全文获取类型
收费全文 | 15849篇 |
免费 | 1356篇 |
国内免费 | 11篇 |
专业分类
17216篇 |
出版年
2023年 | 74篇 |
2022年 | 132篇 |
2021年 | 280篇 |
2020年 | 138篇 |
2019年 | 182篇 |
2018年 | 250篇 |
2017年 | 188篇 |
2016年 | 329篇 |
2015年 | 572篇 |
2014年 | 690篇 |
2013年 | 927篇 |
2012年 | 1051篇 |
2011年 | 1056篇 |
2010年 | 666篇 |
2009年 | 578篇 |
2008年 | 901篇 |
2007年 | 917篇 |
2006年 | 829篇 |
2005年 | 824篇 |
2004年 | 826篇 |
2003年 | 753篇 |
2002年 | 674篇 |
2001年 | 237篇 |
2000年 | 204篇 |
1999年 | 237篇 |
1998年 | 224篇 |
1997年 | 162篇 |
1996年 | 144篇 |
1995年 | 134篇 |
1994年 | 153篇 |
1993年 | 152篇 |
1992年 | 190篇 |
1991年 | 148篇 |
1990年 | 141篇 |
1989年 | 138篇 |
1988年 | 132篇 |
1987年 | 106篇 |
1986年 | 107篇 |
1985年 | 119篇 |
1984年 | 114篇 |
1983年 | 81篇 |
1982年 | 87篇 |
1981年 | 77篇 |
1980年 | 96篇 |
1979年 | 101篇 |
1978年 | 77篇 |
1977年 | 82篇 |
1976年 | 74篇 |
1974年 | 57篇 |
1973年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Effect of carbon source on lysine-mediated inhibition of postexponential growth of Saccharomyces cerevisiae 总被引:1,自引:0,他引:1 下载免费PDF全文
T G Watson 《Journal of bacteriology》1983,154(2):1013-1014
Lysine-mediated inhibition of postexponential growth in Saccharomyces cerevisiae occurred when glucose, fructose, or maltose, but not lactate, pyruvate, or ethanol, was used as the carbon source. Arginine starvation is not responsible for the inhibitory effect, since neither the intracellular pool of glucose-grown (inhibited) cells nor that of lactate-grown (noninhibited) cells contained arginine. 相似文献
12.
An evaluation of methods for studying bone marrow obtained from patients with acute lymphoblastic leukemia indicates that both directly prepared and cultured cells are necessary for complete karyotypic analysis, but that both synchronized and unsynchronized cultures may not be necessary. 相似文献
13.
14.
15.
16.
Q Yuan W M Jiang D Hollander E Leung J D Watson G W Krissansen 《Biochemical and biophysical research communications》1991,176(3):1443-1449
A cDNA clone encoding the N-terminal sequence of the murine integrin beta 7 subunit, a novel member of the leukocyte cell adhesion molecule subset (Leu-CAM), has been isolated. An N-terminal region of 13 contiguous amino acids deduced from the cDNA shows complete identity with the N-terminus of the 120 kDa subunit of the M290 antigen, a surface molecule found highly expressed on mouse intestinal intraepithelial lymphocytes (IEL). This unexpected result focuses two previously unconnected areas of research and suggests that integrins may have a special role to play in the defence of the gut mucosa. 相似文献
17.
Catherine Bonaïti-Pellié Françoise Clerget-Darpoux Marie-Claude Babron 《Human genetics》1990,86(2):203-208
Summary Although the retinoblastoma gene has been isolated and sequenced, the difference in penetrance and expressivity among families has not yet been fully explained. Balanced chromosomal insertion involving the 13q14 regions has been shown to account for some families with several unaffected carriers. Since there could be cases with karyotypically undetectable insertions, we tested whether this mechanism was general enough to explain the whole difference in expressivity among families. Using 166 pedigrees, reported in nine series available in the literature (including our own), we conclude that balanced insertion cannot entirely explain the familial data, even if we allow for a reduced viability of unbalanced gametes. Other mechanisms are proposed and discussed in this paper. 相似文献
18.
19.
R. Watson 《BMJ (Clinical research ed.)》1997,314(7098):1854
20.