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   4933358篇
  免费   393245篇
  国内免费   15602篇
耳鼻咽喉   69204篇
儿科学   158209篇
妇产科学   130172篇
基础医学   741748篇
口腔科学   137265篇
临床医学   454543篇
内科学   902476篇
皮肤病学   117185篇
神经病学   413893篇
特种医学   193683篇
外国民族医学   968篇
外科学   741409篇
综合类   138962篇
现状与发展   24篇
一般理论   2813篇
预防医学   411705篇
眼科学   115819篇
药学   352184篇
  25篇
中国医学   12994篇
肿瘤学   246924篇
  2021年   57014篇
  2019年   59466篇
  2018年   76332篇
  2017年   58157篇
  2016年   64549篇
  2015年   77017篇
  2014年   111552篇
  2013年   177342篇
  2012年   140757篇
  2011年   148665篇
  2010年   131268篇
  2009年   131204篇
  2008年   133944篇
  2007年   143848篇
  2006年   151310篇
  2005年   145578篇
  2004年   146309篇
  2003年   136130篇
  2002年   124771篇
  2001年   197282篇
  2000年   194227篇
  1999年   174324篇
  1998年   75901篇
  1997年   70611篇
  1996年   68796篇
  1995年   64368篇
  1994年   58200篇
  1993年   54014篇
  1992年   128577篇
  1991年   123392篇
  1990年   118830篇
  1989年   115377篇
  1988年   106270篇
  1987年   104320篇
  1986年   98414篇
  1985年   95822篇
  1984年   77788篇
  1983年   68456篇
  1982年   51632篇
  1981年   47710篇
  1980年   44728篇
  1979年   67689篇
  1978年   53048篇
  1977年   46608篇
  1976年   43239篇
  1975年   44063篇
  1974年   48990篇
  1973年   46934篇
  1972年   43930篇
  1971年   40624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