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   4920780篇
  免费   392934篇
  国内免费   15562篇
耳鼻咽喉   69149篇
儿科学   158086篇
妇产科学   130097篇
基础医学   740580篇
口腔科学   137154篇
临床医学   453127篇
内科学   898412篇
皮肤病学   117069篇
神经病学   413284篇
特种医学   193404篇
外国民族医学   968篇
外科学   739747篇
综合类   138860篇
现状与发展   24篇
一般理论   2810篇
预防医学   410172篇
眼科学   115623篇
药学   351557篇
  21篇
中国医学   12986篇
肿瘤学   246146篇
  2021年   56862篇
  2019年   59329篇
  2018年   76147篇
  2017年   58062篇
  2016年   64463篇
  2015年   76886篇
  2014年   111399篇
  2013年   177110篇
  2012年   140269篇
  2011年   148184篇
  2010年   130977篇
  2009年   130969篇
  2008年   133509篇
  2007年   143344篇
  2006年   150924篇
  2005年   145150篇
  2004年   145944篇
  2003年   135799篇
  2002年   124406篇
  2001年   197234篇
  2000年   194195篇
  1999年   174289篇
  1998年   75858篇
  1997年   70573篇
  1996年   68758篇
  1995年   64336篇
  1994年   58172篇
  1993年   54001篇
  1992年   128558篇
  1991年   123372篇
  1990年   118820篇
  1989年   115363篇
  1988年   106256篇
  1987年   104311篇
  1986年   98409篇
  1985年   95819篇
  1984年   77781篇
  1983年   68453篇
  1982年   51624篇
  1981年   47707篇
  1980年   44728篇
  1979年   67686篇
  1978年   53043篇
  1977年   46606篇
  1976年   43239篇
  1975年   44061篇
  1974年   48991篇
  1973年   46928篇
  1972年   43927篇
  1971年   40618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