全文获取类型
收费全文 | 6187篇 |
免费 | 725篇 |
国内免费 | 1194篇 |
出版年
2024年 | 20篇 |
2023年 | 94篇 |
2022年 | 209篇 |
2021年 | 349篇 |
2020年 | 275篇 |
2019年 | 345篇 |
2018年 | 265篇 |
2017年 | 258篇 |
2016年 | 340篇 |
2015年 | 448篇 |
2014年 | 534篇 |
2013年 | 543篇 |
2012年 | 683篇 |
2011年 | 638篇 |
2010年 | 411篇 |
2009年 | 377篇 |
2008年 | 403篇 |
2007年 | 319篇 |
2006年 | 308篇 |
2005年 | 240篇 |
2004年 | 240篇 |
2003年 | 212篇 |
2002年 | 174篇 |
2001年 | 86篇 |
2000年 | 75篇 |
1999年 | 63篇 |
1998年 | 41篇 |
1997年 | 25篇 |
1996年 | 30篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 9篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1950年 | 2篇 |
排序方式: 共有8106条查询结果,搜索用时 15 毫秒
1.
To clarify the mechanisms of Nosema ceranae parasitism, we deep-sequenced both honey bee host and parasite mRNAs throughout a complete 6-day infection cycle. By time-series analysis, 1122 parasite genes were significantly differently expressed during the reproduction cycle, clustering into 4 expression patterns. We found reactive mitochondrial oxygen species modulator 1 of the host to be significantly down regulated during the entire infection period. Our data support the hypothesis that apoptosis of honey bee cells was suppressed during infection. We further analyzed genome-wide genetic diversity of this parasite by comparing samples collected from the same site in 2007 and 2013. The number of SNP positions per gene and the proportion of non-synonymous substitutions per gene were significantly reduced over this time period, suggesting purifying selection on the parasite genome and supporting the hypothesis that a subset of N. ceranae strains might be dominating infection. 相似文献
2.
3.
4.
5.
6.
7.
Oat leaf base: tissue with an efficient regeneration capacity 总被引:1,自引:1,他引:0
Summary An efficient short term regeneration system using seedling derived oat (Avena sativa) leaf tissue has been developed. Callus derived from the leaf base showed a higher response of plant regeneration than callus initiated from mesocotyls and more mature parts of the leaves. A correlation between the nuclear DNA content of the donor material, as analysed with flow cytometry, and its ability to form callus was observed. Somatic embryogenesis was histologically recognised from callus derived from tissue close to the apical meristem. Plant regeneration media with various concentrations of auxin were tested. Callus from three different cultivars had a similar regeneration potential with an optimal regeneration frequency of 60%. About 2 months after inoculation regenerated plantlets could be moved to a greenhouse for cultivation.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- DAPI
6-diamidino-2-phenylindole
- IAA
indole-3-acetic acid
- KT
kinetin
- MS
Murashige and Skoog's medium
- NAA
naphthalene acetic acid 相似文献
8.
9.
10.