全文获取类型
收费全文 | 11333篇 |
免费 | 79篇 |
国内免费 | 83篇 |
专业分类
安全科学 | 283篇 |
废物处理 | 500篇 |
环保管理 | 1432篇 |
综合类 | 2462篇 |
基础理论 | 2556篇 |
环境理论 | 5篇 |
污染及防治 | 2955篇 |
评价与监测 | 684篇 |
社会与环境 | 563篇 |
灾害及防治 | 55篇 |
出版年
2022年 | 91篇 |
2021年 | 97篇 |
2019年 | 69篇 |
2018年 | 151篇 |
2017年 | 131篇 |
2016年 | 223篇 |
2015年 | 172篇 |
2014年 | 243篇 |
2013年 | 820篇 |
2012年 | 307篇 |
2011年 | 427篇 |
2010年 | 337篇 |
2009年 | 395篇 |
2008年 | 428篇 |
2007年 | 491篇 |
2006年 | 431篇 |
2005年 | 352篇 |
2004年 | 367篇 |
2003年 | 373篇 |
2002年 | 332篇 |
2001年 | 428篇 |
2000年 | 312篇 |
1999年 | 205篇 |
1998年 | 115篇 |
1997年 | 123篇 |
1996年 | 108篇 |
1995年 | 154篇 |
1994年 | 148篇 |
1993年 | 123篇 |
1992年 | 130篇 |
1991年 | 149篇 |
1990年 | 119篇 |
1989年 | 127篇 |
1988年 | 132篇 |
1987年 | 114篇 |
1986年 | 83篇 |
1985年 | 99篇 |
1984年 | 124篇 |
1983年 | 125篇 |
1982年 | 123篇 |
1981年 | 97篇 |
1980年 | 93篇 |
1979年 | 106篇 |
1978年 | 89篇 |
1977年 | 84篇 |
1976年 | 78篇 |
1975年 | 90篇 |
1974年 | 101篇 |
1972年 | 69篇 |
1965年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Data are presented on the mutagenicity of an organic extract of a composite sample of urban air particulates and of thirty PAH compounds in such samples, including four quinone derivatives, isolated quantitatively by thin-layer chromatography and identified by fluorescence or other spectral techniques. Mutagenic activity was determined by the Ames assay, using histidine auxotrophs of Salmonella typhimurium strains TA98, TA100, TA1537 and TA1538. All compounds were dissolved in dimethyl sulfoxide (DMSO) which was the least toxic of eight organic solvents tested.The mutagenic activity of a benzene extract of suspended particulates from the air of Hamilton, Ontario was significantly greater with strain TA98 than with strain TA100, suggesting the presence of more frame-shift acting mutagens. The mutagenic response of this extract was similar with and without S-9 activation.Mutagenic tests on the 30 PAH compounds indicated that only the benzo(a)pyrene quinones were direct acting mutagens. All of the chemical compounds were tested with and without S-9 activation. The following PAH showed unequivocal mutagenic activity, with S-9 activation: benz(a)anthracene, benzo-(a)pyrene, benzo(ghi)perylene, benzo(rst)pentaphene, benzophenanthrene, chrysene, 1, 2, 3, 4-dibenzanthracene, 2, 3, 6, 7-dibenzanthracene, and 3-methyl cholanthrene. The quinones of 1, 6-; 3, 6-; and 6, 12-benzo(a)pyrenes showed weak mutagenic activity but 3, 6-benzo(a)pyrene elicited also a photodynamic response. 相似文献
95.
96.
97.
98.
99.
100.
Irwin F Lipnowski 《Journal of Environmental Economics and Management》1976,3(3):205-214
A well-established criterion for determining the growth potential of an economy, the technology of which can be represented by a nonnegative indecomposable square matrix, is examined critically. The concept of growth upon which this criterion is established is shown to be ambiguous since the environmental repercussions of economic activity are completely ignored. Assuming that this economy possesses an antipollution technology which has hitherto been ignored, an alternative criterion to gauge growth potential in the presence of complete environmental preservation is proposed. The magnitude of the uniform rate of profit which must obtain when the economy ignores the environment if a policy of environmental preservation is to be deemed technically feasible is calculated. Finally, a number of factors which would facilitate the implementation of a policy of environmental preservation are discussed. 相似文献