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   61116篇
  免费   5677篇
  国内免费   3430篇
耳鼻咽喉   513篇
儿科学   874篇
妇产科学   1005篇
基础医学   7019篇
口腔科学   1079篇
临床医学   7131篇
内科学   9872篇
皮肤病学   733篇
神经病学   2915篇
特种医学   2523篇
外国民族医学   34篇
外科学   7335篇
综合类   9064篇
现状与发展   15篇
一般理论   16篇
预防医学   3964篇
眼科学   1486篇
药学   6517篇
  53篇
中国医学   3084篇
肿瘤学   4991篇
  2024年   177篇
  2023年   843篇
  2022年   2080篇
  2021年   2868篇
  2020年   2067篇
  2019年   1898篇
  2018年   2031篇
  2017年   1806篇
  2016年   1796篇
  2015年   2493篇
  2014年   3155篇
  2013年   3172篇
  2012年   4448篇
  2011年   4723篇
  2010年   3067篇
  2009年   2513篇
  2008年   3362篇
  2007年   3422篇
  2006年   3174篇
  2005年   2958篇
  2004年   2391篇
  2003年   2208篇
  2002年   2002篇
  2001年   1666篇
  2000年   1596篇
  1999年   1439篇
  1998年   774篇
  1997年   780篇
  1996年   630篇
  1995年   530篇
  1994年   463篇
  1993年   313篇
  1992年   506篇
  1991年   412篇
  1990年   388篇
  1989年   345篇
  1988年   274篇
  1987年   260篇
  1986年   205篇
  1985年   160篇
  1984年   117篇
  1983年   84篇
  1982年   60篇
  1981年   73篇
  1980年   39篇
  1979年   72篇
  1978年   37篇
  1974年   36篇
  1973年   33篇
  1972年   41篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
医源性胆管狭窄X线表现   总被引:1,自引:0,他引:1  
本文报道了13例医源性胆管狭窄,分析其影像表现。特点为:环形狭窄;线样狭窄,包括规则的和不规则的线样狭窄;闭塞性狭窄;胆管闭塞和胆管中断分离。ERCT和PCT对狭窄的形态,位置及长度显示优于CT和US。  相似文献   
2.
3.
4.
5.
An immunofluorescent (IF) method that detects Burkholderia pseudomallei in clinical specimens within 10 min was devised. The results of this rapid method and those of an existing IF method were prospectively compared with the culture results for 776 specimens from patients with suspected melioidosis. The sensitivities of both IF tests were 66%, and the specificities were 99.5 and 99.4%, respectively.  相似文献   
6.
BACKGROUND: Oral submucous fibrosis (OSF) is a chewing habit-related pre-cancerous condition of the oral mucosa affecting predominantly south Asians. It is histopathologically characterized by epithelial atrophy and fibrosis of the subepithelial connective tissue. Fibrosis extends all the way into the muscle layer, leading to difficulty in mouth opening. However, the dynamics of extracellular matrix (ECM) remodeling with OSF progression is largely unknown. METHODS: Forty biopsy specimens of OSF and 10 of normal buccal mucosa were examined for expression/deposition modes of eight ECM molecules by histochemistry, immunohistochemistry, and in situ hybridization. RESULTS: In the early stage of OSF, tenascin, perlecan, fibronectin, collagen type III were characteristically enhanced in the lamina propria and the submucosal layer. In the intermediate stage, the ECM molecules mentioned above and elastin were extensively and irregularly deposited around muscle fibers. In the advanced stage, such ECM depositions decreased and were entirely replaced with collagen type I only. Their gene expression levels varied with progression of fibrosis, but the mRNA signals were confirmed in fibroblasts in the submucosal fibrotic areas. CONCLUSIONS: The results indicate that the ECM remodeling steps in OSF are similar to each phase of usual granulation tissue formation. Restricted mouth opening may be a result of loss of variety of ECM molecules including elastin into the homogeneity of collagen type I replacing muscle fibers.  相似文献   
7.
8.
Although many monoclonal antibodies have been made in human colon cancer, none of them are from the Chinese species. Recently, a colon cancer cell line CC-M2 established from a Chinese patient has been completely characterized and used as immunogen to produce monoclonal antibodies. Monoclonal antibodies were produced by standard hybridoma technique. The fusion rate was 95.8%. An isotype IgG1 of high proliferation named as Sam-2 was used in this study. The titers were measured around 10(4). Further studies on MoAb Sam-2 through indirect immunofluorescent and immunoperoxidase tests revealed its good specificity and sensitivity in colorectal cancer tissue. In CEA study, the result indicated that Sam-2 may react on a non-CEA related antigen. For further clinical application, the antigen was identified as a glycoprotein by chemical resistant test. In preliminary studies using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting techniques, Sam-2 could recognize two closed antigens or a dimer antigen with molecular weight 25.2 and 27 Kd respectively.  相似文献   
9.
MK-679 (R(?)-3-((3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)(3-(dimethylamino)-3-oxopropyl)thio)methyl)thio(propanoic acid) is a potent and specific LTD4-receptor antagonist. The disposition of MK-679 was investigated in a three-way crossover study in 12 healthy males receiving single intravenous doses of 75, 250, and 500 mg of MK-679. A greater than proportional increase in the area under the plasma concentration—time curve of MK-679 was observed with increase in dose. The plasma concentration data for each subject fitted well to the differential equations for a two-compartment model with linear tissue distribution and Michaelis-Menten elimination from the central compartment, indicating that the elimination of MK-679 in humans is saturable. In a previous study, the disposition of MK-679 in humans was also dose-dependent when given together with its S(+)-isomer, L-668,018. Thus, the disposition of MK-679 in humans is dose-dependent regardless of the presence of its stereoisomer. Also, the bioavailability of MK-679 was determined in six healthy males receiving simultaneously an oral dose of 250 mg of MK-679 and intravenous infusion of 1 mg 14C-MK-679. Results of this study indicate that the oral bioavailability of MK-679 is nearly quantitative.  相似文献   
10.
W C Cheng  A D Wang 《Neurosurgery》1990,27(5):802-805
Carotid-cavernous sinus fistulas are not rare, but they have never been reported in association with persistent primitive trigeminal artery. We recently encountered such a case. The Jaeger-Hamby procedure was employed, with mandatory occlusion of the primitive trigeminal artery.  相似文献   
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