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   13608篇
  免费   88篇
  国内免费   45篇
安全科学   222篇
废物处理   970篇
环保管理   1939篇
综合类   1587篇
基础理论   3923篇
环境理论   4篇
污染及防治   2726篇
评价与监测   1255篇
社会与环境   1066篇
灾害及防治   49篇
  2023年   29篇
  2022年   35篇
  2021年   56篇
  2020年   47篇
  2019年   51篇
  2018年   1541篇
  2017年   1442篇
  2016年   1291篇
  2015年   247篇
  2014年   156篇
  2013年   315篇
  2012年   635篇
  2011年   1549篇
  2010年   878篇
  2009年   801篇
  2008年   1058篇
  2007年   1423篇
  2006年   212篇
  2005年   164篇
  2004年   193篇
  2003年   209篇
  2002年   227篇
  2001年   135篇
  2000年   93篇
  1999年   60篇
  1998年   64篇
  1997年   58篇
  1996年   51篇
  1995年   54篇
  1994年   53篇
  1993年   37篇
  1992年   35篇
  1991年   48篇
  1990年   24篇
  1989年   29篇
  1988年   23篇
  1987年   22篇
  1986年   15篇
  1985年   23篇
  1984年   28篇
  1983年   29篇
  1982年   29篇
  1981年   34篇
  1980年   16篇
  1979年   19篇
  1978年   9篇
  1977年   11篇
  1970年   9篇
  1966年   8篇
  1960年   8篇
排序方式: 共有10000条查询结果,搜索用时 49 毫秒
71.
欧洲的氮状况   总被引:5,自引:0,他引:5  
欧洲(不包括前苏联)的氮收支表明,欧洲氮循环加速的三个主要驱动力是肥料生产(14MtN/a)、矿物燃料燃烧及其它工业(3.3MtN/a)和各种产品中的氮输入(7.6MtN/a).本文估计了欧洲粮食、能源和工业产品系统中活性氮元素的各种泄漏,评估了它们对人类健康及水陆生态系统的影响.考虑到氮流转中的可能后果,未来欧洲有关封闭氮循环和减少活性氮泄漏的环境政策措施最好集中于三个主要驱动力.在确定氮排放上限和制定氯流控制的综合政策方面,如肥料使用、输入和氮水平,临界负载可能是非常有用的工具.  相似文献   
72.
Gamergates (i.e. mated reproductive workers) are mostly known from ant species within the Ponerinae. We report here the discovery of gamergates in two species of the subfamily Myrmicinae. Until now, mated reproductive females in colonies of myrmicine species have been considered morphologically distinct from the worker caste. However, in two species of the myrmicine Metapone (Metapone madagascarica and a newly discovered, not yet described Metapone species) all workers have six ovarioles and a spermatheca; and some of them are mated. There are no morphological differences between mated and non-mated workers. Field observations and laboratory studies indicate that colonies of the Metapone species can reproduce with gamergates only.  相似文献   
73.
Although amphibians are highly vocal, they generally emit only a limited number of acoustic communication signals. We report here the extraordinarily rich vocal repertoire of Amolops tormotus, a ranid species in China. These frogs produce countless vocalizations, some of which share features of birdsong or primate calls, e.g., ultrasonic frequency components, multiple upward and downward FM sweeps, and sudden onset and offset of selective harmonic components within a call note. Frame-by-frame video analysis of the frog's calling behavior suggests the presence of two pairs of vocal sacs that may contribute to the remarkable call-note complexity in this species. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-002-0335-x.  相似文献   
74.
In this study, an inventory of air pollutant emission estimates from major air polluting sources in Turkey for period between 1985 and 2005 with 5-year intervals were estimated. Inventory covers anthropogenic sources of five major air pollutants of particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides and non-methane volatile organic compounds. Their break-down with respect to main activity sectors were shown and their distribution by the largest industrial source categories were worked out as annual estimates. This inventory and its analysis point to serious environmental implications of air pollutants and a need to develop a policy plan for reducing these emissions.  相似文献   
75.
76.
77.
This paper presentse-SEREM (Smart Emission ReductionEstimation Manual), a cost-free, easilyaccessed and updated, web-based manual forestimating emission reductions from Joint Implementation (JI) andClean Development Mechanism (CDM) projects. e-SEREM's main functions arethe selection of a benchmark for a specificproject type in the power or heat sectorand the calculation of the annual andcumulative emission reductions accrued bythis project for its crediting lifetime.e-SEREM was developed in order to test itsapplicability and practicality in assistingproject developers and evaluators toelaborate baselines easily and calculatethe emission credits earned by candidate JIor CDM projects hosted in several countries.  相似文献   
78.
Independent teams undertook environmental monitoring of particular concentrations of major construction projects forming part of Hong Kong’s U.S. $20 billion airport infrastructure programme located in dense urban areas. The team combination of environmental specialists with experienced civil engineers enabled pragmatic mitigation measures to be developed and accepted by the construction personnel with the result that potentially significant adverse impacts were averted. The authors discuss the mechanism and success of this innovative approach.  相似文献   
79.
80.
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