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   4382121篇
  免费   361881篇
  国内免费   15246篇
耳鼻咽喉   61734篇
儿科学   140823篇
妇产科学   114829篇
基础医学   666192篇
口腔科学   118647篇
临床医学   406195篇
内科学   798754篇
皮肤病学   111633篇
神经病学   373332篇
特种医学   171341篇
外国民族医学   753篇
外科学   669732篇
综合类   121228篇
现状与发展   92篇
一般理论   2614篇
预防医学   358903篇
眼科学   102355篇
药学   307425篇
  21篇
中国医学   11937篇
肿瘤学   220708篇
  2021年   57039篇
  2020年   38096篇
  2019年   59428篇
  2018年   77335篇
  2017年   59639篇
  2016年   66041篇
  2015年   78876篇
  2014年   115791篇
  2013年   181182篇
  2012年   126154篇
  2011年   130901篇
  2010年   130029篇
  2009年   133059篇
  2008年   117137篇
  2007年   123696篇
  2006年   133318篇
  2005年   126558篇
  2004年   127474篇
  2003年   117449篇
  2002年   106658篇
  2001年   168137篇
  2000年   162839篇
  1999年   149583篇
  1998年   73022篇
  1997年   68734篇
  1996年   66448篇
  1995年   61787篇
  1994年   55430篇
  1993年   51329篇
  1992年   106889篇
  1991年   101764篇
  1990年   97530篇
  1989年   95127篇
  1988年   87394篇
  1987年   85527篇
  1986年   80428篇
  1985年   78513篇
  1984年   65492篇
  1983年   58275篇
  1982年   47259篇
  1981年   43897篇
  1980年   41115篇
  1979年   55005篇
  1978年   44446篇
  1977年   39577篇
  1976年   36486篇
  1975年   36504篇
  1974年   39395篇
  1973年   37576篇
  1972年   35291篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
81.
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   
82.
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   
83.
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   
84.
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