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   4588840篇
  免费   362143篇
  国内免费   14933篇
耳鼻咽喉   64096篇
儿科学   147682篇
妇产科学   121457篇
基础医学   697900篇
口腔科学   126007篇
临床医学   420756篇
内科学   832853篇
皮肤病学   112675篇
神经病学   383768篇
特种医学   178214篇
外国民族医学   795篇
外科学   692418篇
综合类   126136篇
现状与发展   24篇
一般理论   2689篇
预防医学   381837篇
眼科学   107889篇
药学   325686篇
  26篇
中国医学   12509篇
肿瘤学   230499篇
  2021年   56395篇
  2019年   59022篇
  2018年   75074篇
  2017年   57547篇
  2016年   63719篇
  2015年   76498篇
  2014年   110815篇
  2013年   176468篇
  2012年   129630篇
  2011年   135972篇
  2010年   127929篇
  2009年   128832篇
  2008年   122023篇
  2007年   130432篇
  2006年   138643篇
  2005年   132780篇
  2004年   134005篇
  2003年   123956篇
  2002年   113342篇
  2001年   177905篇
  2000年   173675篇
  1999年   157927篇
  1998年   73192篇
  1997年   68508篇
  1996年   66559篇
  1995年   61902篇
  1994年   55882篇
  1993年   51780篇
  1992年   114253篇
  1991年   109663篇
  1990年   105695篇
  1989年   103080篇
  1988年   94770篇
  1987年   93016篇
  1986年   87425篇
  1985年   85423篇
  1984年   70336篇
  1983年   62228篇
  1982年   48784篇
  1981年   45273篇
  1980年   42466篇
  1979年   60483篇
  1978年   48320篇
  1977年   42948篇
  1976年   39726篇
  1975年   40549篇
  1974年   44355篇
  1973年   42194篇
  1972年   39759篇
  1971年   36891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