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   4368451篇
  免费   350941篇
  国内免费   14704篇
耳鼻咽喉   60536篇
儿科学   140044篇
妇产科学   114706篇
基础医学   669128篇
口腔科学   118637篇
临床医学   399551篇
内科学   794154篇
皮肤病学   108022篇
神经病学   370401篇
特种医学   170395篇
外国民族医学   756篇
外科学   658888篇
综合类   121669篇
现状与发展   24篇
一般理论   2634篇
预防医学   362601篇
眼科学   101417篇
药学   309013篇
  27篇
中国医学   11961篇
肿瘤学   219532篇
  2021年   56216篇
  2020年   35851篇
  2019年   58863篇
  2018年   74484篇
  2017年   57088篇
  2016年   63202篇
  2015年   76122篇
  2014年   110364篇
  2013年   175982篇
  2012年   125230篇
  2011年   130123篇
  2010年   126180篇
  2009年   127824篇
  2008年   116238篇
  2007年   123714篇
  2006年   132426篇
  2005年   126411篇
  2004年   127779篇
  2003年   117876篇
  2002年   107148篇
  2001年   167557篇
  2000年   162682篇
  1999年   149220篇
  1998年   71791篇
  1997年   67713篇
  1996年   65743篇
  1995年   61159篇
  1994年   55069篇
  1993年   51104篇
  1992年   107176篇
  1991年   101928篇
  1990年   97800篇
  1989年   95372篇
  1988年   87578篇
  1987年   85842篇
  1986年   80704篇
  1985年   78872篇
  1984年   65728篇
  1983年   58485篇
  1982年   47329篇
  1981年   43982篇
  1980年   41196篇
  1979年   55492篇
  1978年   45030篇
  1977年   40193篇
  1976年   37078篇
  1975年   37008篇
  1974年   39897篇
  1973年   38027篇
  1972年   35596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