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   2089篇
  免费   35篇
  国内免费   16篇
安全科学   71篇
废物处理   71篇
环保管理   359篇
综合类   336篇
基础理论   519篇
环境理论   5篇
污染及防治   519篇
评价与监测   151篇
社会与环境   92篇
灾害及防治   17篇
  2023年   20篇
  2022年   26篇
  2021年   29篇
  2020年   26篇
  2019年   27篇
  2018年   46篇
  2017年   58篇
  2016年   53篇
  2015年   52篇
  2014年   68篇
  2013年   153篇
  2012年   84篇
  2011年   126篇
  2010年   89篇
  2009年   105篇
  2008年   108篇
  2007年   131篇
  2006年   99篇
  2005年   80篇
  2004年   86篇
  2003年   81篇
  2002年   89篇
  2001年   36篇
  2000年   28篇
  1999年   22篇
  1998年   23篇
  1997年   26篇
  1996年   20篇
  1995年   29篇
  1994年   30篇
  1993年   14篇
  1992年   18篇
  1991年   18篇
  1990年   14篇
  1989年   14篇
  1988年   19篇
  1987年   14篇
  1986年   16篇
  1985年   9篇
  1984年   8篇
  1983年   12篇
  1982年   13篇
  1981年   10篇
  1980年   8篇
  1979年   10篇
  1978年   7篇
  1976年   6篇
  1974年   6篇
  1955年   5篇
  1954年   8篇
排序方式: 共有2140条查询结果,搜索用时 15 毫秒
21.
22.
The relationship between land-use induced changes in production ecology and avifauna diversity was analysed using a GIS land cover dataset on a 0.25 km × 0.25 km grid covering Austria's national territory. Considering only aboveground processes, the “human appropriation of net primary production” (HANPP = potential NPP − NPPt), actual NPP (NPPact), harvest (NPPh) and NPPt (= NPPact − harvest) were recalculated based on existing datasets. Elevation as well as indicators of land cover heterogeneity and landscape heterogeneity were also considered. Correlation analyses were performed between these potential determinants of avifauna diversity and breeding bird species richness data as well as the percentage of endangered breeding birds included in the Austrian red list. Four spatial scales—0.25 km × 0.25 km, 1 km × 1 km, 4 km × 4 km and 16 × 16 km, were analysed. It was shown that breeding bird species richness was more strongly correlated with production ecological indicators and elevation than with heterogeneity indicators. A residual analysis in which the effect of elevation (a proxy for climate) on species richness and its potential determinants was removed confirmed the importance of the availability of trophic energy (NPP) for bird diversity patterns. The results support the species-energy hypothesis, thus confirming the notion that HANPP could be a useful pressure indicator for biodiversity loss.  相似文献   
23.
24.
25.
26.
27.
28.
In situ chemical fixation represents a promising and potentially cost‐effective treatment alternative for metal‐contaminated soils. This article presents the findings of the use of iron‐bearing soil amendments to reduce the leachability and bioaccessibility of arsenic in soils impacted by stack fallout from a zinc smelter. The focus of this investigation was to reduce the lead bioaccessibility of the soils through addition with phosphorus‐bearing amendments. However, as phosphorus addition was expected to increase arsenic mobility, the fixation strategy also incorporated use of iron‐bearing amendments to offset or reverse these effects. The findings of this investigation demonstrated that inclusion of iron‐bearing chemicals in the amendment formulation reduced arsenic leachability and bioaccessibility without compromising amendment effectiveness for reducing lead bioaccessibility. These results suggest that in situ chemical fixation has the potential to be an effective strategy for treatment of the impacted soils. © 2003 Wiley Periodicals, Inc.  相似文献   
29.
Water disputes in the Middle East are not a new phenomenon. For the first time, however, three parties in the region, Jordan, Israel, and the PLO for the benefit of the Palestinian Authority have concluded a "regional water agreement" within the framework of the Multilateral Peace talks. For the first time, the rationale behind the agreement is being made public by the author, who was the "neutral" facilitator of the negotiations. The article discusses some of the main elements, including issues related to water scarcity as a driving force of conflicts; application of a "track-two diplomatic" approach; some lessons learned; as well as some ethical questions related to international negotiation.  相似文献   
30.
ABSTRACT: On May 19, 1993, a jury in the U.S. District Court for the Western District of New York found Southview Farm and Richard H. Popp guilty of violating the Clean Water Act on five occasions. The violations were the result of storm water runoff from a site used for disposal of dairy cattle manure from an unpermitted concentrated animal feeding operation. The presiding District Court judge later dismissed the jury verdict, and subsequently a U.S. Court of Appeals for the Second Circuit reversed the dismissal. The Court of Appeals concluded that the discharges were not exempt as agricultural storm water discharges, and that the manure spreaders involved were point sources. Because the use of animal manures in crop production activities will result, unavoidably, in the discharge of some pollutants to adjacent surface waters, a rational and universally applicable basis is needed to determine when such discharges are point versus nonpoint source. Current statutes and regulations do not delineate clearly such a boundary. To address this lack of specificity, I propose that application rates be based on recommended crop nutrient 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