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   4849篇
  免费   149篇
  国内免费   110篇
安全科学   178篇
废物处理   42篇
环保管理   1298篇
综合类   1969篇
基础理论   357篇
环境理论   19篇
污染及防治   321篇
评价与监测   645篇
社会与环境   244篇
灾害及防治   35篇
  2023年   27篇
  2022年   38篇
  2021年   57篇
  2020年   165篇
  2019年   73篇
  2018年   65篇
  2017年   123篇
  2016年   157篇
  2015年   113篇
  2014年   182篇
  2013年   241篇
  2012年   174篇
  2011年   326篇
  2010年   167篇
  2009年   297篇
  2008年   234篇
  2007年   246篇
  2006年   234篇
  2005年   128篇
  2004年   151篇
  2003年   207篇
  2002年   192篇
  2001年   182篇
  2000年   212篇
  1999年   187篇
  1998年   161篇
  1997年   155篇
  1996年   96篇
  1995年   66篇
  1994年   86篇
  1993年   85篇
  1992年   51篇
  1991年   34篇
  1990年   20篇
  1989年   20篇
  1988年   15篇
  1987年   14篇
  1986年   17篇
  1985年   16篇
  1984年   18篇
  1983年   8篇
  1982年   10篇
  1981年   10篇
  1980年   9篇
  1979年   4篇
  1978年   13篇
  1977年   8篇
  1976年   4篇
  1972年   2篇
  1971年   5篇
排序方式: 共有5108条查询结果,搜索用时 15 毫秒
921.
The Lagoon Olho d'Água in Pernambuco State, Northeast Brazil has received increasing environmental concern due to significant stress from pollution in the catchment. The existing environmental problems are the result of great pressure from a broad range of human activities, especially in the last 10 years. Serious pollution exists mainly from some industrial and urban activities, which increased intensively after the eighties. There is a strong social and economical pressure for housing and construction near the lagoon, due to the available land nearby beaches and estuarine zone, and recently by growing tourism activities. Uncontrolled land use by low-income communities and the pressure for construction by developers have led to landfilling and to deterioration of water quality in the lagoon catchment. Improvement of the environmental conditions in the catchment needs integrated measures. Guidelines and some specific actions involving several institutions have been established and refer to sanitation and urban infrastructure as the main priorities. A main target is the construction of low-cost sewage system with smaller and decentralised treatment plants.  相似文献   
922.
浅谈县级市环境监测与环境管理的关系   总被引:1,自引:1,他引:0  
李伟 《四川环境》2001,20(3):76-78
监测与管理是环保工作中最基本、最重要的两个方面,本文较详细地探讨了县级市环境监测和环境管理的定义、范围及内容,并从依靠与服务的根本关系上强调;只有两者有机结合、互相支持才能搞好新形势下的环保工作。  相似文献   
923.
India is fast finding its place in the industrialized world and that is beginning to raise its environmental consciousness. The Delphi technique was used to prioritize specific needs and articulate a sustainable urban improvement strategy for the city of Mumbai (formerly Bombay). The Delphi technique is a means of achieving consensual validity among raters by providing them feedback regarding other raters' responses. Mumbai has several indigenous environmental groups that were tapped for activists and leaders; the study was conducted using ten environmentalists. In the initial phases the responses resulted in a range of possible program alternatives. The last two stages helped to seek out information that generated a consensus on the part of the respondent group. Statistical analysis methods included a hierarchical cluster analysis, mean, median, mode, and percent of agreement calculations using SPSS software. The face-to-face discussion in phase 4 clarified some issues and helped the group as a whole to outline the strategy for putting in place the essential elements of a framework to improve the quality of life in an urban environment.  相似文献   
924.
根据对各级环保机械综合信息技术应用的调研,提出环境监测综合信息系统设计原则及技术路线。  相似文献   
925.
本文论述了加强环境经济能力建设的背景、避免市场失灵及政府失灵的措施以及商业银行参与环保产业融资的经验.  相似文献   
926.
927.
ABSTRACT: In early 1997, the Texas Edwards Aquifer Authority implemented a pilot Irrigation Suspension Program with the objectives of increasing springflow and providing relief to municipalities during drought. Irrigators were paid an average of $234 per acre to suspend water use, a price higher than regional land rental rates. Auction theory and program implementation details suggest that the program implementation partially caused inflated bids. The Irrigation Suspension Program is also compared to two alternative programs: (1) subsidizing more efficient irrigation technology and (2) buying land. The irrigation suspension is found to be more cost‐effective relative to subsidizing improved irrigation efficiency because it can be put in place only when aquifer levels are low. Land purchase is a cheaper alternative if the bid levels remain at the levels observed.  相似文献   
928.
ABSTRACT: The probable maximum flood (PMF) currently serves as the design standard for many U.S. dams. Floods used for design have increased and currently thousands of dams in the U.S. would be overtopped and possibly fail using the latest calculated PMF at each dam site. Some researchers have suggested that modifying dams to accommodate the PMF could be wasteful. Objections to using the PMF for dam modification include: (1) larger spillway capacity may increase annual downstream flood losses, (2) benefit‐cost ratios may be low, (3) construction accidents associated with dam modification may cause fatalities, and (4) the dollar amount spent to save lives by making dams safer is often very high. Based on these objections, a procedure is presented for evaluating the effectiveness of a proposed dam modification. A change in spillway design policy is recommended. Accepting the status quo at a dam that cannot accommodate the PMF may be the best course of action.  相似文献   
929.
ABSTRACT: This study examines water consumption characteristics in Casablanca and analyzes approaches for sustainable water demand management. Research procedures involve the development and estimation of water demand models for the residential/commercial, industrial, and institutional sectors; forecasts of water demand to 2010; and simulation of the effects of a complex of water conservation methods on the forecasted demands. The results indicate that residential/commercial water demand is weakly responsive to price changes (elasticity =?0.448) while institutional water demand is slightly more responsive (elasticity =?0.648). The conservation approaches used in the simulations included public education, plumbing code revisions to require use of water conservation devices, leak detection and repair, pricing policy, metering, and pressure reduction. The results indicate that considerable saving in water use can be attained through a comprehensive water demand management program.  相似文献   
930.
随着可持续发展经济战略目标的实施,环境问题受到越来越多的重视,会讨如何在环境管理中发挥其作用,向有关的信息使用者提供有用的信息,这便是环境会计所研究的内容。  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