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   1356篇
  免费   32篇
  国内免费   19篇
安全科学   54篇
废物处理   69篇
环保管理   135篇
综合类   305篇
基础理论   234篇
环境理论   1篇
污染及防治   357篇
评价与监测   152篇
社会与环境   80篇
灾害及防治   20篇
  2023年   10篇
  2022年   16篇
  2021年   33篇
  2020年   17篇
  2019年   17篇
  2018年   40篇
  2017年   49篇
  2016年   46篇
  2015年   31篇
  2014年   59篇
  2013年   94篇
  2012年   48篇
  2011年   84篇
  2010年   56篇
  2009年   64篇
  2008年   78篇
  2007年   69篇
  2006年   52篇
  2005年   54篇
  2004年   62篇
  2003年   69篇
  2002年   51篇
  2001年   53篇
  2000年   31篇
  1999年   25篇
  1998年   16篇
  1997年   12篇
  1996年   7篇
  1995年   14篇
  1994年   10篇
  1993年   16篇
  1992年   16篇
  1991年   3篇
  1990年   5篇
  1989年   6篇
  1988年   6篇
  1986年   5篇
  1985年   8篇
  1984年   6篇
  1983年   8篇
  1982年   8篇
  1981年   5篇
  1980年   2篇
  1979年   2篇
  1976年   2篇
  1970年   2篇
  1966年   2篇
  1963年   4篇
  1962年   6篇
  1961年   3篇
排序方式: 共有1407条查询结果,搜索用时 156 毫秒
81.
Between May 1987 and November 1988, 505 early amniocentesis within the 15th week of gestation were performed at the First Department of Obstetrics and Gynaecology,‘L. Mangiagalli’ of the University of Milan and at the Department of Obstetrics and Gynaecology of ‘Gaslini’ hospital in Genoa. A total number often abnormal fetal karyotypes were diagnosed. In addition, one case of pseudomosaicism (not confirmed on fetal blood) and one case of osteogenesis imperfecta type II (observed at ultrasound examination) were also detected. Eleven pregnancies were therefore terminated because of an abnormal fetus. Out of 494 pregnancies (excluding terminated pregnancies) there were 16 fetal losses within the 28th week; ten of these occurred in the 2 weeks following the procedure. There were 475 live-births, of which 447 were term deliveries and the other 28 deliveries occurred before the 37th week of gestation.  相似文献   
82.

Objective

Genomics Quality Assessment has provided external quality assessments (EQAs) for preimplantation genetic testing (PGT) for 12 years for eight monogenic diseases to identify sub-optimal PGT strategies, testing and reporting of results, which can be shared with the genomics community to aid optimised standards of PGT services for couples.

Method

The EQAs were provided in two stages to mimic end-to-end protocols. Stage 1 involved DNA feasibility testing of a couple undergoing PGT and affected proband. Participants were required to report genotyping results and outline their embryo testing strategy. Lymphoblasts were distributed for mock embryo testing for stage 2. Submitted clinical reports and haplotyping results were assessed against peer-ratified criteria. Performance was monitored to identify poor performance.

Results

The most common testing methodology was short tandem repeat linkage analysis (59%); however, the adoption of single nucleotide polymorphism-based platforms was observed and a move from blastomere to trophectoderm testing. There was a variation in testing strategies, assigning marker informativity and understanding test limitations, some clinically unsafe. Critical errors were reported for genotyping and interpretation.

Conclusion

EQA provides an overview of the standard of preimplantation genetic testing-M clinical testing and identifies areas of improvement for accurate detection of high-risk embryos.  相似文献   
83.
84.
85.
This paper examines the nature of the economic costs and risks involved in brownfield versus greenfield redevelopment in the Greater Toronto Area (Ontario, Canada) from a private sector perspective, and assesses the potential effectiveness of different policies and programmes designed to attenuate associated costs and risks. Through interviews, case-studies and an analysis of hypothetical development scenarios, it has been found that the perception that brownfield redevelopment is less cost-effective and entails greater risks than greenfield development, on the part of the private sector, is true for industrial projects in the province, but not for residential ones, which were found to be feasible, given the assumptions of the present study. Furthermore, the study has found that the attractiveness of residential brownfield projects can increase considerably with minor policy changes, but that promoting industrial redevelopment will require a more vigorous approach that employs a variety of environmental policy and economic development measures.  相似文献   
86.
87.
88.
 Liquid phase hydrocarbon oxidation is one of the principal routes towards industrial organic chemicals. However, low product selectivity and associated by-product formation are major problems in several oxidation processes. As a result of the increasingly stringent environmental regulations, the development of oxidation catalysts has been a major challenge in the last decade. An overview of novel selective and clean oxidation catalysts and processes is presented. Received: 27 July 1998 / Accepted: 8 September 1998  相似文献   
89.
90.
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