全文获取类型
收费全文 | 534篇 |
免费 | 51篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 15篇 |
妇产科学 | 7篇 |
基础医学 | 47篇 |
口腔科学 | 27篇 |
临床医学 | 51篇 |
内科学 | 109篇 |
皮肤病学 | 8篇 |
神经病学 | 20篇 |
特种医学 | 100篇 |
外科学 | 47篇 |
综合类 | 66篇 |
预防医学 | 31篇 |
眼科学 | 6篇 |
药学 | 36篇 |
中国医学 | 4篇 |
肿瘤学 | 16篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 28篇 |
2012年 | 22篇 |
2011年 | 22篇 |
2010年 | 43篇 |
2009年 | 29篇 |
2008年 | 19篇 |
2007年 | 21篇 |
2006年 | 27篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 18篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 5篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 18篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1968年 | 1篇 |
排序方式: 共有591条查询结果,搜索用时 15 毫秒
51.
目的总结在体外循环辅助下,经右房切口治疗合并下腔静脉血栓形成的布-加氏综合征的治疗经验。方法回顾我院自2002年9月至2010年7月共计49例在体外循环辅助下,经右心房切口治疗合并下腔静脉血栓的布加氏综合征的临床病例和随访资料。结果全组病人均成功的在体外循环辅助下完成经右房切口下腔静脉狭窄段扩张及血栓取出术。术中在手指破膜后再使用3.0×4.0cm球囊进行扩张。围手术期病人无死亡,无急性肺栓塞等严重并发症的发生。术后随访0~36个月,所有病人术后症状明显缓解,腹水及下肢水肿减轻至消失。1例病人术后1年后出现再狭窄,经股静脉行下腔静脉球囊扩张后好转。全组病人术后随访未见有血栓形成。结论在体外循环下,经右房切口对于合并下腔静脉血栓的布-加氏综合征是一种安全有效的治疗方法。 相似文献
52.
53.
Enhancement of erythrocyte superoxide dismutase activity: effects on cellular oxidant defense 总被引:3,自引:0,他引:3
To delineate further the role of superoxide dismutase (SOD) in red blood cell (RBC) oxidant defense, normal human erythrocytes were osmotically lysed and resealed in the presence of varying concentrations of exogenous SOD. This resulted in a dose-dependent increase in SOD activity in the resealed erythrocytes while maintaining nearly normal RBC hemoglobin concentration (less than 10% decrease from the control value), cell volume, and cellular deformability. Surprisingly, a five- or ninefold increase in SOD activity yielded no additional protection against superoxide-generating drugs (phenazine methosulfate or menadione sodium bisulfite). No significant differences were observed between the control and SOD-loaded RBCs in O2-driven methemoglobin formation or generation of thiobarbituric acid-reactive substances. In contrast, RBCs with elevated SOD activity pretreated with sodium azide (to block catalase activity) or 1-chloro-2,4- dinitrobenzene (to deplete reduced glutathione, GSH) showed significantly enhanced methemoglobin generation in response to superoxide generating drugs. No differential response was noted between the control, control-resealed, and SOD-loaded RBCs to oxidants other than superoxide. Based on our results and other data, we conclude that elevated SOD activity may imbalance cellular oxidant defense, resulting in enhanced oxidation due to the accelerated generation of H2O2, the product of O2- dismutation. This effect is significantly exacerbated under conditions in which H2O2 catabolism is altered. 相似文献
54.
Interference with T cell receptor-HLA-DR interactions by Epstein-Barr virus gp42 results in reduced T helper cell recognition 下载免费PDF全文
Ressing ME van Leeuwen D Verreck FA Gomez R Heemskerk B Toebes M Mullen MM Jardetzky TS Longnecker R Schilham MW Ottenhoff TH Neefjes J Schumacher TN Hutt-Fletcher LM Wiertz EJ 《Proceedings of the National Academy of Sciences of the United States of America》2003,100(20):11583-11588
Epstein-Barr virus (EBV) persists lifelong in infected hosts despite the presence of antiviral immunity. Many viral antigens are expressed during lytic infection. Thus, for EBV to spread, it must have evolved effective ways to evade immune recognition. Here, we report that HLA class II-restricted antigen presentation to T helper cells is hampered in the presence of the lytic-phase protein gp42. This interference with T cell activation involves association of gp42 with class II peptide complexes. Using HLA-DR tetramers, we identify a block in T cell receptor (TCR)-class II interactions imposed by gp42 as the underlying mechanism. EBV gp42 sterically clashes with TCR Valpha-domains as visualized by superimposing the crystal structures for gp42-HLA-DR1 and TCR-MHC class II complexes. Blocking TCR recognition provides a previously undescribed strategy for viral immune evasion. 相似文献
55.
The magnetic resonance (MR) relaxation rates of protons were compared in the myelinated and nonmyelinated nerves of the garfish. The long, large olfactory nerve of the garfish, as an easily accessible source of nonmyelinated axons, is uniquely suited for such a comparison. The T1 and T2 measurements revealed distinct and consistent differences between nonmyelinated olfactory nerves and myelinated optic and oculomotor nerves. Comparisons between water content, lipid content, and relaxation rates indicated that the differences in MR properties represent complex differences in the distribution and physical environment of the constituent lipid and water protons. 相似文献
56.
57.
U. Rüb H. Heinsen† E. R. Brunt‡ B. Landwehrmeyer§ W. FA Den Dunnen¶ K. Gierga T. Deller 《Neuropathology and applied neurobiology》2009,35(1):4-15
Recent progress in oculomotor research has enabled new insights into the functional neuroanatomy of the human premotor oculomotor brainstem network. In the present review, we provide an overview of its functional neuroanatomy and summarize the broad range of oculomotor dysfunctions that may occur in Huntington's disease (HD) patients. Although some of these oculomotor symptoms point to an involvement of the premotor oculomotor brainstem network in HD, no systematic analysis of this functional system has yet been performed in brains of HD patients. Therefore, its exact contribution to oculomotor symptoms in HD remains unclear. A possible strategy to clarify this issue is the use of unconventional 100-µm-thick serial tissue sections stained for Nissl substance and lipofuscin pigment (Nissl-pigment stain according to Braak). This technique makes it possible to identify the known nuclei of the premotor oculomotor brainstem network and to study their possible involvement in the neurodegenerative process. Studies applying this morphological approach and using the current knowledge regarding the functional neuroanatomy of this human premotor oculomotor brainstem network will help to elucidate the anatomical basis of the large spectrum of oculomotor dysfunctions that are observed in HD patients. This knowledge may aid clinicians in the diagnosis and monitoring of the disease. 相似文献
58.
59.
60.
A method of automatic exposure termination (AET) for xeromammography has been devised, significantly reducing the rate of repeat exposures due to poor choice of manual exposure factors. AET images are of good quality and are reliably produced. The concept of AET is based on the existence of an optimal transmitted exposure to the selenium plate, which is easily determined experimentally. In routine clinical xeromammography, a repeat rate of 20% was eliminated by the use of AET. 相似文献