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   4937008篇
  免费   393718篇
  国内免费   15605篇
耳鼻咽喉   69289篇
儿科学   158289篇
妇产科学   130221篇
基础医学   742634篇
口腔科学   137413篇
临床医学   455319篇
内科学   902523篇
皮肤病学   117302篇
神经病学   414565篇
特种医学   193788篇
外国民族医学   971篇
外科学   741849篇
综合类   139060篇
现状与发展   25篇
一般理论   2814篇
预防医学   411485篇
眼科学   115934篇
药学   352559篇
  23篇
中国医学   13025篇
肿瘤学   247243篇
  2021年   57102篇
  2019年   59595篇
  2018年   76426篇
  2017年   58279篇
  2016年   64661篇
  2015年   77124篇
  2014年   111708篇
  2013年   177539篇
  2012年   141368篇
  2011年   149444篇
  2010年   131413篇
  2009年   131352篇
  2008年   134478篇
  2007年   144352篇
  2006年   151836篇
  2005年   146090篇
  2004年   146769篇
  2003年   136556篇
  2002年   125204篇
  2001年   197332篇
  2000年   194297篇
  1999年   174388篇
  1998年   75922篇
  1997年   70640篇
  1996年   68794篇
  1995年   64364篇
  1994年   58212篇
  1993年   54015篇
  1992年   128614篇
  1991年   123420篇
  1990年   118871篇
  1989年   115410篇
  1988年   106311篇
  1987年   104356篇
  1986年   98461篇
  1985年   95864篇
  1984年   77800篇
  1983年   68480篇
  1982年   51638篇
  1981年   47735篇
  1980年   44738篇
  1979年   67709篇
  1978年   53064篇
  1977年   46622篇
  1976年   43255篇
  1975年   44069篇
  1974年   48999篇
  1973年   46942篇
  1972年   43946篇
  1971年   40626篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
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   
83.
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   
84.
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   
85.
86.
87.
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   
88.
89.
90.
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