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   16611篇
  免费   207篇
  国内免费   143篇
安全科学   461篇
废物处理   621篇
环保管理   2257篇
综合类   3159篇
基础理论   4189篇
环境理论   11篇
污染及防治   4124篇
评价与监测   1034篇
社会与环境   974篇
灾害及防治   131篇
  2022年   151篇
  2021年   159篇
  2020年   126篇
  2019年   145篇
  2018年   224篇
  2017年   270篇
  2016年   364篇
  2015年   301篇
  2014年   424篇
  2013年   1402篇
  2012年   510篇
  2011年   680篇
  2010年   548篇
  2009年   603篇
  2008年   669篇
  2007年   707篇
  2006年   654篇
  2005年   518篇
  2004年   507篇
  2003年   517篇
  2002年   446篇
  2001年   548篇
  2000年   427篇
  1999年   246篇
  1998年   204篇
  1997年   195篇
  1996年   209篇
  1995年   219篇
  1994年   211篇
  1993年   207篇
  1992年   218篇
  1991年   204篇
  1990年   205篇
  1989年   177篇
  1988年   152篇
  1987年   132篇
  1986年   157篇
  1985年   160篇
  1984年   161篇
  1983年   162篇
  1982年   156篇
  1981年   162篇
  1980年   151篇
  1979年   145篇
  1978年   109篇
  1977年   121篇
  1974年   109篇
  1973年   91篇
  1972年   107篇
  1971年   88篇
排序方式: 共有10000条查询结果,搜索用时 890 毫秒
321.
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   
322.
323.
324.
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   
325.
326.
327.
328.
329.
330.
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