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   383篇
  免费   1篇
  国内免费   1篇
安全科学   1篇
废物处理   9篇
环保管理   11篇
综合类   222篇
基础理论   36篇
污染及防治   68篇
评价与监测   29篇
社会与环境   9篇
  2017年   5篇
  2016年   5篇
  2014年   6篇
  2013年   15篇
  2012年   6篇
  2011年   8篇
  2010年   6篇
  2009年   4篇
  2008年   21篇
  2007年   12篇
  2006年   6篇
  2005年   5篇
  2004年   11篇
  2003年   9篇
  2002年   7篇
  1997年   4篇
  1994年   6篇
  1993年   4篇
  1992年   5篇
  1991年   5篇
  1990年   6篇
  1989年   6篇
  1988年   8篇
  1987年   6篇
  1985年   5篇
  1984年   4篇
  1979年   5篇
  1978年   7篇
  1977年   4篇
  1976年   6篇
  1969年   3篇
  1968年   9篇
  1967年   8篇
  1966年   5篇
  1965年   6篇
  1964年   6篇
  1963年   5篇
  1961年   5篇
  1958年   3篇
  1957年   3篇
  1956年   5篇
  1954年   6篇
  1952年   4篇
  1943年   5篇
  1934年   3篇
  1924年   4篇
  1919年   3篇
  1918年   4篇
  1917年   4篇
  1913年   4篇
排序方式: 共有385条查询结果,搜索用时 15 毫秒
111.
112.
Besprechungen     
Sackur  O.  Posener  Th.  Scheffer  W.  Friederichsen  Max  Lachmann  R.  Feige  E.  Schmidt  E. W.  Tobler  F.  Heinze  B.  Bruck  Carl 《Die Naturwissenschaften》1913,1(29):697-703
The Science of Nature -  相似文献   
113.
114.
115.
There is a growing assumption that payments for environmental services including carbon sequestration and greenhouse gas emission reduction provide an opportunity for poverty reduction and the enhancement of sustainable development within integrated natural resource management approaches. Yet in experiential terms, community-based natural resource management implementation falls short of expectations in many cases. In this paper, we investigate the asymmetry between community capacity and the Land Use Land Use Change Forestry (LULUCF) provisions of the Clean Development Mechanism within community forests in Cameroon. We use relevant aspects of the Clean Development Mechanism criteria and notions of “community capacity” to elucidate determinants of community capacity needed for CDM implementation within community forests. The main requirements are for community capacity to handle issues of additionality, acceptability, externalities, certification, and community organisation. These community capacity requirements are further used to interpret empirically derived insights on two community forestry cases in Cameroon. While local variations were observed for capacity requirements in each case, community capacity was generally found to be insufficient for meaningful uptake and implementation of Clean Development Mechanism projects. Implications for understanding factors that could inhibit or enhance community capacity for project development are discussed. We also include recommendations for the wider Clean Development Mechanism/Kyoto capacity building framework.  相似文献   
116.
W?hrend eines Studien- und Beratungs-aufenthalts des Autors bei der Saudi-Arabischen Umweltbeh?rde im Juni/Juli 1991 wurde der Zustand der Saudi-Arabischen Golfküste untersucht. Von der Kuwaitischen Grenze bis zur Insel Abu Ali sind ca. 770 km Küste lückenlos zwischen Hoch- und Niedrigwasserlinie ver?lt. W?hrend an den energiereicheren Au?enküsten eine biologische Regeneration erwartet werden kann, ist sie in den energiearmen Buchten nicht ohne technische Ma?nahmen denkbar. Ver?lungen gibt es au?erdem am Meeresgrund in noch unbekanntem Ausma?. Für die Ma?nahmen wird die Notwendigkeit betont, ein Umweltqualit?tsziel festzulegen, das in der Entwicklung zu einem Naturreservat bestehen sollte.  相似文献   
117.
118.
The Holt-Oram syndrome is an autosomal dominant disorder consisting of a congenital heart defect in combination with characteristic upper limb abnormalities. This report presents the ultrasonographic follow-up of two fetuses at risk for the Holt-Oram syndrome. In the first fetus, the existence of Holt-Oram syndrome was suspected at 22 weeks of gestation; a ventricular septal defect, an atrial septal defect, and a minor skeletal defect were found. In the second fetus, no structural abnormalities were discovered until the 30th week, when a small atrial septal defect was detected. In both pregnancies, it was possible to exclude early in gestation the more severe forms of the Holt-Oram syndrome.  相似文献   
119.
The behavioral and electroantennographic responses of Cydia pomonella (L.) to the ripe pear volatile ethyl (2E,4Z)-2,4-decadienoate (Et-E,Z-DD), were compared in insecticide-susceptible and -resistant populations originating from southern France. A dose–response relationship to this kairomonal attractant was established for antennal activity and did not reveal differences between susceptible and resistant strains. Conversely, males of the laboratory strains expressing metabolic [cytochrome P450-dependent mixed-function oxidases (mfo)] or physiological (kdr-type mutation of the sodium-channel gene) resistance mechanisms exhibited a significantly higher response to Et-E,Z-DD than those of the susceptible strain in a wind tunnel experiment. No response of the females to this kairomone could be obtained in our wind-tunnel conditions. In apple orchards, mfo-resistant male moths were captured at significantly higher rates in kairomone-baited traps than in traps baited with the sex pheromone of C. pomonella. Such a differential phenomenon was not verified for the kdr-resistant insects, which exhibited a similar response to both the sex pheromone and the kairomonal attractant in apple orchards. Considering the widespread distribution of metabolic resistance in European populations of C. pomonella and the enhanced behavioral response to Et-E,Z-DD in resistant moths, the development of control measures based on this kairomonal compound would be of great interest for the management of insecticide resistance in this species.  相似文献   
120.
Biodegradation tests with bacteria from activated sludge revealed the probable persistence of cyano-based ionic liquid anions when these leave waste water treatment plants. A possible biological treatment using bacteria capable of biodegrading similar compounds, namely cyanide and cyano-complexes, was therefore examined. With these bacteria from the genera Cupriavidus, the ionic liquid anions B(CN)4 ?, C(CN)3 ?, N(CN)2 ? combined with alkaline cations were tested in different growth media using ion chromatography for the examination of their primary biodegradability. However, no enhanced biodegradability of the tested cyano-based ionic liquids was observed. Therefore, an in vitro enzymatic hydrolysis test was additionally run showing that all tested ionic liquid (IL) anions can be hydrolysed to their corresponding amides by nitrile hydratase, but not by nitrilase under the experimental conditions. The biological stability of the cyano-based anions is an advantage in technological application, but the occurrence of enzymes that are able to hydrolyse the parent compound gives a new perspective on future cyano-based IL anion treatment.  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