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   4379924篇
  免费   350703篇
  国内免费   14767篇
耳鼻咽喉   60837篇
儿科学   140445篇
妇产科学   114891篇
基础医学   669992篇
口腔科学   118793篇
临床医学   400168篇
内科学   796467篇
皮肤病学   108113篇
神经病学   371475篇
特种医学   170445篇
外国民族医学   758篇
外科学   661345篇
综合类   121724篇
现状与发展   24篇
一般理论   2670篇
预防医学   363448篇
眼科学   101610篇
药学   309820篇
  26篇
中国医学   12011篇
肿瘤学   220332篇
  2021年   56486篇
  2020年   35997篇
  2019年   59066篇
  2018年   74865篇
  2017年   57301篇
  2016年   63479篇
  2015年   76320篇
  2014年   110664篇
  2013年   176373篇
  2012年   126970篇
  2011年   132134篇
  2010年   126829篇
  2009年   128194篇
  2008年   118072篇
  2007年   125643篇
  2006年   134250篇
  2005年   128373篇
  2004年   129541篇
  2003年   119588篇
  2002年   108633篇
  2001年   167098篇
  2000年   162180篇
  1999年   148823篇
  1998年   71795篇
  1997年   67718篇
  1996年   65734篇
  1995年   61129篇
  1994年   55030篇
  1993年   51085篇
  1992年   106694篇
  1991年   101464篇
  1990年   97322篇
  1989年   94877篇
  1988年   87210篇
  1987年   85362篇
  1986年   80268篇
  1985年   78424篇
  1984年   65483篇
  1983年   58238篇
  1982年   47250篇
  1981年   43906篇
  1980年   41135篇
  1979年   55149篇
  1978年   44797篇
  1977年   40016篇
  1976年   36875篇
  1975年   36838篇
  1974年   39645篇
  1973年   37798篇
  1972年   35402篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Cancer Causes & Control - Congenital malformations are strong risk factors for childhood cancer. Our objective was to determine whether cancer survival differs by birth defect status among...  相似文献   
73.
European Surgery - Treatment of pilonidal sinus disease (PSD) requires a tailored approach. A national guideline was published in 2014. The current status of surgical PSD therapy...  相似文献   
74.
In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.  相似文献   
75.
76.
77.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia.  相似文献   
78.
79.
80.
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