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   17143篇
  免费   1397篇
  国内免费   2544篇
安全科学   1912篇
废物处理   210篇
环保管理   3635篇
综合类   9181篇
基础理论   1796篇
环境理论   7篇
污染及防治   833篇
评价与监测   1999篇
社会与环境   1042篇
灾害及防治   469篇
  2024年   94篇
  2023年   316篇
  2022年   418篇
  2021年   516篇
  2020年   588篇
  2019年   452篇
  2018年   418篇
  2017年   618篇
  2016年   708篇
  2015年   772篇
  2014年   880篇
  2013年   1128篇
  2012年   1167篇
  2011年   1365篇
  2010年   931篇
  2009年   983篇
  2008年   798篇
  2007年   1154篇
  2006年   1085篇
  2005年   873篇
  2004年   746篇
  2003年   708篇
  2002年   671篇
  2001年   531篇
  2000年   542篇
  1999年   442篇
  1998年   300篇
  1997年   317篇
  1996年   236篇
  1995年   235篇
  1994年   159篇
  1993年   157篇
  1992年   102篇
  1991年   98篇
  1990年   56篇
  1989年   45篇
  1988年   51篇
  1987年   40篇
  1986年   34篇
  1985年   26篇
  1984年   30篇
  1983年   28篇
  1982年   35篇
  1981年   39篇
  1980年   34篇
  1979年   32篇
  1978年   21篇
  1977年   18篇
  1975年   15篇
  1973年   19篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
11.
阐述了开展工业区群环境影响评价的意义,比较了单个工业园区和工业区群环评的异同,以广州番禺区工业区群环评项目为例,简述了该环评的主要内容和特点,并提出了建议。  相似文献   
12.
13.
Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Córdoba city, Argentina. The study area receives regional pollutants and was categorized taking into account traffic level, industrial density, type of industry, location of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur, soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins, pigments, HPCD, and MDA as they are responsible for the major variability of data.  相似文献   
14.
Benthic macroinvertebrate communities in streams adjacent to cornfields, streams where cows had unrestricted access, and reference locations without agriculture were compared to examine the effects of local land use and land use/land cover in the watershed. At each local site, macroinvertebrates and a variety of habitat parameters were measured upstream, adjacent, downstream, and farther downstream of the local land use. A geographic information system (GIS) was used to calculate drainage basin area, land use/land cover percentages in each basin, and the distance from sample sites to the stream source. Three‐way analysis of covariance (ANCOVA) tests with date, site type, and sampling location as main effects were used to explore differences in macroinvertebrate metrics using median substrate size, percent hay/pasture area, and stream depth as covariates. The covariates significantly improved model fit and showed that multiple contributing factors influence community composition. Local impacts were greatest at sites where cows had access, probably because of sedimentation and embeddedness in the substrate. Differences between the upstream and the adjacent and downstream locations were not as great as expected, perhaps because upstream recolonization was reduced by agricultural impacts or because of differences in the intensity or proximity of agriculture to riparian areas in the watershed. The results underscore the importance of both local and watershed factors in controlling stream community composition.  相似文献   
15.
Cultural heritage is being addressed by a number of charters and conventions and it is clear that its consideration within decision-making processes is progressively becoming a real challenge, both for developers and public authorities. Against this background, this paper reviews the environmental assessment framework developed by the European Community, as this should increasingly influence decision making about cultural heritage in an urban setting. The legislative framework for access to environmental information is also reviewed because of its relevance to the decision-making process.The Directives on Environmental Impact Assessment and Strategic Environmental Assessment both require a consideration of cultural heritage in decision making. This requirement can go some way to addressing the paradox in the European Community's position whereby the community wishes to conserve and enhance its own cultural identity whilst, at the same time, cultural heritage is usually defined at a local level. The present paper suggests that, given their flexibility, the two European Community directives on environmental assessment constitute a promising opportunity to address this seeming paradox, but that there is a significant gap between legal obligations and the methodological tools to meet them.  相似文献   
16.
企业开展HSE危害识别及风险评估的现状与对策   总被引:1,自引:0,他引:1  
结合本单位建立与实施HSE管理体系实际,分析了企业开展危害识别与风险评估中常见的问题,提出了解决问题的初步方法。  相似文献   
17.
分析江汉平原粮食生产的优势与问题,运用商品经济的观念,提出改革开放新形势下加快江汉平原粮食开发的设想,即依托市场,按照价值规律,科学地调整种植业比例和粮食种类结构,发展优质品种,扩大优化模式及采用高新技术等,通过优质、高产、高效,促进江汉平原粮食生产的发展。  相似文献   
18.
19.
生态系统服务功能及其价值核算   总被引:20,自引:4,他引:16  
生态系统服务功能是指生态系统服务与生态系统功能的综合,指生态系统与生态过程所形成及所维持的人类赖以生存的自然环境条件与效用,生态系统服务功能对于人类生存发展具有重要的价值,应该在社会经济体系中得以体现,本文探讨了生态系统服务功能的类型,价值核算方法与理论及其应用研究在完善国民经济核算体系、促进可持续发展等方面的重要意义,并对今后发展进行了展望。  相似文献   
20.
On-going population growth and resulting domestic demand for water require rapid and effective decision-making as regards groundwater management and control of the various sources of salinization and pollution in Coastal aquifers. Sustainability of water resources for utilization by future generations must therefore be a high priority, not only for the purpose of fulfilling needs for water usage but also for bringing people into harmony with their ambient natural environment.The objective of this paper is to propose an empirical approach for prioritization of the needs involved for sustainable aquifer management. The approach involves a schematic format to:(1) develop a global understanding of an aquifer's hydrological and environmental properties in order to delineate appropriate eco-hydrological scenarios and recommend corresponding operational management activities; and(2) emphasize the importance of educating and increasing the awareness of the population involved as to the need for and viability of socially acceptable measures for sustainable management of groundwater and other resources.The psychologist Abraham Maslow utilized a pyramid to illustrate that until people's most basic needs were fulfilled, higher levels of needs would remain irrelevant. This paper postulates a comparable pyramid prioritizing hydrological needs required for progressing towards sustainable groundwater resources. Two sub-regions of Israel's Coastal aquifer in the Sharon region have been presented as representative areas, each characterized by different stress of exploitation. In assessing these sub-regions situation, specific measures have been recommended for achieving and/or maintaining sustainable groundwater resources in light of the ambient environment, and the level of the population on the pyramidal hierarchy of groundwater needs.  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