全文获取类型
收费全文 | 472篇 |
免费 | 2篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 5篇 |
环保管理 | 29篇 |
综合类 | 166篇 |
基础理论 | 145篇 |
污染及防治 | 112篇 |
评价与监测 | 12篇 |
社会与环境 | 15篇 |
出版年
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 23篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 15篇 |
2008年 | 20篇 |
2007年 | 24篇 |
2006年 | 32篇 |
2005年 | 21篇 |
2004年 | 9篇 |
2003年 | 16篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 19篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1991年 | 4篇 |
1989年 | 6篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1983年 | 6篇 |
1969年 | 3篇 |
1967年 | 2篇 |
1966年 | 7篇 |
1965年 | 4篇 |
1964年 | 8篇 |
1963年 | 7篇 |
1962年 | 2篇 |
1961年 | 5篇 |
1960年 | 6篇 |
1959年 | 3篇 |
1958年 | 3篇 |
1957年 | 6篇 |
1956年 | 3篇 |
1955年 | 5篇 |
1954年 | 4篇 |
1953年 | 7篇 |
1951年 | 2篇 |
1950年 | 2篇 |
1938年 | 2篇 |
1934年 | 2篇 |
排序方式: 共有492条查询结果,搜索用时 779 毫秒
1.
Jürgen Breitung Dirk Bruns-Nagel Eberhard von Löw Klaus Steinbach Lothar Kaminski Rainer Haas Diethard Gemsa 《Environmental Sciences Europe》1995,7(4):195-200
Within the limits of a feasability study abouton-site bioremediation methods for TNT-contaminated soils, composting was chosen as a very promising and cheap method. This method was critically compared with those described in the literature and was primarily rated under ecotoxicological aspects. The investigated location is the former munition plant «Tanne» in the aerea of Clausthal-Zellerfeld in Lower Saxony, Germany. To estimate the autochtonic microflora, we assessed the number of aerobic heterotrophic bacteria and determined their respiration activity in soils. In addition, we isolated bacteria and examined their capacity to metabolize TNTin vitro. Both the amount of autochtonic microrganisms (4.7×108 to 1.2×1010 colony forming units (cfu)/kg dryweight) as well as their respiration activity did not correlate with the concentrations of nitrotoluenes in the soils. With high contaminated soil (20 g TNT/kg dry weight) we carried out a small compost in the range of 10 liters. During 28 days of composting TNT-concentration decrease over 90% and only minor amounts of monoaminodinitrotoluenes were generated. However, an acidic pretreatment of the compost material at the end of the reaction showed that TNT could be partially resolved under these extreme conditions and that an ecotoxicological risk may still exist. Possible changes in the realization of the composting process in order to make sure that the contaminants are savely bound to the humin matrix are discussed. 相似文献
2.
3.
4.
5.
Supportive Breeding and Variance Effective Population Size 总被引:2,自引:0,他引:2
The practice of supporting weak, wild populations through release of individuals bred in captivity is becoming an increasingly important conservation measure. A frequently recommended form of such breeding-release activity refers to supportive breeding: a fraction of the target population is brought into captivity for reproduction, and the resulting progeny are released to mix with the wild segment of the population. We derived an expression for the variance effective size of a population managed through supportive breeding and discuss its relationship to previously published equations that are based on the assumption of random mating. We show that the effect of supportive breeding may be quite different on the inbreeding and the variance effective sizes. Whereas supportive breeding always results in a reduction of the inbreeding effective number, the variance effective number may either decrease, increase, or remain unchanged. We discuss these observations in relation to conservation management and suggest some general guidelines for supportive breeding situations. Our recommendations include making a distinction between inbreeding and variance effective numbers; taking particular care when dealing with organisms with high reproductive potential; assuring that the amount of drift be no larger than it would be without supportive breeding; and focusing primarily on the variance effective size of a population-that is, on the effective number directly related to the rate of loss of gene diversity. 相似文献
6.
7.
Klaus Strobach 《Die Naturwissenschaften》1980,67(7):321-331
Alfred Wegener's most important work, the theory of continental drift, has a key position in the history of geophysics and has crucially advanced the discussion of this central problem of geodynamics amongst supporters and adversaries. The aim of this paper is to paint a portrait of Wegener's personality, of his stations of life, and of his interests and research work. The conceptions of the origin of continents and oceans prior to Wegener, and the further development of his ideas after his death on the ice cup of Greenland 50 years ago are discussed. 相似文献
8.
9.
10.