全文获取类型
收费全文 | 2350156篇 |
免费 | 171219篇 |
国内免费 | 3331篇 |
专业分类
耳鼻咽喉 | 32049篇 |
儿科学 | 75891篇 |
妇产科学 | 62685篇 |
基础医学 | 348165篇 |
口腔科学 | 63633篇 |
临床医学 | 211343篇 |
内科学 | 457270篇 |
皮肤病学 | 51727篇 |
神经病学 | 185274篇 |
特种医学 | 88006篇 |
外国民族医学 | 489篇 |
外科学 | 353854篇 |
综合类 | 47509篇 |
现状与发展 | 12篇 |
一般理论 | 848篇 |
预防医学 | 182729篇 |
眼科学 | 54325篇 |
药学 | 175103篇 |
11篇 | |
中国医学 | 4575篇 |
肿瘤学 | 129208篇 |
出版年
2021年 | 18980篇 |
2019年 | 19537篇 |
2018年 | 27057篇 |
2017年 | 20357篇 |
2016年 | 22745篇 |
2015年 | 25639篇 |
2014年 | 36094篇 |
2013年 | 53952篇 |
2012年 | 74675篇 |
2011年 | 79407篇 |
2010年 | 47056篇 |
2009年 | 44564篇 |
2008年 | 74608篇 |
2007年 | 79475篇 |
2006年 | 80294篇 |
2005年 | 77777篇 |
2004年 | 74367篇 |
2003年 | 71689篇 |
2002年 | 69362篇 |
2001年 | 108737篇 |
2000年 | 111450篇 |
1999年 | 93494篇 |
1998年 | 26990篇 |
1997年 | 23658篇 |
1996年 | 24054篇 |
1995年 | 22715篇 |
1994年 | 20893篇 |
1993年 | 19712篇 |
1992年 | 72000篇 |
1991年 | 70069篇 |
1990年 | 68391篇 |
1989年 | 65663篇 |
1988年 | 60302篇 |
1987年 | 59125篇 |
1986年 | 55217篇 |
1985年 | 53004篇 |
1984年 | 39311篇 |
1983年 | 33396篇 |
1982年 | 19858篇 |
1979年 | 35866篇 |
1978年 | 25651篇 |
1977年 | 21230篇 |
1976年 | 20332篇 |
1975年 | 21816篇 |
1974年 | 26148篇 |
1973年 | 24802篇 |
1972年 | 23200篇 |
1971年 | 22037篇 |
1970年 | 20247篇 |
1969年 | 19315篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
221.
The aim of the study was to investigate whether hypothermic oxygenated liver perfusion after cold liver preservation resuscitated metabolic parameters and whether this treatment had a benefit for liver viability upon reperfusion.
We preserved rat livers either by cold storage (UW) for 10 h, or by perfusion for 3 h (oxygenated modified UW) after 10 h cold storage. We assessed viability of livers after preservation and after ischemic rewarming + normothermic reperfusion ex vivo . Ten hour cold storage reduced mitochondrial cytochrome oxidase and metabolically depleted the livers. Oxygenated perfusion after cold storage resulted in uploaded cellular energy charge and oxidized mitochondrial cytochrome oxidase. Reperfusion after 10 h cold storage increased formation of superoxid anions, release of cytosolic LDH, lipid peroxidation, caspase activities and led to disruption of sinusoidal endothelial cells. In contrast, reperfusion after 10 h cold storage + 3 h hypothermic oxygenated perfusion resulted in no changes of lipid peroxidation, bile flow, energy charge, total glutathione, LDH release and of caspase activation, as compared to fresh resected livers.
This study demonstrates, that a metabolically depleted liver due to cold storage can be energy recharged by short-termed cold machine perfusion. The machine perfused graft exhibited improved viability and functional integrity. 相似文献
We preserved rat livers either by cold storage (UW) for 10 h, or by perfusion for 3 h (oxygenated modified UW) after 10 h cold storage. We assessed viability of livers after preservation and after ischemic rewarming + normothermic reperfusion ex vivo . Ten hour cold storage reduced mitochondrial cytochrome oxidase and metabolically depleted the livers. Oxygenated perfusion after cold storage resulted in uploaded cellular energy charge and oxidized mitochondrial cytochrome oxidase. Reperfusion after 10 h cold storage increased formation of superoxid anions, release of cytosolic LDH, lipid peroxidation, caspase activities and led to disruption of sinusoidal endothelial cells. In contrast, reperfusion after 10 h cold storage + 3 h hypothermic oxygenated perfusion resulted in no changes of lipid peroxidation, bile flow, energy charge, total glutathione, LDH release and of caspase activation, as compared to fresh resected livers.
This study demonstrates, that a metabolically depleted liver due to cold storage can be energy recharged by short-termed cold machine perfusion. The machine perfused graft exhibited improved viability and functional integrity. 相似文献
222.
R. Watson T. Kozlowski V. Nickeleit J. T. Woosley J. L. Schmitz S. L. Zacks J. H. Fair D. A. Gerber K. A. Andreoni 《American journal of transplantation》2006,6(12):3022-3029
Antibody-mediated rejection (AMR) after liver transplantation is recognized in ABO incompatible and xeno-transplantation, but its role after ABO compatible liver transplantation is controversial. We report a case of ABO compatible liver transplantation that demonstrated clinical, serological and histological signs of AMR without evidence of concurrent acute cellular rejection. AMR with persistently high titers of circulating donor specific antibodies resulted in graft injury with initial centrilobular hepatocyte necrosis, fibroedematous portal expansion mimicking biliary tract outflow obstruction, ultimately resulting in extensive bridging fibrosis. Immunofluorescence microscopy demonstrated persistent, diffuse linear C4d deposits along sinusoids and central veins. Despite intense therapeutic intervention including plasmapheresis, IVIG and rituximab, AMR led to graft failure. We present evidence that an antibody-mediated alloresponse to an ABO compatible liver graft can cause significant graft injury independent of acute cellular rejection. AMR shows distinct histologic changes including a characteristic staining profile for C4d. 相似文献
223.
B. C. Beaudette-Zlatanova B. Whalen D. Zipris H. Yagita J. Rozing H. Groen C. D. Benjamin T. Hunig H. A. Drexhage M. J. Ansari J. Leif J. P. Mordes D. L. Greiner M. H. Sayegh A. A. Rossini 《American journal of transplantation》2006,6(5P1):894-902
Costimulatory signals regulate T-cell activation. To investigate the role of costimulation in autoimmunity and transplantation, we studied the BB rat model of type 1 diabetes. Diabetes-prone BB (BBDP) rats spontaneously develop disease when 55–120 days of age. We observed that two anti-CD28 monoclonal antibodies (mAb) with different functional activities completely prevented diabetes in BBDP rats. Anti-CD154 mAb delayed diabetes, whereas treatment with CTLA4-Ig or anti-CD80 mAb accelerated disease. Anti-CD86 or anti-CD134L mAbs had no effect. Diabetes resistant BB (BBDR) rats are disease-free, but >95% of them develop diabetes after treatment with polyinosinic-polycytidylic acid and an mAb that depletes Treg cells. In the induced BBDR model, anti-CD154 mAb delayed onset of diabetes, whereas CTLA4-Ig, anti-CD134L or either of the anti-CD28 mAbs had little or no effect. In contrast, blockade of the CD134-CD134L pathway was highly effective for preventing autoimmune recurrence against syngeneic islet grafts in diabetic BBDR hosts. Blockade of the CD40-CD154 pathway was also effective, but less so. These data suggest that the effectiveness of costimulation blockade in the treatment of type 1 diabetes is dependent on both the costimulatory pathway targeted and the mechanism of induction, stage, intensity and duration of the pathogenic process. 相似文献
224.
It is important to determine when to use and when to avoid calcineurin inhibitors (CNIs). CNIs are associated with kidney dysfunction in some, but not all, transplant recipients. CNI-sparing protocols have their own drug-specific limitations. Two major clinical series suggest the benefit of routine CNI-sparing approaches, but our review suggests weaknesses in both. Ongoing studies are needed to determine which subgroups of recipients will benefit from CNIs. 相似文献
225.
226.
227.
228.
229.
F Sebastiano G Di Gennaro V Esposito A Picardi R Morace A Sparano A Mascia C Colonnese G Cantore P P Quarato 《Clinical neurophysiology》2006,117(2):341-347
OBJECTIVES: To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS: We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS: In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS: While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE: Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning. 相似文献
230.
Bethe A Scalettar 《The Neuroscientist》2006,12(2):164-176
Neurons and related cell types often contain two major classes of neurosecretory vesicles, synaptic vesicles (SVs) and dense-core granules (DCGs), which store and release distinct cargo. SVs store and release classic neurotransmitters, which facilitate propagation of action potentials across the synaptic cleft, whereas DCGs transport, store, and release hormones, proteins, and neuropeptides, which facilitate neuronal survival, synaptic transmission, and learning. Over the past few years, there has been a major surge in our understanding of many of the key molecular mechanisms underlying cargo release from SVs and DCGs. This surge has been driven largely by the use of fluorescence microscopy (especially total internal reflection fluorescence microscopy) to visualize SVs or DCGs in living cells. This review highlights some of the recent insights into cargo release from neurosecretory vesicles provided by fluorescence microscopy, with emphasis on DCGs. 相似文献