全文获取类型
收费全文 | 165839篇 |
免费 | 11356篇 |
国内免费 | 50篇 |
专业分类
177245篇 |
出版年
2023年 | 893篇 |
2022年 | 1167篇 |
2021年 | 2392篇 |
2020年 | 1999篇 |
2019年 | 2092篇 |
2018年 | 4183篇 |
2017年 | 3727篇 |
2016年 | 5207篇 |
2015年 | 7023篇 |
2014年 | 7158篇 |
2013年 | 9399篇 |
2012年 | 10956篇 |
2011年 | 9972篇 |
2010年 | 6411篇 |
2009年 | 5273篇 |
2008年 | 7861篇 |
2007年 | 7511篇 |
2006年 | 7190篇 |
2005年 | 6718篇 |
2004年 | 6689篇 |
2003年 | 5913篇 |
2002年 | 5156篇 |
2001年 | 4267篇 |
2000年 | 4108篇 |
1999年 | 3328篇 |
1998年 | 1487篇 |
1997年 | 1222篇 |
1996年 | 1297篇 |
1995年 | 1108篇 |
1994年 | 1046篇 |
1993年 | 936篇 |
1992年 | 2137篇 |
1991年 | 1909篇 |
1990年 | 1806篇 |
1989年 | 1868篇 |
1988年 | 1690篇 |
1987年 | 1612篇 |
1986年 | 1507篇 |
1985年 | 1545篇 |
1984年 | 1383篇 |
1983年 | 1098篇 |
1982年 | 909篇 |
1979年 | 1199篇 |
1978年 | 963篇 |
1977年 | 857篇 |
1975年 | 961篇 |
1974年 | 1037篇 |
1973年 | 1023篇 |
1972年 | 863篇 |
1969年 | 855篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
M Lebl E E Sugg G van Binst P Vander Elst D Tourwé J Slaninová V J Hruby 《International journal of peptide and protein research》1987,30(3):318-322
Analogs of deamino-oxytocin and deamino-oxypressin containing a CH2-NH group instead of an amide bond between positions 8 and 9 were synthesized. All tested compounds exhibit significantly lowered biological activities. 相似文献
92.
93.
H. Štorchová 《Biologia Plantarum》1994,36(3):358-358
94.
Is the mitochondrial precursor protein apocytochrome c able to pass a lipid barrier? 总被引:4,自引:0,他引:4
To obtain insight into the role of lipids in the translocation of extramitochondrially synthesized proteins, we studied the ability of apocytochrome c to pass lipid bilayers. With polyacrylamide gel electrophoresis, the digestion of externally added apocytochrome c by trypsin, enclosed in lipid vesicles, was followed. The experiments demonstrate that apocytochrome c is able to pass a lipid barrier and this process shows both a lipid- and protein specificity. The most probable molecular mechanisms involved in this phenomenon are discussed. 相似文献
95.
I de Hurtado A G Osler 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1975,149(3):633-637
The anti-DNP response to DNP-BGG is substantially suppressed in guinea pigs sensitized to DNCB. The degree of antibody suppression varies with the mode of skin sensitization and with the degree of conjugation of the challenging immunogen. Suppression of the anti-HSA response was also induced by the prior injection of CFA. 相似文献
96.
97.
98.
Effect of pharmacological agents on the activity of the circular and longitudinal smooth muscle layers of human fallopian tube ampullar segments 总被引:1,自引:0,他引:1
The in vitro determination of the effects of some pharmacological agents on the outer diameter and axial tension of human Fallopian tube ampullar segments showed that some drugs may act on the circular and longitudinal smooth muscle layers relatively separately. PGF2 alpha elicited an excitatory response in both muscle layers while norepinephrine and isoproterenol decreased the activity. Oxytocin and indomethacin had relatively limited effects on the spontaneous motility of the ampullar segments. The calcium antagonist verapamil inhibited the spontaneous periodic activity. 相似文献
99.
The influence of systemically administered Des-Tyr1-α-endorphin (DTαE), Des-Tyr1-γ-endorphin (DTγE) and haloperidol on electroencephalographic (EEG) activity of the lateral septum complex (LSC) and the frontal cortex was studied in male rats. DTαE (2 μg) significantly increased whereas DTγE (10 μg) significantly decreased the amounts of activity in the 5 Hz band. In addition, DTαE promoted production of 15 - 20 Hz activity, while DTγE decreased the amount of 20 - 30 Hz activity. EEG activity exhibited a marked variability which persisted throughout the recording session following administration of the peptides. Haloperidol markedly decreased the proportion of 10 - 15 Hz activity. The alterations in EEG of the frontal cortex were similar to those in LSC but less pronounced. The differences in the time course and frequency bands affected suggest that the effects of peptides and haloperidol on EEG activity of LSC are not mediated by the same mechanisms. 相似文献
100.