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   27609篇
  免费   226篇
  国内免费   152篇
安全科学   598篇
废物处理   1462篇
环保管理   3844篇
综合类   4243篇
基础理论   7503篇
环境理论   14篇
污染及防治   6189篇
评价与监测   2112篇
社会与环境   1881篇
灾害及防治   141篇
  2022年   151篇
  2021年   149篇
  2020年   127篇
  2019年   161篇
  2018年   1670篇
  2017年   1583篇
  2016年   1547篇
  2015年   445篇
  2014年   458篇
  2013年   1578篇
  2012年   1028篇
  2011年   2042篇
  2010年   1267篇
  2009年   1205篇
  2008年   1580篇
  2007年   1963篇
  2006年   754篇
  2005年   616篇
  2004年   608篇
  2003年   655篇
  2002年   610篇
  2001年   615篇
  2000年   468篇
  1999年   291篇
  1998年   245篇
  1997年   231篇
  1996年   245篇
  1995年   254篇
  1994年   246篇
  1993年   232篇
  1992年   247篇
  1991年   227篇
  1990年   229篇
  1989年   191篇
  1988年   163篇
  1987年   150篇
  1986年   179篇
  1985年   171篇
  1984年   189篇
  1983年   192篇
  1982年   184篇
  1981年   184篇
  1980年   169篇
  1979年   161篇
  1978年   111篇
  1977年   130篇
  1974年   117篇
  1973年   92篇
  1972年   109篇
  1971年   97篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
361.
Dedicated to Prof. Dr. A. Buchs, University of Geneva, on the occasion of his 60th birthday.  相似文献   
362.
363.
364.
365.
Prenatal diagnosis of the cerebro-hepato-renal (Zellweger) syndrome has been performed in 10 pregnancies at risk by measuring both the activity of acyl CoA: dihydroxyacetonephosphate acyltransferase (DHAP-AT) and the de novo plasmalogen biosynthesis, either in cultured amniotic fluid cells or in fibroblasts cultured from a chorionic villus biopsy. In 7 of the pregnancies both tests indicated no abnormality. All 7 continued to term and normal infants were delivered. However, in amniotic fluid cells from 2 fetuses affected by Zellweger syndrome unequivocal differences from control values were found. The activity of DHAP-AT was clearly deficient and the de novo plasmalogen biosynthesis was impaired. In one pregnancy at risk prenatal diagnosis was performed during the first trimester by measuring both the DHAP-AT activity and the de novo plasmalogen biosynthesis in fibroblasts cultured from a chorionic villi biopsy. From the deficient DHAP-AT activity and the impaired de novo plasmalogen biosynthesis it was concluded that the fetus was affected. This was confirmed biochemically after induced abortion. It can be concluded that measurement of the DHAP-AT activity and the de novo plasmalogen biosynthesis provides convenient methods for the early prenatal detection of Zellweger syndrome.  相似文献   
366.
367.
368.
This article reports the results of a retrospective study designed to examine the responses of couples to genetic amniocentesis and subsequent therapeutic abortions due to birth defects. Fourteen women and 12 men were interviewed by experienced interviewers using a structured format designed by the authors, and each interview was audiotaped for later rating. The 5 raters (all women) were instructed to independently rate each interview using forms designed by the authors to elicit information about many aspects of the participant's individual responses as well as perceptions of spouse's responses to the process of pregnancy, amniocentesis, therapeutic abortion, and sequelae. Ratings of all 5 raters were conjoined and an homogeneous narrative was constructed for each interview. Results indicate, in general, that the respondent couples coped well with this experience. In fact 70 per cent of the respondent couples described their marital relationships as becoming closer as a result of their experience. Only a few participants reported long-term deleterious effects. Most couples coped by relying on relatives, friends, and occasionally, professional counsellors. In addition, most participants in this study suggested ways to improve the medical and psychological aspects of this experience.  相似文献   
369.
370.
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