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   1713篇
  免费   67篇
  国内免费   171篇
安全科学   126篇
废物处理   84篇
环保管理   962篇
综合类   407篇
基础理论   199篇
污染及防治   57篇
评价与监测   66篇
社会与环境   14篇
灾害及防治   36篇
  2023年   13篇
  2022年   15篇
  2021年   19篇
  2020年   22篇
  2019年   80篇
  2018年   9篇
  2017年   13篇
  2016年   19篇
  2015年   16篇
  2014年   34篇
  2013年   48篇
  2012年   47篇
  2011年   49篇
  2010年   46篇
  2009年   24篇
  2008年   69篇
  2007年   19篇
  2006年   29篇
  2005年   18篇
  2004年   39篇
  2003年   71篇
  2002年   160篇
  2001年   140篇
  2000年   172篇
  1999年   135篇
  1998年   104篇
  1997年   80篇
  1996年   214篇
  1995年   58篇
  1994年   17篇
  1993年   14篇
  1992年   5篇
  1991年   5篇
  1990年   2篇
  1989年   9篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   22篇
  1984年   38篇
  1983年   35篇
  1982年   4篇
  1981年   2篇
  1980年   7篇
  1978年   5篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
  1971年   14篇
  1967年   1篇
排序方式: 共有1951条查询结果,搜索用时 781 毫秒
581.
The Association of Southeast Asian Nations has agreed that environmental protection and sustainable use of natural resources are essential for sound economic development. The Environmental Impact Assessment is viewed as an important management tool and an ASEAN Experts Group on the Environment has been working for several years on a model especially adapted to the region and also on case studies of the implementation of EIA. Progress so far has been frustratingly slow due to misunderstanding, a lack of ecological data, inadequate trained manpower and institutional shortcomings for compliance. The author advocates collaboration on an ASEAN model for performing EIA as a means of accelerating acceptance and implementation. The concept of Adaptive Environmental Assessment and Management is proposed as a prototype.  相似文献   
582.
583.
This report describes the work of an international group that is supported in part by the Dutch Ministry for Environment and is chaired by Frans Evers, the Ministry's Deputy Director-General for Environmental Protection.  相似文献   
584.
试图提出了一种以环境损失作为评价污染源布局判据的观点,给出了大气环境损失系数的计算方法及污染源合理布局优化计算模型,并结合实例作了进一步的分析。  相似文献   
585.
我国物理监测工作的现状与建议   总被引:1,自引:1,他引:1  
描述了我国物理监测(包括噪声监测、振动监测、辐射监测等)工作现状,介绍了环境监测系统物理监测的人员、仪器、能力以及相关标准、规范等情况,分析了物理监测工作存在的不足并对今后更好地开展物理监测工作提出了建议。  相似文献   
586.
颗粒态重金属通过河流与大气向海洋输送   总被引:8,自引:2,他引:8  
本文综述了河流与大气向海洋输送颗态重金属的过程、特点及输送通量、参考文献83篇。  相似文献   
587.
对加强危险废物(有害废物)和有毒化学品管理的思考   总被引:2,自引:0,他引:2  
论述了危险废物的危害性,对危险废物及管理方面优无考虑的问题,结合国内外,尤其是辽宁省的具体运行进展情况提出相关对策与建议。  相似文献   
588.
The US Department of Defense (DOD) manages over 10.1 million ha of land, much of which is used for training military personnel. However, vast sections receive little or no use, and military lands have become refuges for many species. At Fort McCoy, Wisconsin, USA, populations of the endangered Karner blue butterfly (Lycaeides melissa samuelis) are found in oak and pine barren communities where wild lupine (Lupinus perennis), a perennial forb required by Karner blue butterfly larvae, still occurs. Oak and pine barren communities are disturbance-dependent, and the barrens ecosystems in the Midwest have declined in extent by 98% because of fire suppression, succession, and habitat fragmentation. We studied the effects of disturbance by military manuever training on the density of lupine and Karner blue butterfly at Fort McCoy. We also wanted to determine whether military training activity could enhance Karner blue butterfly habitat. At locations where tracked vehicles had driven through lupine patches, the abundance of lupine and nectar-producing plants was greater in the median strip between vehicle ruts than in vehicle ruts or 5 m outside the vehicle ruts. The proportion of lupine stems with Karner blue butterfly larvae feeding sign (the ratio of stems fed upon to stems examined) was greater in areas where military vehicles had traveled than where they had not. The proportion of lupine stems with feeding sign and lupine stem density was also positively related to the occurrence of prior bivouacs and fires caused by military munitions. Shrub and forest canopy abundance were lower in areas traveled by tracked vehicles. At the scale of the lupine patch, lupine abundance and the proportion of lupine stems with feeding sign were positively correlated with military training activities, suggesting that maintenance of lupine habitat can be achieved in concert with military training.  相似文献   
589.
Using Basin Area Stream Survey (BASS) data from the United States Forest Service, we evaluated how timber harvesting influenced patterns of variation in physical stream features and regional fish and macroinvertebrate assemblages. Data were collected for three years (1990–1992) from six hydrologically variable streams in the Ouachita Mountains, Arkansas, USA that were paired by management regime within three drainage basins. Specifically, we used multivariate techniques to partition variability in assemblage structure (taxonomic and trophic) that could be explained by timber harvesting, drainage basin differences, year-to-year variability, and their shared variance components. Most of the variation in fish assemblages was explained by drainage basin differences, and both basin and year-of-sampling influenced macroinvertebrate assemblages. All three factors modeled, including interactions between drainage basins and timber harvesting, influenced variability in physical stream features. Interactions between timber harvesting and drainage basins indicated that differences in physical stream features were important in determining the effects of logging within a basin. The lack of a logging effect on the biota contradicts predictions for these small, hydrologically variable streams. We believe this pattern is related to the large scale of this study and the high levels of natural variability in the streams. Alternatively, there may be time-specific effects we were unable to detect with our sampling design and analyses.  相似文献   
590.
The complexity of fluvial systems necessitates interdisciplinary research in fluvial geomorphology and aquatic ecology to develop a fundamental understanding of interconnections among biotic and abiotic aspects of these systems. Integrated knowledge of this type is vital for environmental management of streams in human-dominated environments. A conceptual framework is presented for integrating geomorphological and ecological research on streams in East Central Illinois, USA, a glaciated low-relief agricultural landscape. The framework embodies a multiscale perspective in which a geomorphological conception of the fluvial system is used to define a hierarchy of characteristic spatial scales for exploring important linkages between stream geomorphology and aquatic ecology. The focus ecologically is on fish, because a rich body of historical information exists on fisheries in East Central Illinois and because past work has suggested that availability of physical habitat is a major factor influencing the community characteristics of fish in this human-altered environment. The hierarchy embodied in the framework includes the network, link, planform, bar unit, bar element, and bedform/grain scales. Background knowledge from past research is drawn upon to identify potential linkages between geomorphological and ecological conditions at each of these scales. The conceptual framework is useful for guiding integrated ecogeomorphological research at specific scales and across different scales. It also is helpful for illustrating how widespread human modification of streams has catastrophically altered the scalar structure of fluvial systems in East Central Illinois. Knowledge emerging from the integrated research provides a basis for environmental-management schemes directed toward stream naturalization.  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