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   155篇
  免费   0篇
  国内免费   1篇
安全科学   1篇
废物处理   5篇
环保管理   9篇
综合类   86篇
基础理论   19篇
污染及防治   27篇
评价与监测   4篇
社会与环境   5篇
  2019年   2篇
  2017年   2篇
  2016年   3篇
  2014年   2篇
  2013年   8篇
  2012年   5篇
  2011年   2篇
  2010年   2篇
  2009年   6篇
  2008年   3篇
  2007年   9篇
  2006年   5篇
  2005年   2篇
  2003年   3篇
  2002年   3篇
  2000年   2篇
  1999年   2篇
  1994年   2篇
  1987年   2篇
  1986年   3篇
  1980年   3篇
  1970年   2篇
  1966年   2篇
  1964年   2篇
  1959年   4篇
  1958年   6篇
  1957年   2篇
  1956年   5篇
  1955年   2篇
  1950年   2篇
  1938年   3篇
  1937年   1篇
  1935年   2篇
  1934年   4篇
  1933年   3篇
  1932年   5篇
  1931年   2篇
  1930年   1篇
  1928年   1篇
  1926年   1篇
  1925年   1篇
  1924年   1篇
  1923年   1篇
  1922年   1篇
  1920年   1篇
  1919年   1篇
  1917年   2篇
  1916年   3篇
  1915年   1篇
  1914年   1篇
排序方式: 共有156条查询结果,搜索用时 484 毫秒
1.
2.
3.
4.
5.
厦门西港海水质量对鱼卵胚胎发育畸形率的影响   总被引:3,自引:1,他引:3  
以养殖场培育的花尾胡椒鲷受精卵为实验材料测试了厦门西域5个站位的表层水水样对花尾胡椒鲷受精卵的胚胎发育毒性,并运用GC-MS手段分析了水样中的美国EPA优控的16PAHs组分的含量。结果表明:3号站位(厦门市工业和生活污水主要排放口的外侧)和4号站位(厦门西港的港区)的水样对鱼卵的胚胎发育的毒性最强。8号站位(位于主航道并濒临嵩屿电厂)的水样对鱼卵胚胎发良的毒性次之,1号站位(湾口)和5号站位(内港)的水样对鱼卵的胚胎发育的毒性较小。水样中的PAHs含量分析结果表明,仅用水样中的PAHs含量不能全面地反映水样对鱼卵胚胎发育的毒性。最后,对本实验方法应用于海洋环境生物监测的有效性进行了探讨。  相似文献   
6.
The aggregation of multi-walled carbon nanotubes (MWCNTs) in the aqueous phase not only inhibits their extensive utilization in various aspects but also dominates their environmental fate and transport.The role of surfactants at low concentration in the aggregation of MWCNTs has been studied,however the effect of perfluorinated surfactants at low concentration is uncertain.To understand this interfacial phenomenon,the influences of perfluorooctanoic acid (PFOA),and sodium dodecyl sulfate (SDS) as a control,on MWCNT aggregation in the aqueous phase were examined by the UV absorbency method.Influences of pH and cationic species on the critical coagulation concentration (CCC) value were evaluated.The CCC values were dependent on the concentration of PFOA,however a pronounced effect of SDS concentration on the CCC values was not observed.The CCC values of the MWCNTs were 51.6 mmol/L in NaCl and 0.28 mmol/L in CaCl 2 solutions,which suggested pronounced differences in the effects of Na+ and Ca2+ ions on the aggregation of the MWCNTs.The presence of both PFOA and SDS significantly decreased the CCC values of the MWCNTs in NaCl solution.The aggregation of the MWCNTs took place under acidic conditions and was not notably altered under neutral and alkaline conditions due to the electrostatic repulsion of deprotonated functional groups on the surface of the MWCNTs.  相似文献   
7.
This study quantifies and spatially characterizes land use and land cover changes in the Segara Anakan lagoon (SAL), Java, Indonesia, from 1987–2006. Classification of four satellite (SPOT) images from the years 1987, 1995, 2004 and 2006 and field ground truth data from 2004 and 2005 were used for map generation. The results show major changes in the western area of the SAL, with large area increases of rice fields, dry land agriculture, aquaculture and rural areas, and decreases in mangrove cover, mud flat and lagoon area. In the eastern area, minor decreases in mangrove area and increase in aquaculture, rural and industrial areas were also observed. Changes are due to the filling of the lagoon with riverine sediments derived from the hinterland and to mangrove conversion and resources exploitation. The results of this study provide basic information which is required for developing measures towards a sustainable management and conservation of the SAL.  相似文献   
8.
9.
Abstract: Although economic analysis can be used to argue for preservation of species and habitats, many natural assets represent inferior investments in society's asset portfolio. We demonstrate this for the case of ancient temperate rainforests and minke whales (  Balaenoptera acutorostrata ). For both rainforests and whales, we determined their value for harvest and balanced this against society's valuation of the preserved stock. For the market and nonmarket data available, we then determined how much rainforest and how many minke whales global society should keep in its asset portfolio. Although ecologists increasingly attempt to justify preservation of biological assets on economic grounds, we argue that this might be a dangerous approach to take. Ultimately, it may be necessary to reexamine the ethical foundations for conservation of nature and biodiversity, including the economist's use of utilitarianism. We suggest that the safe minimum standard approach may prove useful in practice.  相似文献   
10.
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