全文获取类型
收费全文 | 14736篇 |
免费 | 3539篇 |
国内免费 | 6篇 |
出版年
2017年 | 152篇 |
2016年 | 272篇 |
2015年 | 586篇 |
2014年 | 684篇 |
2013年 | 919篇 |
2012年 | 503篇 |
2011年 | 331篇 |
2010年 | 487篇 |
2009年 | 569篇 |
2008年 | 345篇 |
2007年 | 323篇 |
2006年 | 399篇 |
2005年 | 300篇 |
2004年 | 266篇 |
2003年 | 270篇 |
2002年 | 298篇 |
2001年 | 226篇 |
2000年 | 179篇 |
1999年 | 247篇 |
1998年 | 375篇 |
1997年 | 291篇 |
1996年 | 354篇 |
1995年 | 316篇 |
1994年 | 323篇 |
1993年 | 335篇 |
1992年 | 320篇 |
1991年 | 320篇 |
1990年 | 325篇 |
1989年 | 303篇 |
1988年 | 341篇 |
1987年 | 313篇 |
1986年 | 308篇 |
1985年 | 311篇 |
1984年 | 291篇 |
1983年 | 289篇 |
1982年 | 272篇 |
1981年 | 271篇 |
1980年 | 302篇 |
1979年 | 276篇 |
1978年 | 274篇 |
1977年 | 255篇 |
1976年 | 223篇 |
1975年 | 238篇 |
1974年 | 210篇 |
1973年 | 216篇 |
1972年 | 159篇 |
1971年 | 177篇 |
1970年 | 186篇 |
1969年 | 174篇 |
1968年 | 177篇 |
排序方式: 共有10000条查询结果,搜索用时 890 毫秒
1.
HIF-1 expression in healing wounds: HIF-1alpha induction in primary inflammatory cells by TNF-alpha 总被引:12,自引:0,他引:12
2.
3.
A statistical method for correlating tRNA sequence with amino acid specificity. 总被引:3,自引:1,他引:2 下载免费PDF全文
A statistical method for finding the nucleotide positions in tRNA sequences that correlate with amino acid specificity has been developed. The procedure involves finding the subset of nucleotide positions and groups of positions where the marginal density of one amino acid tRNA class does not overlap that of any other amino acid class. The procedure is an application of a statistical method known as the Expectation Maximization algorithm. 相似文献
4.
5.
6.
7.
8.
9.
10.
Ivonne J. Garzn‐Ordua Shaun L. Winterton Yunlan Jiang Laura C.V. Breitkreuz Peter Duelli Michael S. Engel Norman D. Penny Catherine A. Tauber Atsushi Mochizuki Xingyue Liu 《Systematic Entomology》2019,44(3):499-513
We present a time‐calibrated phylogeny of the charismatic green lacewings (Neuroptera: Chrysopidae). Previous phylogenetic studies on the family using DNA sequences have suffered from sparse taxon sampling and/or limited amounts of data. Here we combine all available previously published DNA sequence data and add to it new DNA sequences generated for this study. We analysed these data in a supermatrix using Bayesian and maximum likelihood methods and provide a phylogenetic hypothesis for the family that recovers strong support for the monophyly of all subfamilies and resolves relationships among a large proportion of chrysopine genera. Chrysopinae tribes Leucochrysini and Belonopterygini were recovered as monophyletic sister clades, while the species‐rich tribe Chrysopini was rendered paraphyletic by Ankylopterygini. Relationships among the subfamilies were resolved, although with relatively low statistical support, and the topology varied based on the method of analysis. Greatest support was found for Apochrysinae as sister to Nothochrysinae and Chrysopinae, which is in contrast to traditional concepts that place Nothochrysinae as sister to the rest of the family. Divergence estimates suggest that the stem groups to the various subfamilies diverged during the Triassic‐Jurassic, and that stem groups of the chrysopine tribes diverged during the Cretaceous. 相似文献