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   90篇
  免费   0篇
  国内免费   1篇
环保管理   6篇
综合类   59篇
基础理论   14篇
污染及防治   11篇
社会与环境   1篇
  2023年   2篇
  2020年   5篇
  2019年   2篇
  2018年   4篇
  2017年   7篇
  2016年   3篇
  2015年   4篇
  2014年   5篇
  2013年   6篇
  2012年   3篇
  2011年   3篇
  2010年   3篇
  2009年   2篇
  2008年   5篇
  2007年   3篇
  2006年   3篇
  2005年   2篇
  2004年   3篇
  2003年   1篇
  2002年   3篇
  2001年   1篇
  1999年   1篇
  1998年   1篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1980年   2篇
  1979年   2篇
  1973年   1篇
  1971年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有91条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
Noninvasive prenatal testing (NIPT) using cell-free DNA is being offered to an increasing number of women. Comprehensive pre-test counseling is complicated by emerging information about the benefits and limitations of testing, as well as the potential to detect incidental findings. Genetic counselors are trained to facilitate informed decision-making; however, not all centers have access to these professionals. To aid in the informed consent process, we have summarized key points to be included in discussions with patients who are considering NIPT. © 2015 John Wiley & Sons, Ltd.  相似文献   
66.
67.
Toxicity tests using adult specimens of Jenynsia multidentata were carried out during 96 hours in order to determine the lethal concentration (LC50) of endosulfan. Histological alterations were determined in gills and liver. Gill damage was quantified as secondary lamellae thickness. The 96 hr LC50 values were significantly different between males (0.719 μ g.L? 1) and females (1.317 μg.L? 1). The sex difference was attributed to the dimorphism in the lipid content in females (2.16%) and males (1.79%). Histological alterations in gills included hypertrophy and lifting of the epithelium of the secondary lamellae and aneurisms. These alterations caused a significant increase of the secondary lamellae thickness in treatment versus control fish. Finally, reversible histological alterations (such as hydropic degeneration and dilation of sinusoids) were observed in the liver of exposed fish as well as an irreversible change such as necrosis at the highest concentrations.  相似文献   
68.
69.
Taxonomic composition, biomass, primary production and growth rates of the phytoplankton community were studied in two stations in the NW Adriatic Sea on a seasonal basis, in areas characterized by differing hydrological and trophic conditions. The main differences between the two stations were quantitative rather than qualitative, most phytoplankton species being common to both stations. The effects of differing nutrient concentrations and plume spreading were evident. Biomass and primary production rates were significantly higher in the coastal station (S1), and the phytoplankton distribution in the water column was markedly stratified in S1 and more even in the offshore station (S3). However, chlorophyll a specific production, potential growth rate and production efficiencies were very similar in both stations, even when phosphorus concentrations were limiting. A discrepancy between potential and actual growth rate was observed: as a feature common to both stations, comparisons between potential and actual growth rates revealed that little carbon produced by phytoplankton accumulated as algal biomass; therefore, very high loss rates were estimated.  相似文献   
70.
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