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   895篇
  免费   14篇
  国内免费   20篇
安全科学   71篇
废物处理   26篇
环保管理   193篇
综合类   191篇
基础理论   216篇
环境理论   3篇
污染及防治   139篇
评价与监测   55篇
社会与环境   25篇
灾害及防治   10篇
  2023年   9篇
  2022年   7篇
  2021年   11篇
  2020年   10篇
  2019年   18篇
  2018年   15篇
  2017年   40篇
  2016年   33篇
  2015年   27篇
  2014年   27篇
  2013年   50篇
  2012年   29篇
  2011年   43篇
  2010年   31篇
  2009年   38篇
  2008年   61篇
  2007年   47篇
  2006年   50篇
  2005年   37篇
  2004年   27篇
  2003年   31篇
  2002年   32篇
  2001年   16篇
  2000年   17篇
  1999年   12篇
  1998年   14篇
  1997年   16篇
  1996年   10篇
  1995年   16篇
  1994年   8篇
  1993年   15篇
  1992年   8篇
  1991年   8篇
  1990年   3篇
  1989年   8篇
  1988年   10篇
  1987年   10篇
  1986年   3篇
  1985年   9篇
  1984年   7篇
  1983年   4篇
  1982年   7篇
  1981年   8篇
  1980年   4篇
  1979年   6篇
  1978年   3篇
  1963年   4篇
  1954年   4篇
  1939年   2篇
  1938年   2篇
排序方式: 共有929条查询结果,搜索用时 21 毫秒
1.
2.
3.
Surveys of water recreational activities were conducted in the Peel-Harvey estuary. Channels used by recreationists to gain information about water quality, the perception of water quality and resulting behaviour were investigated. This study showed that personal perception, local knowledge and history, absence of warnings and residency were major factors contributing to risk perception and behaviour in this recreational community. Management strategies should take this information into account to achieve maximal outcomes.  相似文献   
4.
In a Scots pine forest the throughfall deposition and the chemical composition of the soil solution was monitored since 1984. (Inter)national legislation measures led to a reduction of the deposition of nitrogen and sulphur. The deposition of sulphur has decreased by approximately 65%. The total mineral-nitrogen deposition has decreased by ca. 25%, which is mainly due to a reduction in ammonium-N deposition (−40%), since nitrate-N deposition has increased (+50%). The nitrogen concentration in the upper mineral soil solution at 10 cm depth has decreased, leading to an improved nutritional balance, which may result in improved tree vitality. In the drainage water at 90 cm depth the fluxes of NO3 and SO42− have decreased, resulting in a reduced leeching of accompanying base cations, thus preserving nutrients in the ecosystem. It may take still several years, however, before this will meet the prerequisite of a sustainable ecosystem.  相似文献   
5.
This paper demonstrates the potential for induced preference experiments to test previously unverified explanations of observed behavior in contingent valuation surveys. The NOAA Panel on Contingent Valuation called for experimental evidence on potential biases in the double referendum format. We test Carson, Groves, and Machina's (Incentives and informational properties of preference questions, Plenary address to the European Association of Resource and Environmental Economists, Oslo, Norway, June 1999) simple cost uncertainty and weighted averaging explanations of inconsistent responses to follow-up offers in such double referenda against a baseline of certainty and truthful preference revelation. The results find evidence to support the Weighted Average hypothesis. Results regarding the cost uncertainty hypothesis are more ambiguous and merit further investigation.  相似文献   
6.
The Countryside and Rights of Way Act 2000 places a duty on highways and national park authorities to establish local access forums (LAFs), to advise on the improvement of public access to land for the purposes of open air recreation and enjoyment. This paper examines these proposals in the context of recent academic and political debates about deliberative democracy, and empirical research on the nature and practice of existing access liaison groups and forums. While demonstrating that the proposed LAFs are consistent with contemporary constructs of participative, if not deliberative democracy, the paper argues that most existing groups and forums fall short of this ideal, in a number of significant respects. The paper proceeds to discuss the extent to which the draft regulations for LAFs in England and Wales address these issues, and concludes by questioning the extent to which such consultative arrangements can contribute to new forms of local governance.  相似文献   
7.
8.
9.
Mercury is released to the environment from various anthropogenic and natural sources. This work is a compilation of mercury emissions from anthropogenic sources in Ontario, Canada. The goal of our study was to identify all sources of mercury, and develop an emission inventory of anthropogenic mercury in Ontario. The result of our investigation revealed that combustion of fossil fuels and emissions from landfill sites are two primary sources of mercury to the atmosphere. Other sources of significance are emissions from waste incinerators, various industrial activities, and cement production. Total mercury emission in Ontario is estimated as 4100 kg per year.  相似文献   
10.
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