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   43281篇
  免费   773篇
  国内免费   4704篇
安全科学   1646篇
废物处理   2040篇
环保管理   4990篇
综合类   12376篇
基础理论   9809篇
环境理论   16篇
污染及防治   12461篇
评价与监测   2533篇
社会与环境   2143篇
灾害及防治   744篇
  2023年   325篇
  2022年   820篇
  2021年   747篇
  2020年   520篇
  2019年   588篇
  2018年   888篇
  2017年   973篇
  2016年   1189篇
  2015年   1169篇
  2014年   1687篇
  2013年   3793篇
  2012年   1908篇
  2011年   2380篇
  2010年   1881篇
  2009年   1938篇
  2008年   2112篇
  2007年   2021篇
  2006年   1846篇
  2005年   1439篇
  2004年   1330篇
  2003年   1424篇
  2002年   1299篇
  2001年   1539篇
  2000年   1200篇
  1999年   957篇
  1998年   726篇
  1997年   684篇
  1996年   731篇
  1995年   677篇
  1994年   588篇
  1993年   534篇
  1992年   501篇
  1991年   457篇
  1990年   448篇
  1989年   423篇
  1988年   382篇
  1987年   308篇
  1986年   278篇
  1985年   298篇
  1984年   308篇
  1983年   302篇
  1982年   343篇
  1981年   279篇
  1980年   251篇
  1979年   274篇
  1978年   246篇
  1977年   214篇
  1976年   213篇
  1974年   212篇
  1973年   191篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
81.
82.
83.
84.
85.
86.
Community evacuation following a chlorine release, Mississippi   总被引:1,自引:0,他引:1  
On 7th September 1986, four miles north of Collins, Mississippi, a train transporting chlorine derailed. Two cars ruptured and gas escaped. As a result, 100 families were evacuated. To study the evacuation process, we conducted person-to-person interviews with sixty-two families staying in the evacuation center. Only 52.5% of the families received their first directive to evacuate directly from police or other officials. Delays in evacuating tended to be shorter when people were warned by the police and were told the reason for evacuating. Lack of personal transportation and preexisting health problems resulted in delays in evacuation. Concerns about evacuation included fear of looting, lack of a place to go, lack of transportation, difficulty in moving with children and elderly persons, and the need to take care of pets. One third of the interviewees reported feeling panic. Community evacuation procedures would be improved if: (1) officials contact all households directly; (2) the warning message addresses people's concerns; and (3) transportation is provided.  相似文献   
87.
ABSTRACT: This paper describes the formulation of an Index of Water Quality to evaluate the level of pollution in fresh water. A Four-Round Delphi equation, using a panel of seven nationally recognized water scientists, was performed to ascertain the pollutants to be included in the index, the relationship between the quantity of these pollutants in the water and the resulting quality of the water, and the importance of each pollution variable to each water use as well as to overall pollution. A multiplicative index was used to bring the pollutants together into one system.  相似文献   
88.
89.
Material suppliers and industrial metabolism   总被引:1,自引:1,他引:0  
Life Cycle Assessment (LCA) is not sufficiently tailored to the analysis of strategic environmental problems of material suppliers. Sustainable development calls for a reduction by a factor of 10 to 20 in the material intensity of the economy, a situation which leads to dramatic shifts in markets for raw materials. Furthermore, a material supplier might have major improvement options in the material’s numerous downstream uses. LCAs, however, can’t cover these two aspects. An adapted form of Substance Flow Analysis (SFA) may be an answer. This approach defines a system in relation to the flow of a specific material through society. All environmental interventions related to the material are inventoried. An emission evaluation indicates the dominant environmental bottlenecks, given the current market volume of each application of the material. This helps to identify improvement options and strategic choices in market portfolios. Scenario analysis on potential measures can further indicate changes of material flows — and thus markets — in the system. The approach is illustrated with a case study on chlorine.  相似文献   
90.
The situation and the latest findings of forest damage research in Germany are discussed. A newly developed concept for this research is described. This concept allows to identify the drawbacks of the recent damage research concept but also the integration of results compiled up to now. The importance for including natural occurring stress factors such as climate, soil conditions or local situation of individual species is outlined.  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