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   73篇
  免费   0篇
系统科学   1篇
理论与方法论   1篇
现状及发展   26篇
研究方法   3篇
综合类   41篇
自然研究   1篇
  2018年   1篇
  2015年   1篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2008年   5篇
  2007年   5篇
  2006年   6篇
  2005年   3篇
  2004年   1篇
  2003年   2篇
  2002年   3篇
  2001年   4篇
  2000年   3篇
  1999年   1篇
  1997年   2篇
  1995年   1篇
  1994年   1篇
  1987年   1篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1978年   1篇
  1977年   4篇
  1976年   2篇
  1973年   2篇
  1970年   2篇
  1968年   2篇
  1965年   1篇
  1958年   2篇
排序方式: 共有73条查询结果,搜索用时 0 毫秒
71.
Summary Three different tests on houseflies (Musca domestica L.) revealed that both pheromone-free pseudoflies and male partner flies exhibit in the presence of mixtures of long-chain (Z)-9-alkenes or pure (Z)-9-tricosene enhanced releasing effects for two optical cues, which stimulate male houseflies to mating strikes and houseflies of both sexes to aggregation.  相似文献   
72.
Summary The participation of highly energetic oxygen species in the ATP-induced bioluminescence of a firefly-extract has been investigated. The inhibition of light emission by a variety of specific scavengers suggests that singlet oxygen, superoxide radicals and hydroxyl radicals are important intermediates in the firefly bioluminescence reaction.Acknowledgments. I thank Prof. R. Bachofen, Institut für Allgemeine Botanik, Abteilung Mikrobiologie, Universität Zürich, Switzerland, in whose laboratory most of these studies have been performed, for his cooperativity. Financial support by the Deutsche Studienstiftung is gratefully acknowledged.  相似文献   
73.
Increase in tropospheric nitrogen dioxide over China observed from space   总被引:15,自引:0,他引:15  
Richter A  Burrows JP  Nüss H  Granier C  Niemeier U 《Nature》2005,437(7055):129-132
Emissions from fossil fuel combustion and biomass burning reduce local air quality and affect global tropospheric chemistry. Nitrogen oxides are emitted by all combustion processes and play a key part in the photochemically induced catalytic production of ozone, which results in summer smog and has increased levels of tropospheric ozone globally. Release of nitrogen oxide also results in nitric acid deposition, and--at least locally--increases radiative forcing effects due to the absorption of downward propagating visible light. Nitrogen oxide concentrations in many industrialized countries are expected to decrease, but rapid economic development has the potential to increase significantly the emissions of nitrogen oxides in parts of Asia. Here we present the tropospheric column amounts of nitrogen dioxide retrieved from two satellite instruments GOME and SCIAMACHY over the years 1996-2004. We find substantial reductions in nitrogen dioxide concentrations over some areas of Europe and the USA, but a highly significant increase of about 50 per cent-with an accelerating trend in annual growth rate-over the industrial areas of China, more than recent bottom-up inventories suggest.  相似文献   
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