全文获取类型
收费全文 | 2056篇 |
免费 | 246篇 |
出版年
2021年 | 23篇 |
2020年 | 24篇 |
2019年 | 23篇 |
2018年 | 25篇 |
2017年 | 22篇 |
2016年 | 45篇 |
2015年 | 61篇 |
2014年 | 69篇 |
2013年 | 84篇 |
2012年 | 90篇 |
2011年 | 90篇 |
2010年 | 64篇 |
2009年 | 68篇 |
2008年 | 67篇 |
2007年 | 78篇 |
2006年 | 74篇 |
2005年 | 85篇 |
2004年 | 77篇 |
2003年 | 71篇 |
2002年 | 65篇 |
2001年 | 49篇 |
2000年 | 59篇 |
1999年 | 40篇 |
1998年 | 31篇 |
1997年 | 24篇 |
1996年 | 22篇 |
1995年 | 30篇 |
1994年 | 32篇 |
1993年 | 21篇 |
1992年 | 55篇 |
1991年 | 47篇 |
1990年 | 50篇 |
1989年 | 40篇 |
1988年 | 36篇 |
1987年 | 29篇 |
1986年 | 34篇 |
1985年 | 39篇 |
1984年 | 39篇 |
1983年 | 27篇 |
1982年 | 21篇 |
1981年 | 21篇 |
1979年 | 33篇 |
1977年 | 19篇 |
1976年 | 21篇 |
1975年 | 23篇 |
1974年 | 21篇 |
1973年 | 19篇 |
1972年 | 16篇 |
1971年 | 21篇 |
1968年 | 20篇 |
排序方式: 共有2302条查询结果,搜索用时 15 毫秒
1.
2.
3.
The p53 pathway and apoptosis. 总被引:17,自引:0,他引:17
4.
5.
The effects of various anionic phospholipids on the in vitro assembly of MAP2/tubulin microtubules has been examined. We show that the potency to inhibit is related to the polarity of the phospholipids and that this is consistent with a mode of action involving the sequencing of microtubule-associated proteins (MAPs) by nonspecific electrostatic interactions. The inhibitory potency of phosphatidylinositol (PI) is, however, considerably larger than predicted by this model. The effects of PI on MAP2/tubulin microtubule assembly have therefore been examined in greater detail by preparing phosphatidylcholine (PC) liposomes doped with increasing amounts of PI. We show that when the PI is sufficiently dispersed by dilution with PC, it inhibits microtubule assembly by binding to MAP2 with an apparent stoichiometry, after correction for the bilamellar nature of the liposomes, of 1:1 mol.mol-1 PI:MAP2. Furthermore, we show that the Kd of this interaction is in the submicromolar range. 相似文献
6.
7.
A large series of mouse monoclonal antibodies was found to inhibit the proliferation of T-cell growth factor (TCGF)-dependent human T-cell blasts as measured by the incorporation of tritiated thymidine. The specificity of the antibody appeared to be irrelevant for inhibition and two T-cell-specific antibodies did not prevent the absorption of TCGF by treated T cells. It is suggested that the antibodies function by the indirect release of suppressor factors by Fc receptor-bearing TCGF-dependent cells. 相似文献
8.
9.
10.
Porins are pore-forming outer-membrane proteins which serve as a non-specific pathway for the entry of hydrophilic molecules into Gram-negative bacteria. We studied four strains of Haemophilus influenzae that had decreased permeability to chloramphenicol associated with diminished quantities of a 40 kDa major outer-membrane protein. Isogenic pairs of organisms containing and lacking this protein were compared. The latter strains grew more slowly and were less permeable to sucrose and raffinose. They were also more resistant to multiple hydrophilic antibiotics than an isogenic strain containing the 40 kDa protein and were less permeable to penicillin G and chloramphenicol. We conclude that the 40 kDa outer-membrane protein functions as a porin in H. influenzae. 相似文献