multipurpose reservoir.  相似文献   
975.
AHP法在废水治理工程评价中的应用   总被引:1,自引:0,他引:1  
翟由涛 《化工环保》1995,15(3):175-177
应用层次分析法(AHP)的原理,建立了废水处理工程的评价模型,并结合废水处理的实例进行了研究,结果证明了AHP法是评价废水处理工程的有效方法。  相似文献   
976.
回顾了国内外区域开发环境管理的发展历程,简要论述了区域环境规划与区域开发环境影响评价在区域开发环境管理中的作用和地位以及两者的相互关系。  相似文献   
977.
The thermal oxidative stability of various formulations based on emulsion-grade ABS was studied by the chemiluminescence technique. Emulsion products were found to be essentially less stable than ionic mass polymerization resins. Among the antioxidants studied, Santonox R is clearly more efficient than Irganox 1076 and Irganox 3114, and its superiority is reflected primarily in improved induction period values. The introduction of Tinuvin 770 and Tinuvin 328 UV stabilizers into emulsion resins does not change the durability of the products. In mixtures where both Irganox 1076 and UV stabilizers are present, a certain antagonistic effect was noted at high UV stabilizer concentrations.  相似文献   
978.
In reaction to a paper inEnvironmental Management in which the sense and sensibility of environmental assessments of packaging were questioned, it is argued that these types of assessments may be very useful, provided the relevant types of questions are posed. These boundary conditions are discussed, along with an overview of more recent methodological developments with respect to environmental assessment of products.  相似文献   
979.
Risk management practices under the current environmental regulations is a long, complex process that considers scientific, technologic, and management factors to develop various regulatory standards and pollution control measures. Using the mandatory enforcement approach, sometimes referred to as “command-and-control”, a set of preliminary environmental goals, such as better air and water qualities, were achieved. However, the information-intensive nature of the risk management process and the lack of flexibility in conventional regulatory methods to changing economic and technologic realities of the decade has created interest among risk managers to examine some innovative management approaches. Above all, environmental problems of a global scale require novel management methods while striving to achieve the desired environmental goals. As the principal analytical tool in risk management, quantitative risk assessment exerts considerable influence on the risk management process. Therefore, advances in risk management are closely associated with scientific developments that enhance the risk assessment process, particularly those efforts aimed at improving human exposure and toxicity assessments. Market incentives, information dissemination, creative enforcement practices, and interagency and intergovernmental interactions were identified as the key elements of innovative environmental risk management practices. This paper will present an overview of the emerging innovative risk management approaches.  相似文献   
980.
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