全文获取类型
收费全文 | 34901篇 |
免费 | 9245篇 |
国内免费 | 181篇 |
专业分类
耳鼻咽喉 | 330篇 |
儿科学 | 763篇 |
妇产科学 | 736篇 |
基础医学 | 6568篇 |
口腔科学 | 1138篇 |
临床医学 | 4835篇 |
内科学 | 8338篇 |
皮肤病学 | 674篇 |
神经病学 | 3415篇 |
特种医学 | 2012篇 |
外科学 | 7234篇 |
综合类 | 424篇 |
现状与发展 | 1篇 |
一般理论 | 18篇 |
预防医学 | 3629篇 |
眼科学 | 577篇 |
药学 | 1962篇 |
1篇 | |
中国医学 | 21篇 |
肿瘤学 | 1651篇 |
出版年
2021年 | 506篇 |
2020年 | 360篇 |
2018年 | 536篇 |
2017年 | 504篇 |
2016年 | 713篇 |
2015年 | 1058篇 |
2014年 | 1723篇 |
2013年 | 2519篇 |
2012年 | 1237篇 |
2011年 | 1164篇 |
2010年 | 1472篇 |
2009年 | 1567篇 |
2008年 | 1016篇 |
2007年 | 848篇 |
2006年 | 970篇 |
2005年 | 876篇 |
2004年 | 772篇 |
2003年 | 722篇 |
2002年 | 795篇 |
2001年 | 640篇 |
2000年 | 545篇 |
1999年 | 733篇 |
1998年 | 923篇 |
1997年 | 867篇 |
1996年 | 894篇 |
1995年 | 855篇 |
1994年 | 738篇 |
1993年 | 700篇 |
1992年 | 713篇 |
1991年 | 696篇 |
1990年 | 625篇 |
1989年 | 700篇 |
1988年 | 730篇 |
1987年 | 699篇 |
1986年 | 667篇 |
1985年 | 699篇 |
1984年 | 640篇 |
1983年 | 641篇 |
1982年 | 709篇 |
1981年 | 667篇 |
1980年 | 635篇 |
1979年 | 618篇 |
1978年 | 604篇 |
1977年 | 610篇 |
1976年 | 524篇 |
1975年 | 460篇 |
1974年 | 427篇 |
1973年 | 414篇 |
1972年 | 417篇 |
1971年 | 369篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
122.
123.
Inhibition of angiogenesis by antibody blocking the action of proangiogenic high-molecular-weight kininogen 总被引:7,自引:1,他引:6
R. W. Colman R. A. Pixley I. M. Sainz J. S. Song I. Isordia-Salas S. N. Muhamed † J. A. Powell Jr † S. A. Mousa† 《Journal of thrombosis and haemostasis》2003,1(1):164-170
Summary. Previously we demonstrated that domain 5 (D5) of high-molecular-weight kininogen (HK) inhibits neovascularization in the chicken chorioallantoic membrane (CAM) assay and further found that kallikrein cleaved HK (HKa) inhibited FGF2-and VEGF-induced neovascularization, and thus was antiangiogenic. In this study, we sought to demonstrate whether uncleaved HK stimulates neovascularization and thus is proangiogenic. The chick chorioallantoic membrane was used as an in ovo assay of angiogenesis. Low-molecular-weight kininogen stimulates angiogenesis, indicating that D5 is not involved. Bradykinin stimulates neovascularization equally to HK and LK and is likely to be responsible for the effect of HK. A murine monoclonal antibody to HK (C11C1) also recognizes a similar component in chicken plasma as detected by surface plasmon resonance. Angiogenesis induced by FGF2 and VEGF is inhibited by this monoclonal antibody and is a more potent inhibitor of neovascularization induced by VEGF than an integrin αv β3 antibody (LM 609). Our postulate that C11C1 inhibits the stimulation of angiogenesis by HK was confirmed when either C11C1 or D5 completely inhibited angiogenesis in the CAM induced by HK. Growth of human fibrosarcoma (HT-1080) on the CAM was inhibited by GST-D5 and C11C1. These results indicate HK is proangiogenic probably by releasing bradykinin and that a monoclonal antibody directed to HK could serve as an antiangiogenic agent with a potential for inhibiting tumor angiogenesis and other angiogenesis-mediated disorders. 相似文献
124.
The intrauterine position occupied by a rodent fetus influences the amount of testosterone to which it is exposed before birth. Animals that are gestated between two male fetuses (2M) are exposed to higher circulating levels of testosterone than are animals positioned between two female fetuses (2F) and there are reliable differences in the reproductive physiology and behavior of 2M and 2F animals when adult. To determine whether intrauterine position modifies development of the central nervous system, we examined the sexually dimorphic spinal nucleus of the bulbocavernosus (SNB) in male and female gerbils from known intrauterine positions. We found that adult 2M female gerbils had 16% more SNB motoneurons than did 2F females. 2M males did not differ from 2F males in SNB motoneuron number, but the bulbocavernosus muscle, which is innervated by SNB motoneurons, was approximately 50% larger in 2M than in 2F males. These data indicate that intrauterine position can influence the morphology of the sexually dimorphic SNB neuromuscular system. 相似文献
125.
Phosphorylated Mr 32,000 dopamine- and cAMP-regulated phosphoprotein inhibits Na+,K(+)-ATPase activity in renal tubule cells. 总被引:3,自引:2,他引:1
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A Aperia J Fryckstedt L Svensson H C Hemmings Jr A C Nairn P Greengard 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(7):2798-2801
Dopamine inhibits Na+,K(+)-ATPase activity in several renal tubule segments and thereby regulates urinary Na+ excretion. We now show that a phosphopeptide of 31 amino acids, corresponding to residues 8-38 of the protein phosphatase inhibitor DARPP-32 (dopamine- and cAMP-regulated phosphoprotein of Mr 32,000), mimics the inhibitory action of dopamine on Na+,K(+)-ATPase activity in renal tubule cells from the ascending limb of the loop of Henle. The dephosphorylated form of the peptide is ineffective. The results indicate that dopamine acts through a protein phosphorylation pathway to regulate the activity of an ion pump. In addition, the data suggest that inhibition of protein phosphatase 1 by phophorylated DARPP-32 is a component of the mechanism by which dopamine regulates urinary Na+ excretion. 相似文献
126.
127.
G F Needham R R Pfeiffer G L Engel B S Rutherford D J Allen 《Journal of pharmaceutical sciences》1992,81(10):1012-1014
During the development of a silicone rubber implant for the delivery of estradiol 17-beta some batches of implants made from a certain lot of commercial estradiol inexplicably developed surface crystals of estradiol after several days of storage. An impurity profile was obtained for 28 lots of estradiol by a newly developed HPLC method. One or more impurities may have had a role in the spontaneous crystal growth on the surface of the implants, because the one lot of estradiol that initially had surface crystals on aging produced acceptable implants after multiple recrystallizations. Attempts to isolate suspected impurities for characterization were unsuccessful. During the manufacture of the implants, temperatures sufficient to melt the estradiol (mp, 173-179 degrees C) were used. It was expected that, upon implant cooling, melted impure estradiol would form a thermodynamically more active (i.e., noncrystalline) physical form. This metastable form could have migrated to the implant surface, where ambient conditions favored crystallization. Because melted estradiol of a higher purity tended to crystallize more readily, it was less likely to form a glass upon cooling. The phenomenon of surface crystallization was limited to one lot of estradiol with the highest level of impurities. Data from differential scanning calorimetry studies supported this conclusion. 相似文献
128.
James E. Salter Jr. Donald Gibson Nelson G. Ord ez Bruce Mackay 《Ultrastructural pathology》1995,19(4):305-310
A 7-cm anterior mediastinal tumor in an 80-year-old woman was found by light and electron microscopy to be a neuroblastoma. Immunoreactivity for neuron-specific enolase, synaptophysin, and chromogranin supported the diagnosis. Neuroblastoma is an uncommon tumor in adults and we are not aware of a previous report of such a tumor in a patient of this age. 相似文献
129.
18 patients (20 knee joints) were operated for Osgood-Schlatter disease. 12 patients (14 knee joints) had a follow-up of 2.4 years (0.5-13.5) after operation. The informations of the other patients were taken from our clinical data. 1 month (0.5-24) after operation 13 patients (15 knee joints) were painfree. In 5 cases there were still complaints, but 3 of them were improved by operation. One patient, who was operated on both knees, had no change after operation. The failures are analysed and interpreted concerning their pathogenesis. With help of our results the different operation methods of the literature are discussed. 相似文献
130.