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   183篇
  免费   13篇
  国内免费   76篇
安全科学   4篇
环保管理   22篇
综合类   111篇
基础理论   94篇
污染及防治   12篇
评价与监测   2篇
社会与环境   13篇
灾害及防治   14篇
  2023年   1篇
  2018年   2篇
  2016年   2篇
  2015年   2篇
  2014年   1篇
  2011年   26篇
  2010年   9篇
  2009年   6篇
  2008年   7篇
  2007年   13篇
  2006年   5篇
  2005年   3篇
  2004年   50篇
  2003年   28篇
  2002年   9篇
  2001年   5篇
  2000年   2篇
  1999年   8篇
  1998年   9篇
  1997年   21篇
  1996年   5篇
  1995年   1篇
  1994年   4篇
  1993年   15篇
  1992年   10篇
  1991年   20篇
  1989年   8篇
排序方式: 共有272条查询结果,搜索用时 15 毫秒
231.
This paper deals briefly with the pollution caused by hazardous wastes in China, the hazardous waste management at present and the strategy that should be taken for hazardous waste management in the future. Hazardous waste problem has become one of the important environmental concerns in China. Hazardous waste have resulted in ecological and environmental destruction, caused damage to human health, and restricted economic development. Although a great effort has been devoted to the management of hazardous wastes, there remain many issues in legislation, experience, technology and finance to be solved. Some recommendations are made on the strategic measures for improving the hazardous waste management in China, particularly relating to legislation, technical development and international cooperation.  相似文献   
232.
The relation between EH [Se(VI)/Se(IV)] and pH of soil aqueous extract in Kaschin-Beck disease region and the effects of natural redox agents, namely humic substances, MnO2 and Fe2+, on the redox property of the system were studied. The results indicated that both humic acid and Fe2+ could enhance the reducibility of Se(VI) and MnO2, a limited oxidizability for Se(IV). Fe2+ showed a weak reducibility only at low pH value. The reducibilities of three sulfur-containing compounds for Se(VI) were in following order:thioglycollic acid > L-cysteine > sulfide  相似文献   
233.
The role of atmospheric aerosol composition in climate change   总被引:1,自引:0,他引:1  
The chemical composition of atmospheric aerosols has been investigated. Contributions ofsulfate and soot in aerosols to the atmospheric extinction are studied. Discussions are made on the problems of aerosol emitted from volcano, forest fires in northern China, 1987 and oil field fires in Kuwait, 1991. It is indicated that the changes in concentration, particle size, and chemical composition of aerosol after those events could have impacts on the climate change either regionally or globally and that the impact of aerosol particles on climate change could compensate for some temperature increase caused by greenhouse gases and the increase of surface intensity of ultraviolet radiation due to ozone layer depletion.  相似文献   
234.
EfectsofmainrangeandstrengthfactorsonchangeofCODinashalowlakeFanChengxinNanjingInstituteofGeographyandLimnology,ChineseAcad...  相似文献   
235.
吉林西部碱尘的通量与物质特征分析   总被引:1,自引:0,他引:1  
陈兵  胡克  介冬梅 《生态环境》2004,13(2):191-193
选择吉林西部两个典型地区,抽样采集碱尘样品,根据实测结果对日常形成的碱尘进行了通量测定;依据两个采样点的自然地理状况和实测采样记录,提出了吉林西部碱尘具有两种源区类型的认识,即以大布苏湖为代表的萎缩湖泡型和以姜家甸草场为代表的草场退化型。同时,通过对比分析不同时间和采样点的碱尘通量及源区特征,提出了吉林西部碱尘通量与风力条件、日照条件、pH值、物理性粘粒比例正相关,与植被覆盖度、地表物质粒级负相关。对碱尘元素分析结果表明,Ca、Na元素含量明显偏高,Fe、Al元素含量变化则较大;碱尘组成元素含量由多到少的顺序为:Ca、Na、Fe、Al、K、Mg、Ti,与普通尘暴元素组成有着明显的差别。  相似文献   
236.
随着肥料质量检测工作的深入开展,比色方法在许多检测项目中得到了越来越多的应用。作者在多年从事土壤肥料检测工作的基础上,介绍复混肥料化验检测中各种比色方法所使用仪器的特点,阐述了比色方法中标准曲线的配制和制作,分析比色方法中环境因素对检测结果的影响,为复混肥料的科学分析检测提供技术依据。  相似文献   
237.
青海湖流域主要生态环境问题及防治对策   总被引:6,自引:1,他引:6  
冯宗炜  冯兆忠 《生态环境》2004,13(4):467-469
分析了青海湖流域主要生态环境问题:湖水水面下降,水质恶化;草地退化日趋严重,“草原三害”面积不断增大。土地沙漠化面积不断扩大,水土流失严重;珍稀濒危野生动物濒临灭绝;渔业资源濒临枯竭。在此基础上,提出了五项防治对策:(1)提高广大干部群众的生态意识;(2)将“社会-经济-自然复合生态系统”概念引入到流域的治理中;(3)加强国家级自然保护区的建设;(4)大力发展林一草间作,增加植被覆盖度;(5)尽快组建“青海湖流域生态环境监测管理中心”。  相似文献   
238.
黑河流域土地利用变化对生态系统服务价值的影响   总被引:21,自引:4,他引:21  
王新华  张志强 《生态环境》2004,13(4):608-611
利用1987年和2000年1:100000Landsat TM图像解译数据分析了黑河流域土地利用变化,在此基础上,采用中国陆地生态系统服务价值的测算方法,评估了黑河流域土地利用变化引起的生态环境质量变化。结果表明,在过去的13年间,黑河流域土地利用变化总的趋势是森林、草地、河流冰川面积大幅减少,耕地、盐碱地和建筑用地迅速增加。这一变化损害了该区域的生态系统服务功能,使生态系统服务总价值(人民币)从404.22亿元/a下降到370.3亿元/a,损失率达到了8.39%。  相似文献   
239.
Abstract:  There is widespread agreement that biodiversity loss must be reduced, yet to alleviate threats to plant and animal species, the forces driving these losses need to be better understood. We searched for explanatory variables for threatened-species data at the country level through land-use information instead of previously used socioeconomic and demographic variables. To explain the number of threatened species in one country, we used information on land-use patterns in all neighboring countries and on the extent of the country's sea border. We carried out multiple regressions of the numbers of threatened species as a function of land-use patterns, and we tested various specifications of this function, including spatial autocorrelation. Most cross-border land-use patterns had a significant influence on the number of threatened species, and land-use patterns explained the number of threatened species better than less proximate socioeconomic variables. More specifically, our overall results showed a highly adverse influence of plantations and permanent cropland, a weaker negative influence of permanent pasture, and, for the most part, a beneficial influence of nonarable lands and natural forest. Surprisingly, built-up land also showed a conserving influence on threatened species. The adverse influences extended to distances between about 250 km (plants) and 2000 km (birds and mammals) away from where the species threat was recorded, depending on the species. Our results highlight that legislation affecting biodiversity should look beyond national boundaries.  相似文献   
240.
罗时 《劳动保护》2009,(3):50-51
2月9日晚,正当全国人民欢度元宵佳节之际,中央电视台新大楼北京配楼却成了一片火海。根据2月10日的通报,“央视大火”已造成7人受伤,1名消防员牺牲。而火灾原因“系业主单位不听治安民警劝阻,执意违法燃放烟花造成的”。  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