全文获取类型
收费全文 | 660篇 |
免费 | 53篇 |
专业分类
713篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 15篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 21篇 |
2015年 | 29篇 |
2014年 | 37篇 |
2013年 | 50篇 |
2012年 | 47篇 |
2011年 | 38篇 |
2010年 | 30篇 |
2009年 | 29篇 |
2008年 | 39篇 |
2007年 | 43篇 |
2006年 | 46篇 |
2005年 | 36篇 |
2004年 | 32篇 |
2003年 | 36篇 |
2002年 | 27篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有713条查询结果,搜索用时 0 毫秒
711.
712.
Srinivasan Bharathkumar N. RameshKumar Diby Paul V. R. Prabavathy Sudha Nair 《World journal of microbiology & biotechnology》2008,24(3):387-394
Variations in chemical parameters and bacterial populations in mangrove rhizosphere samples were noted for different sites.
The C, N, P and K contents as well as pH, EC and salinity showed variation between sites. Significant differences in soil
properties were also found in sampling sites. Two types of soil were noted among sites. Guesthouse had significantly higher
organic matter and nutrient content (N) than other three sites suggesting that human discharges, litter deposition and surface
runoff were major nutrient inputs. This contaminated site was located at the landward edges. Positive correlations between
organic matter, N, P and K contents were found suggesting that these nutrients were from similar input sources. Effects of
sampling sites on microbial diversity were also analyzed via SSCP. Porteresia coarctata and Rhizophora mucronata did not show any variation in the banding patterns among replicates sampled in short distance within site. But Sonneratia apetala showed variation among replicates sampled in distance within site. A significant variation was noted in the SSCP profile
among replicates between sites. The majority of dominant SSCP band sequences were related to bacterial genera of root and
root-free soil environments, namely Bacillus, Planococcus, Planomicrobium, low G+C Gram-positive bacterium, glacial ice bacterium and unidentified bacteria. In the analysis of 16S rRNA sequences,
members belonging to the phylum Firmicutes dominated the sequence collection. The phylogenetic analysis of 16S rRNA gene sequences showed close relationships to a wide range of clones or bacterial species of phylum Firmicutes and unidentified bacteria. 相似文献
713.
Thebgl operon ofEscherichia coli, which encodes the genes necessary for transport and catabolism of β-glucosides, is silent in wild-type cells and is activated
by the transposition of IS elements. The silent form of the operon appears to be the stable state. We isolated Bgl- revertants of an activated strain after growth under nonselective conditions to understand whether activation of the cryptic
operon by IS elements is reversible. Genetic and molecular analyses revealed that a majority of revertants carry deletions
of thebgl structural genes, indicating that an irreversible alteration has occurred in the operon. Implications of these results for
the evolution and maintenance of cryptic genes are discussed. [Yakkundi A., Moorthy S. and Mahadevan S. 1998 Reversion of
anE. coli strain carrying an IS1-activatedbgl operon under nonselective conditions is predominantly due to deletions within the structural genes.J. Genet.
77, 21–26] 相似文献