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   45223篇
  免费   457篇
  国内免费   396篇
安全科学   1266篇
废物处理   1864篇
环保管理   5855篇
综合类   7271篇
基础理论   12331篇
环境理论   25篇
污染及防治   11744篇
评价与监测   3028篇
社会与环境   2389篇
灾害及防治   303篇
  2022年   350篇
  2021年   373篇
  2020年   266篇
  2019年   345篇
  2018年   658篇
  2017年   654篇
  2016年   961篇
  2015年   768篇
  2014年   1114篇
  2013年   3539篇
  2012年   1345篇
  2011年   1903篇
  2010年   1635篇
  2009年   1632篇
  2008年   1907篇
  2007年   2029篇
  2006年   1829篇
  2005年   1537篇
  2004年   1535篇
  2003年   1462篇
  2002年   1410篇
  2001年   1851篇
  2000年   1295篇
  1999年   812篇
  1998年   633篇
  1997年   609篇
  1996年   658篇
  1995年   669篇
  1994年   620篇
  1993年   572篇
  1992年   572篇
  1991年   521篇
  1990年   530篇
  1989年   555篇
  1988年   486篇
  1987年   405篇
  1986年   369篇
  1985年   407篇
  1984年   419篇
  1983年   438篇
  1982年   451篇
  1981年   370篇
  1980年   332篇
  1979年   393篇
  1978年   321篇
  1977年   275篇
  1976年   273篇
  1975年   253篇
  1974年   241篇
  1972年   250篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
This paper demonstrates empirically the gain from adopting more general equilibrium approaches in projecting the effects on domestic output and international trade of environmental controls. The suggested models include a partial equilibrium case where all industries are treated independently, an intermediate case incorporating effects in supplying industries, and general equilibrium formulations based on alternative macroeconomic conditions. U. S. data is used to evaluate these models. Under both pollutor pays and subsidy financing schemes, moving from the simplest case to the intermediate model results in quite different industry projections. Including macroeconomic factors appears particularly important in the classical setting.  相似文献   
993.
Involuntary eye movements in salamanders   总被引:1,自引:0,他引:1  
  相似文献   
994.
Sharlin SA  Mor-Barak M 《Disasters》1983,7(2):142-147
This paper describes the help given by the social services department of a shipping company to bereaved families following a shipping disaster. In the absence of clear, factual and prompt information from an authoritative source, there is a tendency for bereaved individuals to deny their loss and thereby delay the process of mourning and eventual recovery. Appropriate intervention and support can help to overcome this tendency as was seen in the Madasa case.  相似文献   
995.
Taylor AJ 《Disasters》1983,7(1):37-40
This paper defines the various levels within government, the voluntary agencies and the community which might benefit from training and makes suggestions as to where the emphasis should be placed. It points out that training programmes should be designed to meet the expressed needs of a particular group of trainees as well as be related to the current or potential disaster situation.  相似文献   
996.
997.
In the control of pollution, two apparently important facts are often negelected: (1) removal of a particular pollutant from a particular source and location may merely result in transforming it into a pollutant, or pollutants of different forms, in other locations; (2) the activity of pollution control itself requires inputs, the production of which may generate additional pollutants. In order to achieve positive environmental control, these two facts must be considered in selecting control processes and in determining optimum control standards. It is necessary that an integrated approach to pollution control be taken, making allowances for ecological inter-relations. As practiced today, pollution control is handled as separate problems of disposing gas, liquid and solid wastes. This paper proposes a model for evaluating the total environmental impact of a pollution control process or method. Theoretical criteria for determining an optimum control level with or without resource constraint are also derived.  相似文献   
998.
This paper shows that spent lubricating oils from automobile engines generate carboxylic acids on environmental exposure. Samples of exposed oils, isolated from polluted river water and shore muds obtained from various locations, showed a direct proportionality between carboxylic acid content and time of exposure. Carboxylic acids were isolated by solvent extraction and studied by infrared spectroscopy.  相似文献   
999.
1000.
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