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   687篇
  免费   9篇
  国内免费   7篇
安全科学   18篇
废物处理   36篇
环保管理   66篇
综合类   159篇
基础理论   138篇
环境理论   1篇
污染及防治   193篇
评价与监测   54篇
社会与环境   33篇
灾害及防治   5篇
  2023年   9篇
  2022年   19篇
  2021年   17篇
  2020年   14篇
  2019年   11篇
  2018年   20篇
  2017年   25篇
  2016年   32篇
  2015年   20篇
  2014年   28篇
  2013年   53篇
  2012年   47篇
  2011年   36篇
  2010年   33篇
  2009年   39篇
  2008年   37篇
  2007年   34篇
  2006年   38篇
  2005年   19篇
  2004年   21篇
  2003年   27篇
  2002年   22篇
  2001年   8篇
  2000年   4篇
  1998年   4篇
  1997年   6篇
  1995年   4篇
  1994年   9篇
  1993年   3篇
  1992年   2篇
  1991年   4篇
  1990年   4篇
  1989年   5篇
  1987年   2篇
  1985年   3篇
  1983年   2篇
  1979年   2篇
  1978年   3篇
  1964年   2篇
  1959年   2篇
  1957年   2篇
  1925年   2篇
  1924年   2篇
  1923年   2篇
  1921年   3篇
  1920年   1篇
  1919年   1篇
  1918年   2篇
  1917年   1篇
  1914年   1篇
排序方式: 共有703条查询结果,搜索用时 15 毫秒
41.
42.
Recent studies have shown that there are many effects of climate change on aeroallergens, and thus on allergic diseases in humans. In the Mediterranean region, despite the importance of the olive tree for production, there is high allergenicity of olive pollen and related risks to human health. Aerobiological sampling techniques can be used to analyse the pollinosis phenomenon through determination of mean daily pollen concentrations per cubic metre of air. The present study was carried out from 1999 to 2008 in 16 olive-growing areas in Italy, to update the information on the pollinosis characteristics of Olea europaea in the study areas. The analysis of the average flowering season over the study period highlights a temporal scaling of pollen in the atmosphere that depends on the different climatic characteristics. This is mainly dependent on temperature, and in part, determined by latitude. Generally, the levels of O. europaea pollen in the atmosphere are higher from mid-April to the end of June, with the period of greatest risk to human health due to this olive pollen in this area currently limited primarily to the last 10 days of May. However, the pollen season can move, depending on the climate scenario considered, and data here can be used to determine potential time shifts in pollinosis that might cause more precocious asthma and allergy problems. The allergy season for this type of pollen might be significantly precocious in future decades (20–30 days earlier in the year), which will impact on the severity and duration of allergies attributable to olive tree pollen.  相似文献   
43.
44.
45.
46.
47.
Animal wastes from intensive farming are generally collected for field fertilisation. They may contain drugs that can become soil pollutants. To evaluate the possible effects of such contamination in terrestrial systems, sulphadimethoxine has been subjected to laboratory tests (in vitro, synthetic medium, and soil) using seeds of barley (Hordeum distichum L.). The drug suppressed normal post-germinative development and growth of roots and leaves in both test conditions; this effect was dependent on the bioaccumulation rate, which was higher on synthetic medium than in soil. Bioaccumulation was higher in roots than foliage and this was markedly evident in soil and, in particular, in soils with a low humus content. The environmental risk of sludge application on soils and the possible contamination of food chains are discussed.  相似文献   
48.
49.
Basic principles of reducing exposure to electromagnetic fields are reviewed in this article. Measures to reduce exposure can be divided into organisational/administrative and technical/engineering actions. Both strategies are briefly analysed and the basic principles of the theory of shielding are presented. A definition of shielding effectiveness (SE) is given, and the results from the general Transmission Lines Theory are presented. Practical situations of shielding static and time-varying electric and magnetic fields are discussed on the basis of the physical properties of the fields and of the shield.  相似文献   
50.
The Lagoon of Venice is a transitional environment suffering from industrial, urban and agricultural impact. Recently the mechanical clam fishing, preventing a regular deposition of sediments has made sampling of cores suitable for radiodating very problematic. Therefore, in this study, in order to assess temporal and spatial trends of contamination, the same sampling scheme was repeated three times over a 12-year period. The concentrations of PCBs, PAHs and organochlorine pesticides were measured in the uppermost 5 cm of sediments collected in 25 sites in the central portion of the lagoon during three campaigns conducted in 1987, 1993 and 1998. Analytical results, validated statistically, indicated that, while PCB and pesticide concentrations tend to decrease during the considered period of time, PAH do not, showing that the input rate of these compounds to the lagoon environment is still important. A spatial trend of pollution was also found in the lagoon for PCBs and pesticides, which decrease from the sources, namely the industrial zone and the mouths of rivers, to areas closer to the sea: a reduction up to 80% and 90%, respectively, was monitored. PAH contamination, originating chiefly from incomplete combustion of fossil fuels, as inferred from ratios of congeners, was mainly located around the historical center of Venice, where most of the boat traffic is concentrated and has an increasing trend.  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