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   2124篇
  免费   12篇
  国内免费   6篇
安全科学   11篇
废物处理   80篇
环保管理   109篇
综合类   821篇
基础理论   452篇
污染及防治   459篇
评价与监测   119篇
社会与环境   80篇
灾害及防治   11篇
  2017年   23篇
  2016年   32篇
  2015年   19篇
  2014年   25篇
  2013年   87篇
  2012年   31篇
  2011年   67篇
  2010年   57篇
  2009年   63篇
  2008年   86篇
  2007年   69篇
  2006年   52篇
  2005年   56篇
  2004年   54篇
  2003年   52篇
  2002年   60篇
  2001年   66篇
  2000年   57篇
  1999年   44篇
  1998年   33篇
  1997年   38篇
  1996年   34篇
  1995年   37篇
  1994年   34篇
  1993年   31篇
  1992年   19篇
  1991年   40篇
  1990年   54篇
  1989年   24篇
  1988年   28篇
  1987年   22篇
  1985年   24篇
  1984年   24篇
  1983年   19篇
  1982年   32篇
  1979年   21篇
  1977年   19篇
  1974年   20篇
  1972年   21篇
  1967年   31篇
  1966年   23篇
  1965年   24篇
  1963年   22篇
  1962年   23篇
  1961年   19篇
  1960年   17篇
  1959年   21篇
  1958年   23篇
  1957年   19篇
  1955年   16篇
排序方式: 共有2142条查询结果,搜索用时 15 毫秒
681.
682.
The Andman and Nicobar archipelago comprises of about 556 small and big islands covering an area of 8493 sq. kms in the Bay of Bengal. The very remoteness of these islands from the mainland has preserved their pristine environment and spectacular natural beauty. The Andman and Nicobar Administration is going for major developmental projects to cope with the increasing needs of the people, which ultimately results in significant changes in environmental quality. This paper describes the existing environmental quality around Port Blair city, which will give baseline scenario to assess the environmental impacts due to developments in the future.In order to monitor the air quality of the region, sampling stations were selected based on the locations of various industries and domestic activities. Suspended Particulate Matter (SPM), Sulphur dioxide (SO2) and Nitrogen Oxides (NOx) were monitored for a period of one month during winter season. In addition, micrometeorological data, viz. wind speed and direction were also recorded and analysed to obtain the representative meteorological scenario of the air basin. The monitored values of ambient air quality was found to be within the NAAQ standards of India.Similarly, noise levels were also measured at various locations viz., residential areas, commercial centres, villages, stone quarry sites and construction sites. Noise levels were found to exceed the standards at stone quarry, construction sites and other locations.Water quality studies were carried out with respect to surface and ground water. The various physico- chemical and bacteriological parameters were analysed. It was observed that the physico-chemical parameters of surface and ground water lie within the standards stipulated for Indian subcontinent except for heavy metals which exceed the limits in ground water samples. Bacteriological analysis of sea water and ground water indicate that they are contaminated with faecal matters. Further, the ground water can be used for drinking purposes only after adequate treatment.  相似文献   
683.
684.
使用固相萃取和液相色谱/质谱/质谱,在正离子和负离子模式下,分别分析了46个和14个农药化合物.无需衍生化,就能达到pg水平的分析灵敏度.对于所有农药的化合物,在5 pg—1 ng的范围内具有很好的线性.  相似文献   
685.
Magnetic resonance (MR) imaging was performed at 29 weeks of pregnancy after ultrasonographic detection of an abnormal cleft in the fetal brain. Fetal neuromuscular blockade was induced by pancuronium bromide injected into the umbilical vein under continuous ultrasound (US) guidance. MR images supported the echotomographic diagnosis of schizencephaly improving the visualization of symmetrical broad clefts connecting the lateral ventricles with the subarachnoid space. Schizencephaly was finally confirmed by neonatal US, computed tomography, and MR.  相似文献   
686.
687.
688.
689.
690.
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