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   40102篇
  免费   348篇
  国内免费   227篇
安全科学   876篇
废物处理   1879篇
环保管理   5411篇
综合类   5626篇
基础理论   11762篇
环境理论   22篇
污染及防治   9481篇
评价与监测   2778篇
社会与环境   2645篇
灾害及防治   197篇
  2022年   192篇
  2021年   187篇
  2019年   222篇
  2018年   1889篇
  2017年   1766篇
  2016年   1724篇
  2015年   633篇
  2014年   701篇
  2013年   2184篇
  2012年   1341篇
  2011年   2579篇
  2010年   1818篇
  2009年   1690篇
  2008年   2207篇
  2007年   2622篇
  2006年   1218篇
  2005年   1122篇
  2004年   1078篇
  2003年   1091篇
  2002年   1111篇
  2001年   1266篇
  2000年   882篇
  1999年   567篇
  1998年   456篇
  1997年   444篇
  1996年   454篇
  1995年   493篇
  1994年   453篇
  1993年   406篇
  1992年   421篇
  1991年   380篇
  1990年   381篇
  1989年   420篇
  1988年   352篇
  1987年   302篇
  1986年   279篇
  1985年   313篇
  1984年   302篇
  1983年   333篇
  1982年   328篇
  1981年   274篇
  1980年   246篇
  1979年   272篇
  1978年   230篇
  1977年   196篇
  1976年   201篇
  1975年   192篇
  1974年   172篇
  1973年   172篇
  1972年   198篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Environmental Science and Pollution Research - Legacy (i.e., polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD)) and alternative halogenated flame retardants (HFRs) were...  相似文献   
2.
3.
4.
Journal of Material Cycles and Waste Management - The traditional Chinese medicinal plant Magnolia officinalis has a wide range of applications; including more than 200 kinds of patented Chinese...  相似文献   
5.
6.
7.
8.
9.
The feasibility of using U.K. coal-fired power station waste materials for artificial reef production is being examined. in June, 1989, an experimental artificial reef was constructed in Poole Bay, off the central south coast of the U.K., using three different mixtures of pulverised fuel ash (PFA), flue gas desulphurisation (FGD) gypsum and slurry, stabilized with cement and formed into blocks. Fifty tonnes of 40 × 20 × 20 cm blocks were formed into eight conical reef units replicating three different PFA/gypsum mixtures and one concrete control. the reef structure is 10m below chart datum on a flat sandy sea-bed.

Combustion of coal concentrates the heavy metal content in the resultant ash. the purpose of stabilization of the ash as blocks is twofold: to immobilize heavy metals (or other components) and to provide hard substratum for the attachment of organisms. to examine the effectiveness of this stabilization and hence the environmental compatibility of the block materials, heavy metal (Cd, Cr, Cu, Pb, Mn, Ni, Zn) content of the blocks has been monitored routinely over two years, to determine leaching rates. Sectional profiles indicate partial replacement of calcium content by magnesium. Associated with this there has also been some redistribution of heavy metals. Only in the case of cadmium has there been a detectable loss from the surface of blocks. Chromium and manganese concentrations appear to have increased. the metal content of the reef epibiota (including ascidians, Ascidia mentula; hydroids, Halecium spp.; bryozoans, Bugula spp. and red algae) growing on the ash blocks has been compared to that of epibiota attached to the concrete controls and surrounding sea-bed. to date no evidence of excess bioaccumulation of metals has been detected.

The physical integrity of the ash reef blocks has been maintained. There is evidence that the blocks are increasing in compressive strength.

An indication of the fishery enhancement potential of the experimental structure is given by the presence of eight commercially fished species (crustaceans and molluscs) including lobsters (Homarus gammarus).  相似文献   
10.
In vitro investigations of the influence of lindane and its metabolites were performed on microsomal and mitochondrial ATPases from liver, kidney and brain of rat and mouse. The microsomal Na+-K+-ATPases in rat liver were inhibited by the tested substances. An increase of activity was observed only with 2.5 X 10(-5) M gamma-HCH. Effects on the microsomal Na+-K+-ATPase from kidney and brain of rat were also indicated. The mitochondrial enzyme in rat liver was stimulated by all the compounds tested at concentrations of 10(-4) M - 10(-2) M. The effects on mitochondrial enzymes from kidney and brain varied in dependence on the tested substances. In the microsomes and mitochondria of mouse an influence on the Na+-K+-ATPases similar to the effects on the preparations from organs of rat was evident.  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