全文获取类型
收费全文 | 3995篇 |
免费 | 330篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 84篇 |
妇产科学 | 50篇 |
基础医学 | 670篇 |
口腔科学 | 67篇 |
临床医学 | 339篇 |
内科学 | 908篇 |
皮肤病学 | 61篇 |
神经病学 | 206篇 |
特种医学 | 211篇 |
外科学 | 609篇 |
综合类 | 262篇 |
一般理论 | 4篇 |
预防医学 | 153篇 |
眼科学 | 45篇 |
药学 | 211篇 |
中国医学 | 13篇 |
肿瘤学 | 363篇 |
出版年
2023年 | 25篇 |
2022年 | 68篇 |
2021年 | 117篇 |
2020年 | 74篇 |
2019年 | 84篇 |
2018年 | 96篇 |
2017年 | 90篇 |
2016年 | 86篇 |
2015年 | 94篇 |
2014年 | 140篇 |
2013年 | 135篇 |
2012年 | 213篇 |
2011年 | 219篇 |
2010年 | 135篇 |
2009年 | 161篇 |
2008年 | 208篇 |
2007年 | 208篇 |
2006年 | 189篇 |
2005年 | 171篇 |
2004年 | 174篇 |
2003年 | 152篇 |
2002年 | 110篇 |
2001年 | 120篇 |
2000年 | 90篇 |
1999年 | 111篇 |
1998年 | 84篇 |
1997年 | 71篇 |
1996年 | 54篇 |
1995年 | 49篇 |
1994年 | 50篇 |
1993年 | 33篇 |
1992年 | 69篇 |
1991年 | 63篇 |
1990年 | 57篇 |
1989年 | 72篇 |
1988年 | 61篇 |
1987年 | 67篇 |
1986年 | 41篇 |
1985年 | 48篇 |
1984年 | 20篇 |
1983年 | 20篇 |
1982年 | 28篇 |
1981年 | 19篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 25篇 |
1977年 | 18篇 |
1976年 | 28篇 |
1975年 | 12篇 |
1974年 | 13篇 |
排序方式: 共有4363条查询结果,搜索用时 15 毫秒
1.
Clinical & Experimental Metastasis - 相似文献
2.
Tien‐Yao Tsai Iat‐Lon Leong Ka‐Shun Cheng Lian‐Ru Shiao Tzu‐Hui Su Kar‐Lok Wong Paul Chan Yuk‐Man Leung 《Fundamental & clinical pharmacology》2019,33(1):52-62
A pathological feature in atherosclerosis is the dysfunction and death of vascular endothelial cells (EC). Oxidized low‐density lipoprotein (LDL), known to accumulate in the atherosclerotic arterial walls, impairs endothelium‐dependent relaxation and causes EC apoptosis. A major bioactive ingredient of the oxidized LDL is lysophosphatidylcholine (LPC), which at higher concentrations causes apoptosis and necrosis in various EC. There is hitherto no report on LPC‐induced cytotoxicity in brain EC. In this work, we found that LPC caused cytosolic Ca2+ overload, mitochondrial membrane potential decrease, p38 activation, caspase 3 activation and eventually apoptotic death in mouse cerebral bEND.3 EC. In contrast to reported reactive oxygen species (ROS) generation by LPC in other EC, LPC did not trigger ROS formation in bEND.3 cells. Pharmacological inhibition of p38 alleviated LPC‐inflicted cell death. We examined whether heparin could be cytoprotective: although it could not suppress LPC‐triggered Ca2+ signal, p38 activation and mitochondrial membrane potential drop, it did suppress LPC‐induced caspase 3 activation and alleviate LPC‐inflicted cytotoxicity. Our data suggest LPC apoptotic death mechanisms in bEND.3 might involve mitochondrial membrane potential decrease and p38 activation. Heparin is protective against LPC cytotoxicity and might intervene steps between mitochondrial membrane potential drop/p38 activation and caspase 3 activation. 相似文献
3.
4.
Akira Sawaki Nobumasa Mizuno Kuniyuki Takahashi Tsuneya Nakamura Masahiro Tajika Hiroki Kawai Toshifumi Isaka Hiroshi Imaoka Yasuyuki Okamoto Masatoshi Aoki Hiroyuki Inoue Ahmed AS Salem Yasushi Yatabe Kenji Yamao 《Digestive endoscopy》2006,18(1):40-44
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed. 相似文献
5.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1
6.
7.
An unusual, elongated, refractile cell morphology was observed in keratinocytes cultured from three patients with non-lethalis forms of junctional epidermolysis bullosa (JEB). To determine whether these changes might be related to altered cell adhesion, keratinocyte strains established from one patient were examined for adhesive, structural, and functional characteristics. JEB keratinocytes expressed keratin tonofilaments, as determined by staining with AE1 monoclonal antibodies and direct observation of tonofilaments by electron microscopy. JEB keratinocytes showed diminished cell-substratum adhesions, judged by interference reflection microscopy. Areas of diminished cell-substratum adhesion corresponded to F-actin-rich cell adhesions (focal adhesions) and not to cellular areas that abundantly express hemidesmosomal antigens. Analysis of cell-substratum adhesion by electron microscopy revealed extensive areas of cell-substratum separation in JEB keratinocytes that were not present in normal keratinocytes maintained in serum-free medium. Normal keratinocytes displayed numerous regions of focal contact between the ventral plasma membrane and the culture substratum, but these structures were not seen in JEB keratinocytes. Bundled actin filaments (stress fibers) were greatly diminished in expected regions of cell-substratum adhesion in JEB keratinocytes and, instead, displayed disorganized individual filaments. The growth rate of JEB keratinocytes was quite slow in culture, with a population doubling time of 2.7 d versus 1.5 d for normal keratinocytes under identical conditions. JEB keratinocytes also displayed a reduced ability to aggregate into colonies upon exposure to medium with increased extracellular calcium. JEB keratinocytes thus display adhesive, structural, and functional abnormalities that suggest this cell type may be central to the pathogenesis of junctional epidermolysis bullosa. Study of affected keratinocytes could be important to characterize associated molecular pathologies. 相似文献
8.
9.
10.