全文获取类型
收费全文 | 219篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
废物处理 | 6篇 |
环保管理 | 13篇 |
综合类 | 143篇 |
基础理论 | 32篇 |
污染及防治 | 18篇 |
评价与监测 | 3篇 |
社会与环境 | 6篇 |
出版年
2023年 | 4篇 |
2021年 | 3篇 |
2015年 | 2篇 |
2013年 | 10篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1992年 | 2篇 |
1978年 | 2篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1965年 | 4篇 |
1964年 | 3篇 |
1963年 | 5篇 |
1962年 | 4篇 |
1959年 | 6篇 |
1957年 | 2篇 |
1956年 | 4篇 |
1955年 | 7篇 |
1954年 | 5篇 |
1951年 | 6篇 |
1950年 | 5篇 |
1949年 | 2篇 |
1947年 | 2篇 |
1946年 | 3篇 |
1941年 | 5篇 |
1940年 | 6篇 |
1939年 | 5篇 |
1938年 | 2篇 |
1937年 | 7篇 |
1934年 | 2篇 |
1932年 | 4篇 |
1930年 | 2篇 |
1929年 | 2篇 |
1923年 | 2篇 |
1920年 | 4篇 |
1918年 | 2篇 |
1913年 | 2篇 |
排序方式: 共有221条查询结果,搜索用时 15 毫秒
191.
Summary. The cabbage root fly possesses highly specialised and extremely sensitive receptors for “CIF”, a group of compounds present
on cabbage leaves in very small amounts, and the strongest oviposition stimulants known. Here we present evidence that the
same receptors are sensitive to a methanol extract of cabbage root fly eggs, which may contain the fly's host marking pheromone.
Based on these results, the possible role of CIF in cabbage root fly behaviour and in cabbage plants is discussed.
Received 4 April 2001; accepted 24 September 2001. 相似文献
192.
Germany seems to be one of the leading nations in solid waste management, especially in the case of packaging waste; success
stories about the ongoing increase in recycling strengthen this impression. However, enormous costs and questionable ecological
benefits are the result of Germany's packaging ordinance and the formation of the recycling organization Duales System Deutschland
(DSD). This article shows that similar progress in the reduction and recycling of packaging could have been realized without
the packaging ordinance and dual system, with lower costs. This regulatory impact analysis of the German packaging ordinance
covers all the effects on the different life-cycle stages of packaging, from production to recycling or disposal. The conclusion
is that a fragmentary solid waste management approach – one that is based, like the German packaging ordinance, more on ideology
than on facts – leads to enormous costs and questionable ecological benefits. To improve this situation, there is a need for
an integrated solid waste management approach, based on evaluation of the economic, environmental, and social effects of different
waste management options for the materials involved.
Received: February 4, 1999 / Accepted: April 30, 1999 相似文献
193.
Brominated flame retardants (BFRs) are widely used in plastics, textile coatings, electrical appliances and printed circuit boards to prohibit the development of fires. In order to investigate how exposure to BFRs is related to specific occupations, samples were obtained from Norwegian individuals working at an electronics dismantling facility, in the production of printed circuit boards, or as laboratory personnel. Nine BFRs were quantified in the plasma samples: 2,4,4'-tribromodiphenyl ether (BDE-28), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), 2,2',4,4',6-pentabromodiphenyl ether (BDE-100), 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153), 2,2',4,4',5,6'-hexabromodiphenyl ether (BDE-154), 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE-183), 2,4,6-tribromophenol (TriBP) and tetrabromobisphenol A (TBBP-A). The BFRs were extracted from plasma using solid-phase extraction (SPE). The plasma lipids were decomposed by treatment with concentrated sulfuric acid directly on the SPE column, prior to the elution of the BFRs. Following diazomethane derivatization, the samples were analysed by gas chromatography-electron capture mass spectrometry. The subjects working at the electronics dismantling plant had significantly higher plasma levels of TBBP-A and BDE-153 compared to the other groups, and the heptabrominated congener BDE-183 was only detected in plasma from this group. TriBP was generally the most abundant BFR present, and the plasma concentrations were in the range 0.17-81 ng g-1 lipids. BDE-47 was the dominant BDE congener in all the individual samples and the levels were in the range 0.43-14.6 ng g-1 lipids. The total amounts of the seven BDEs were 8.8, 3.9 and 3.0 ng g-1 lipids for the group of electronics dismantlers, circuit board producers and laboratory personnel, respectively. Generally, large variations in the individual concentration levels were found within the groups, especially in the group of electronics dismantlers, where the relative standard deviations for BDE concentrations were in the range 23-164%. The levels of BFRs were not correlated to age or the level of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153). The present work indicates that the population in Norway is exposed to several BFRs, probably with food as a major source. The elevated level of higher brominated BDEs and TBBP-A in the plasma from the workers at the dismantling plant suggests an additional occupational exposure for these individuals. Thus, human exposure to BFRs seems to originate from a combination of different sources; however, further studies investigating plasma samples from a larger number of individuals are necessary for a more complete assessment of human exposure pathways to these environmental contaminants. 相似文献
194.
A. Brückner Erich Becher R. O. Neumann V. Jollos U. Friedemann 《Die Naturwissenschaften》1923,11(10):180-183
195.
196.
197.
198.
The Science of Nature - 相似文献
199.
200.
Erich v. Drygalski A. Heintz G. Melchers W. Schnakenbeck 《Die Naturwissenschaften》1938,26(15):236-238