首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12247篇
  免费   654篇
  国内免费   44篇
耳鼻咽喉   228篇
儿科学   397篇
妇产科学   227篇
基础医学   1448篇
口腔科学   329篇
临床医学   765篇
内科学   3172篇
皮肤病学   409篇
神经病学   766篇
特种医学   262篇
外国民族医学   1篇
外科学   1892篇
综合类   159篇
一般理论   4篇
预防医学   858篇
眼科学   305篇
药学   900篇
中国医学   62篇
肿瘤学   761篇
  2023年   68篇
  2022年   121篇
  2021年   342篇
  2020年   175篇
  2019年   328篇
  2018年   498篇
  2017年   286篇
  2016年   285篇
  2015年   306篇
  2014年   390篇
  2013年   539篇
  2012年   897篇
  2011年   981篇
  2010年   454篇
  2009年   397篇
  2008年   794篇
  2007年   792篇
  2006年   813篇
  2005年   750篇
  2004年   678篇
  2003年   605篇
  2002年   553篇
  2001年   192篇
  2000年   212篇
  1999年   197篇
  1998年   67篇
  1997年   52篇
  1996年   61篇
  1995年   51篇
  1994年   47篇
  1993年   22篇
  1992年   79篇
  1991年   71篇
  1990年   66篇
  1989年   67篇
  1988年   50篇
  1987年   69篇
  1986年   57篇
  1985年   47篇
  1984年   42篇
  1983年   43篇
  1982年   32篇
  1981年   27篇
  1980年   21篇
  1979年   34篇
  1978年   23篇
  1977年   21篇
  1975年   20篇
  1974年   36篇
  1973年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Intramedullary epidermoid cysts of the spinal cord are rare tumors, especially those not associated with spinal dysraphism. About 50 cases have been reported in the literature. Of these, only seven cases have had magnetic resonance imaging (MRI) studies. We report two cases of spinal intramedullary epidermoid cysts with MR imaging. Both were not associated with spina bifida. In one patient, the tumor was located at D4 vertebral level; while in the other, within the conus medullaris. The clinical features, MRI characteristics and surgical treatment of intramedullary epidermoid cyst are presented with relevant review of the literature.  相似文献   
12.
Anti-rheumatic therapy has been targeted against the symptoms arising from chronic inflammation of the joint. This has resulted in the extensive use of non-steroidal anti-inflammatory drugs. It is now becoming apparent that these agents have no beneficial effect on disease progression. This mini review concentrates on the formation and maintenance of pannus, the granulomatous tissue responsible for cartilage and bone erosion. This reveals a number of possible therapeutic targets. Protease inhibitors could be used to interfere with the degradatory processes. The diverse functions of endothelial cells suggest oedema formation, cell accumulation and supply of nutrients to the granulomatous tissue could all be targeted by appropriate therapy. Alternatively the immune processes that control pannus formation and state of activation could be regulated by interfering with antigen presentation and the cytokine network.  相似文献   
13.

Background  

Bortezomib, a proteasome-specific inhibitor, has emerged as a promising cancer therapeutic agent. However, development of resistance to bortezomib may pose a challenge to effective anticancer therapy. Therefore, characterization of cellular mechanisms involved in bortezomib resistance and development of effective strategies to overcome this resistance represent important steps in the advancement of bortezomib-mediated cancer therapy.  相似文献   
14.
The pathogenic mechanisms of accelerated graft fibrosis in hepatitis C recurrence after liver transplantation (LT) are not well established. The aim of the study was to assess whether a greater activation of hepatic stellate cells (HSC), the major collagen-producing cells in the liver, can occur in these patients as compared to non-LT patients with chronic hepatitis C. We determined the amount of activated HSC by computer-based morphometric analysis of alpha-smooth muscle actin (alphaSMA)-positive cells and the hepatic TGFbeta(1) expression by immunohistochemistry in 46 LT patients with hepatitis C recurrence, 35 non-LT patients with chronic hepatitis C, and 16 controls. Hepatic alphaSMA and TGFbeta(1) expression was higher in LT patients with hepatitis C recurrence than in controls and was correlated with fibrosis stage and progression rate. No significant difference in alphaSMA and TGFbeta(1) expression was observed between LT and non-LT patients with hepatitis C, with the exception of a higher transforming growth factor beta-1 (TGFbeta(1)) expression in non-LT patients in the early stages of fibrosis. LT patients receiving cyclosporine (CsA) or tacrolimus (FK) had a similar fibrosis progression rate and alphaSMA and TGFbeta(1) expression. In conclusion, the accelerated fibrosis observed in LT patients with hepatitis C recurrence does not seem to be related to a greater amount of activated HSC and TGFbeta(1) expression in the grafts of these patients as compared to non-LT patients with chronic hepatitis C. In LT patients, the amount of activated HSC and TGFbeta(1) expression correlated with fibrosis stage and progression, without any apparent influence of the type of calcineurin inhibitor administered.  相似文献   
15.
The study was undertaken to analyze the basal and metoclopramide-stimulated serum PRL levels in healthy parous women users (group 1, n = 12) and non-users (group 2, n = 12) of a TCu-380 IUD. All women had regular menses and were studied between days 18 to 22 of their cycle; none had lactated nor regularly ingested any type of medication during the last six months. After a 10-12 hour overnight fast, peripheral venous blood samples were obtained through an indwelling catheter at -30, -15 and 0 minutes and at 60, 90 and 120 minutes after oral metoclopramide (10 mg). There were no significant differences in serum PRL between both groups, in basal levels nor throughout the test, whether analyzing the mean values at each sampling time, the sum of PRL levels from 60-120 minutes, or the peak levels. No correlation was observed between PRL levels and any of the clinical or obstetric characteristics of the women in both groups. Serum progesterone was greater than or equal to 4.0 ng/ml in all women. Thus, the use of alpha TCu-380 IUD did not induce any significant changes in basal nor in stimulated serum PRL levels.  相似文献   
16.
17.
18.
19.
Cationic Lipid-Based Gene Delivery Systems: Pharmaceutical Perspectives   总被引:4,自引:0,他引:4  
Gene delivery systems are designed to control the location of administered therapeutic genes within a patient's body. Successful in vivo gene transfer may require (i) the condensation of plasmid and its protection from nuclease degradation, (ii) cellular interaction and internalization of condensed plasmid, (iii) escape of plasmid from endosomes (if endocytosis is involved), and (iv) plasmid entry into cell nuclei. Expression plasmids encoding a therapeutic protein can be, for instance, complexed with cationic liposomes or micelles in order to achieve effective in vivo gene transfer. A thorough knowledge of pharmaceutics and drug delivery, bio-engineering, as well as cell and molecular biology is required to design optimal systems for gene therapy. This mini-review provides a critical discussion on cationic lipid-based gene delivery systems and their possible uses as pharmaceuticals.  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号