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   4362829篇
  免费   350518篇
  国内免费   14708篇
耳鼻咽喉   60423篇
儿科学   139775篇
妇产科学   114536篇
基础医学   668558篇
口腔科学   118293篇
临床医学   399122篇
内科学   792799篇
皮肤病学   107883篇
神经病学   369548篇
特种医学   170032篇
外国民族医学   753篇
外科学   658162篇
综合类   121561篇
现状与发展   24篇
一般理论   2639篇
预防医学   362661篇
眼科学   101175篇
药学   308934篇
  26篇
中国医学   11950篇
肿瘤学   219201篇
  2021年   56323篇
  2020年   35923篇
  2019年   58969篇
  2018年   74567篇
  2017年   57171篇
  2016年   63288篇
  2015年   76289篇
  2014年   110560篇
  2013年   176193篇
  2012年   125434篇
  2011年   130278篇
  2010年   126368篇
  2009年   127990篇
  2008年   116358篇
  2007年   123764篇
  2006年   132508篇
  2005年   126569篇
  2004年   127838篇
  2003年   117978篇
  2002年   107151篇
  2001年   167124篇
  2000年   162199篇
  1999年   148880篇
  1998年   71808篇
  1997年   67688篇
  1996年   65706篇
  1995年   61098篇
  1994年   55033篇
  1993年   51080篇
  1992年   106720篇
  1991年   101520篇
  1990年   97360篇
  1989年   94905篇
  1988年   87243篇
  1987年   85433篇
  1986年   80298篇
  1985年   78467篇
  1984年   65469篇
  1983年   58270篇
  1982年   47226篇
  1981年   43886篇
  1980年   41096篇
  1979年   55152篇
  1978年   44802篇
  1977年   40021篇
  1976年   36885篇
  1975年   36844篇
  1974年   39636篇
  1973年   37802篇
  1972年   35399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