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   20312篇
  免费   314篇
  国内免费   189篇
安全科学   700篇
废物处理   732篇
环保管理   3293篇
综合类   3563篇
基础理论   5203篇
环境理论   18篇
污染及防治   4784篇
评价与监测   1243篇
社会与环境   1102篇
灾害及防治   177篇
  2023年   114篇
  2022年   173篇
  2021年   177篇
  2020年   166篇
  2019年   197篇
  2018年   308篇
  2017年   358篇
  2016年   491篇
  2015年   382篇
  2014年   518篇
  2013年   1696篇
  2012年   673篇
  2011年   899篇
  2010年   693篇
  2009年   786篇
  2008年   864篇
  2007年   890篇
  2006年   832篇
  2005年   677篇
  2004年   652篇
  2003年   623篇
  2002年   555篇
  2001年   617篇
  2000年   508篇
  1999年   303篇
  1998年   267篇
  1997年   241篇
  1996年   265篇
  1995年   286篇
  1994年   275篇
  1993年   268篇
  1992年   260篇
  1991年   237篇
  1990年   234篇
  1989年   208篇
  1988年   179篇
  1987年   163篇
  1986年   194篇
  1985年   190篇
  1984年   198篇
  1983年   203篇
  1982年   205篇
  1981年   202篇
  1980年   180篇
  1979年   159篇
  1978年   135篇
  1977年   135篇
  1974年   114篇
  1972年   114篇
  1971年   97篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
771.
772.
773.
774.
Identifying and communicating uncertainty is core to effective environmental assessment (EA). This study evaluates the extent to which uncertainties are considered and addressed in Canadian EA practice. We reviewed the environmental protection plans, follow-up programs, and panel reports (where applicable) of 12 EAs between 1995 and 2012. The types of uncertainties and levels of disclosure varied greatly. When uncertainties were acknowledged, practitioners adopted five different approaches to address them. However, uncertainties were never discussed or addressed in depth. We found a lack of suitable terminology and consistency in how uncertainties are disclosed, reflecting the need for explicit guidance, and we present recommendations for improvement. Canadian Environmental Impact Statements are not as transparent with respect to uncertainties as they should be, and uncertainties in EA need to be better considered and communicated.  相似文献   
775.
While many studies and reviews into the practices conducted by industry and academia to recycle and remanufacture carbon fibre-reinforced plastic (CFRP) exist, to date no investigation exists which regards the correctness of the use of the terms recycling and remanufacturing. As such, this paper seeks to analyse the CFRP reuse industry’s attempt to recycle and remanufacture manufacturing waste CFRP and end-of-life (EOL) CFRP with an emphasis on the terminology used to describe these practices. Firstly, this paper presents a justification of the importance of using EOL terminology correctly; outlining the benefits and problems associated with using the correct and incorrect terminology. This paper finds that in the case of CFRP remanufacturing, terminology is being applied incorrectly and in the case of CFRP recycling, particular care should be taken when applying the term recycled to CFRP or stating that CFRP has been recycled. Further, this paper proposes new terminology (in keeping with EU directives) which could be adopted by industry and academia working in this area. This paper also finds that in the case of remanufacture, CFRP is incapable of being remanufactured.  相似文献   
776.
Journal of Material Cycles and Waste Management - Several types of industrial solid waste have been used as byproducts in the construction and materials industries. Some of the applications seem to...  相似文献   
777.
In contradistinction to the ideas of Lynn White and others who have long suggested that the Judeo-Christian tradition fosters a ‘dominion over nature’ ethos, a number of scholars have recently argued that there has been a ‘greening of Christianity’. Largely missing from this debate is strong evidence at the individual level as to whether Christians have in fact adopted deeper environmental concerns over time. This study provides such evidence through an examination of longitudinal data from Gallup’s annual surveys on the environment. The analysis reveals little evidence that Christians have expressed more environmental concern over time. In fact, across many measures, Christians tend to show less concern about the environment. This pattern holds across Catholic, Protestant and other Christian denominations and for differing levels of religiosity. These findings support a conclusion that there has not been a discernible ‘greening of Christianity’ among the American public.  相似文献   
778.
Quantifying surface water shortages in arid and semiarid agricultural regions is challenging because limited water supplies are distributed over long distances based on complex water management systems constrained by legal, economic, and social frameworks that evolve with time. In such regions, the water supply is often derived in a climate dramatically different from where the water is diverted to meet agricultural demand. The existing drought indices which rely on local climate do not portray the complexities of the economic and legal constraints on water delivery. Nor do these indices quantify the shortages that occur in drought. Therefore, this research proposes a methodological approach to define surface water shortages in irrigated agricultural systems using a newly developed index termed the Surface Water Delivery Index (SWDI). The SWDI can be used to uniformly quantify surface water deficits/shortages at the end of the irrigation season. Results from the SWDI clearly illustrate how water shortages in droughts identified by the existing indices (e.g., SPI and PDSI) vary strongly both within and between basins. Some surface water entities are much more prone to water shortages than other entities based both on their source of water supply and water right portfolios.  相似文献   
779.
Variability and trends in water‐year runoff efficiency (RE) — computed as the ratio of water‐year runoff (streamflow per unit area) to water‐year precipitation — in the conterminous United States (CONUS) are examined for the 1951 through 2012 period. Changes in RE are analyzed using runoff and precipitation data aggregated to United States Geological Survey 8‐digit hydrologic cataloging units (HUs). Results indicate increases in RE for some regions in the north‐central CONUS and large decreases in RE for the south‐central CONUS. The increases in RE in the north‐central CONUS are explained by trends in climate, whereas the large decreases in RE in the south‐central CONUS likely are related to groundwater withdrawals from the Ogallala aquifer to support irrigated agriculture.  相似文献   
780.
Intensifying global trade will result in increased numbers of plant pest and pathogen species inadvertently being transported along with cargo. This paper examines current mechanisms for prevention and management of potential introductions of forest insect pests and pathogens in the European Union (EU). Current European legislation has not been found sufficient in preventing invasion, establishment and spread of pest and pathogen species within the EU. Costs associated with future invasions are difficult to estimate but past invasions have led to negative economic impacts in the invaded country. The challenge is combining free trade and free movement of products (within the EU) with protection against invasive pests and pathogens. Public awareness may mobilise the public for prevention and detection of potential invasions and, simultaneously, increase support for eradication and control measures. We recommend focus on commodities in addition to pathways, an approach within the EU using a centralised response unit and, critically, to engage the general public in the battle against establishment and spread of these harmful pests and pathogens.  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