全文获取类型
收费全文 | 312篇 |
免费 | 17篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 8篇 |
妇产科学 | 2篇 |
基础医学 | 29篇 |
口腔科学 | 5篇 |
临床医学 | 18篇 |
内科学 | 53篇 |
皮肤病学 | 13篇 |
神经病学 | 16篇 |
特种医学 | 58篇 |
外科学 | 25篇 |
综合类 | 38篇 |
预防医学 | 20篇 |
眼科学 | 10篇 |
药学 | 19篇 |
1篇 | |
肿瘤学 | 14篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 15篇 |
2011年 | 10篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 15篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 21篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 12篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1988年 | 2篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有330条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Neulen J; Raczek S; Pogorzelski M; Grunwald K; Yeo TK; Dvorak HF; Weich HA; Breckwoldt M 《Molecular human reproduction》1998,4(3):203-206
Vascularization is a prominent event during corpus luteum formation,
providing low density lipoproteins for steroid biosynthesis and enabling
transport of secreted steroids. The process of vascularization is
controlled by specific regulators. Vascular endothelial growth factor
(VEGF), otherwise named vascular permeability factor (VPF), induces
endothelial cell proliferation as well as angiogenesis in vivo and
increases capillary permeability. Here we report the expression of VEGF/VPF
mRNA by cultured human luteinized granulosa cells (GC) for at least 10
days. Without HCG VEGF/VPF expression declined after day 4 and by day 10
was reduced to approximately 30% of the value at day 4. However, after
culture in the presence of 1 U/ml human chorionic gonadotrophin (HCG),
expression of VEGF/VPF mRNA by GC was four times greater than control
experiments by day 10, and increased 100% from day 4 to day 10.
Simultaneously, HCG supplementation increased VEGF/VPF secretion by GC.
Medium VEGF/VPF on day 3 was 13 pM without and 11 pM with HCG. Medium
VEGF/VPF on day 10 was 6 pM without HCG and 29 pM with HCG. These results
suggest that vascularization of the corpus luteum is induced by
HCG-mediated effects of VEGF/VPF.
相似文献
6.
In-vitro vasoreactivity to extracellular potassium (Ko+) was tested in isolated human pial and mesenteric arteries as well as basilar and mesenteric arteries from rabbits and rats. Contractions were induced by stepwise increases in [K+]o and were measured isometrically with a force-displacement transducer, in small-volume organ baths. Significant differences between species as well as between regions were found. The threshold of [K+]o for eliciting contraction in human cerebral arteries in hyperosmotic solutions was 10 mM, in rabbit cerebral arteries 17 mM and in rat cerebral arteries 27 mM. The threshold concentration for contraction in mesenteric arteries was significantly higher compared to cerebral arteries in humans and rabbits, but lower in rats: 20 mM in humans, 26 mM in rabbits and 25 mM in rats. In all species the contractile amplitudes were significantly higher in both cerebral and mesenteric arteries when [K+]o was increased under isotonic conditions in the buffer solution than when hyperosomolality was created. This difference increased with increasing hyperosmolality. In hyperosmotic solutions, the EC50 for [K+]o was lower in cerebral and mesenteric arteries from man than in vessels from rabbit and rat. When the solutions were isotonic, this pattern was seen only in mesenteric arteries. It is concluded that significant species and regional differences in vascular responses to [K+]o exist. Considering that [K+]o is increased in cerebral ischaemia, the observed significantly lower threshold for K+-induced contractions in human cerebral arteries may be of importance, especially in human cerebral ischaemic events. 相似文献
7.
Paredes AM Ferreira D Horton M Saad A Tsuruta H Johnston R Klimstra W Ryman K Hernandez R Chiu W Brown DT 《Virology》2004,324(2):373-386
Alphaviruses have the ability to induce cell-cell fusion after exposure to acid pH. This observation has served as an article of proof that these membrane-containing viruses infect cells by fusion of the virus membrane with a host cell membrane upon exposure to acid pH after incorporation into a cell endosome. We have investigated the requirements for the induction of virus-mediated, low pH-induced cell-cell fusion and cell-virus fusion. We have correlated the pH requirements for this process to structural changes they produce in the virus by electron cryo-microscopy. We found that exposure to acid pH was required to establish conditions for membrane fusion but that membrane fusion did not occur until return to neutral pH. Electron cryo-microscopy revealed dramatic changes in the structure of the virion as it was moved to acid pH and then returned to neutral pH. None of these treatments resulted in the disassembly of the virus protein icosahedral shell that is a requisite for the process of virus membrane-cell membrane fusion. The appearance of a prominent protruding structure upon exposure to acid pH and its disappearance upon return to neutral pH suggested that the production of a "pore"-like structure at the fivefold axis may facilitate cell penetration as has been proposed for polio (J. Virol. 74 (2000) 1342) and human rhino virus (Mol. Cell 10 (2002) 317). This transient structural change also provided an explanation for how membrane fusion occurs after return to neutral pH. Examination of virus-cell complexes at neutral pH supported the contention that infection occurs at the cell surface at neutral pH by the production of a virus structure that breaches the plasma membrane bilayer. These data suggest an alternative route of infection for Sindbis virus that occurs by a process that does not involve membrane fusion and does not require disassembly of the virus protein shell. 相似文献
8.
Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee. 相似文献
9.
Renal transplant (RT) is now a therapy of choice for end stage renal disease (ESRD). The Nephrology Unit, Asvini started functioning in Dec 90 and to date 1298 sittings of hemodialysis have been given to 45 patients. Of these, 35 were in ESRD and 11 patients underwent renal transplantation at this hospital during the period Jan 91 – Dec 93. One patient expired after 18 months of transplantation due to infection. Early experience in screening patients for RT, use of immunosuppression, management of rejection episodes and protocol are presented with special emphasis on its relevance to the Armed Forces.KEY WORDS: Transplantation, Renal Failure, Immunosuppression, Rejection 相似文献
10.