全文获取类型
收费全文 | 3249篇 |
免费 | 210篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 28篇 |
2020年 | 17篇 |
2019年 | 34篇 |
2018年 | 50篇 |
2017年 | 44篇 |
2016年 | 64篇 |
2015年 | 115篇 |
2014年 | 123篇 |
2013年 | 190篇 |
2012年 | 231篇 |
2011年 | 219篇 |
2010年 | 133篇 |
2009年 | 149篇 |
2008年 | 226篇 |
2007年 | 210篇 |
2006年 | 181篇 |
2005年 | 183篇 |
2004年 | 192篇 |
2003年 | 176篇 |
2002年 | 165篇 |
2001年 | 68篇 |
2000年 | 54篇 |
1999年 | 65篇 |
1998年 | 31篇 |
1997年 | 28篇 |
1996年 | 20篇 |
1995年 | 35篇 |
1994年 | 19篇 |
1993年 | 22篇 |
1992年 | 43篇 |
1991年 | 30篇 |
1990年 | 39篇 |
1989年 | 28篇 |
1988年 | 38篇 |
1987年 | 27篇 |
1986年 | 23篇 |
1985年 | 26篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 10篇 |
1979年 | 12篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1973年 | 8篇 |
1972年 | 7篇 |
1969年 | 3篇 |
排序方式: 共有3459条查询结果,搜索用时 93 毫秒
1.
2.
3.
4.
Formation of a Tree having a Low Lignin Content 总被引:2,自引:0,他引:2
Received 30 September 2001/ Accepted in revised form 26 October 2001 相似文献
5.
6.
Hiroshi Furukawa 《Phytochemistry》1982,21(7):1771-1773
Two new acridone alkaloids, severifoline and N-methylseverifoline along with the known alkaloids, N-methylatalaphylline, atalaphyllinine and 5-hydroxy-N-methylseverifoline, were isolated from the root bark of Severinia buxifolia. The structures of severifoline and N-methylseverifoline were established by chemical and spectroscopic methods. 相似文献
7.
8.
Excitability changes during collateral inhibition of the goldfish Mauthner cell (M cell) were measured directly by stimulating the cell with current pulses applied through an intracellular electrode. Excitability was suppressed during the extrinsic hyperpolarizing potential (EHP) as well as during the collateral IPSP. The inhibitory effect of the EHP was shown to be comparable in intensity to the effect of the IPSP. Excitability changes in the M cell during collateral IPSP depended on changes in the membrane conductance as well as in the membrane potential. Some simple equations are advanced which describe the excitability change during the IPSP in terms of changes in membrane potential and conductance. It was also found that invasion of antidromic impulses into the M cell was suppressed during the EHP, but not during the collateral IPSP. Conductance increase during the IPSP did not interfere with the invasion of antidromic impulses. 相似文献
9.
10.
Kemala Isnainiasih Mantilidewi Yoji Murata Munemasa Mori Chihiro Otsubo Takenori Kotani Shinya Kusakari Hiroshi Ohnishi Takashi Matozaki 《The Journal of biological chemistry》2014,289(10):6451-6461
Vascular endothelial cells (ECs) are continuously exposed to shear stress (SS) generated by blood flow. Such stress plays a key role in regulation of various aspects of EC function including cell proliferation and motility as well as changes in cell morphology. Vascular endothelial-protein-tyrosine phosphatase (VE-PTP) is an R3-subtype PTP that possesses multiple fibronectin type III-like domains in its extracellular region and is expressed specifically in ECs. The role of VE-PTP in EC responses to SS has remained unknown, however. Here we show that VE-PTP is diffusely localized in ECs maintained under static culture conditions, whereas it undergoes rapid accumulation at the downstream edge of the cells relative to the direction of flow in response to SS. This redistribution of VE-PTP triggered by SS was found to require its extracellular and transmembrane regions and was promoted by integrin engagement of extracellular matrix ligands. Inhibition of actin polymerization or of Cdc42, Rab5, or Arf6 activities attenuated the SS-induced redistribution of VE-PTP. VE-PTP also underwent endocytosis in the static and SS conditions. SS induced the polarized distribution of internalized VE-PTP. Such an effect was promoted by integrin engagement of fibronectin but prevented by inhibition of Cdc42 activity or of actin polymerization. In addition, depletion of VE-PTP by RNA interference in human umbilical vein ECs blocked cell elongation in the direction of flow induced by SS. Our results suggest that the polarized redistribution of VE-PTP in response to SS plays an important role in the regulation of EC function by blood flow. 相似文献