全文获取类型
收费全文 | 92篇 |
免费 | 2篇 |
专业分类
安全科学 | 1篇 |
环保管理 | 3篇 |
综合类 | 57篇 |
基础理论 | 16篇 |
污染及防治 | 15篇 |
社会与环境 | 1篇 |
灾害及防治 | 1篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 3篇 |
1970年 | 3篇 |
1965年 | 2篇 |
1964年 | 5篇 |
1963年 | 5篇 |
1962年 | 4篇 |
1961年 | 5篇 |
1960年 | 1篇 |
1957年 | 1篇 |
1955年 | 2篇 |
1954年 | 3篇 |
1951年 | 1篇 |
1950年 | 1篇 |
1943年 | 1篇 |
1932年 | 1篇 |
1931年 | 1篇 |
1930年 | 1篇 |
1921年 | 1篇 |
排序方式: 共有94条查询结果,搜索用时 31 毫秒
21.
22.
Atrazine induction of a family 4 cytochrome P450 gene in Chironomus tentans (Diptera: Chironomidae) 总被引:1,自引:0,他引:1
Cytochrome P450-dependent microsomal monooxygenase (P450) activity was measured in control and atrazine-exposed third instar midge larvae, Chironomus tentans. Significantly elevated O-demethylase activity was observed in gut homogenates taken from midges exposed to atrazine concentrations from 1 to 10 ppm for 90 h. No significant induction was observed at atrazine concentrations below 1 ppm. A region of a cytochrome P450 family 4 gene was amplified and sequenced from C. tentans larvae. Alignments of inferred amino acid sequences with other insect CYP4 gene homologues indicate a high degree of similarity. Northern blot analysis employing the CYP4 gene fragment as a probe showed an over-expression in C. tentans exposed to atrazine. The results support the previously identified inducibility of cytochrome P450-dependent activity and provide insight into the potential consequences of atrazine exposure to aquatic organisms. 相似文献
23.
24.
Two simplified versions of a numerical life cycle model for diazotrophic cyanobacteria (of the order Nostocales) are developed and evaluated. Both consider two-life cycle stages, one growing, nitrogen-fixing stage and one stage that combines the resting, germinating and vegetative stages. The versions differ in the vertical resolution of the non-diazotrophic stage: version 1 collects the biomass in one layer at the bottom, version 2 considers sinking and rising of biomass explicitly. The results of the two versions are compared with a complex cyanobacteria life cycle model which describes four different life cycle stages each with two internal quotas for energy and nitrogen. The two simplified approaches show a good agreement with respect to the main characteristics of cyanobacteria dynamics (timing and duration of blooms, magnitude of nitrogen fixation, interannual variability). Our model study shows that both simplified approaches are suitable to be implemented into three-dimensional coastal or lake models. 相似文献
25.
26.
27.
28.
29.
30.