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   1405066篇
  免费   118295篇
  国内免费   6523篇
耳鼻咽喉   17620篇
儿科学   44449篇
妇产科学   38009篇
基础医学   193411篇
口腔科学   38878篇
临床医学   125813篇
内科学   293974篇
皮肤病学   33673篇
神经病学   116520篇
特种医学   58291篇
外国民族医学   274篇
外科学   219481篇
综合类   31829篇
现状与发展   2篇
一般理论   438篇
预防医学   112492篇
眼科学   29288篇
药学   98642篇
  5篇
中国医学   2519篇
肿瘤学   74276篇
  2018年   15435篇
  2017年   11881篇
  2016年   14128篇
  2015年   16233篇
  2014年   22017篇
  2013年   32805篇
  2012年   42176篇
  2011年   44964篇
  2010年   27171篇
  2009年   25791篇
  2008年   41404篇
  2007年   44142篇
  2006年   45417篇
  2005年   43550篇
  2004年   41278篇
  2003年   39978篇
  2002年   37791篇
  2001年   67432篇
  2000年   69778篇
  1999年   57508篇
  1998年   16941篇
  1997年   15181篇
  1996年   16158篇
  1995年   16379篇
  1994年   15210篇
  1993年   14255篇
  1992年   47217篇
  1991年   45857篇
  1990年   44048篇
  1989年   41894篇
  1988年   38827篇
  1987年   38140篇
  1986年   35930篇
  1985年   34731篇
  1984年   26447篇
  1983年   22171篇
  1982年   13930篇
  1981年   12525篇
  1980年   11803篇
  1979年   23596篇
  1978年   17133篇
  1977年   14430篇
  1976年   13227篇
  1975年   13764篇
  1974年   16140篇
  1973年   15435篇
  1972年   14188篇
  1971年   13064篇
  1970年   11902篇
  1969年   11122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
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   
16.
17.
Maternal and Child Health Journal - Early life exposures can have an impact on a child’s developmental trajectory and children born late preterm (34–36 weeks gestational age)...  相似文献   
18.
19.
20.
Monitoring variations in the functioning of the autonomic nervous system may help personalize training of runners and provide more pronounced physiological adaptations and performance improvements. We systematically reviewed the scientific literature comparing physiological adaptations and/or improvements in performance following training based on responses of the autonomic nervous system (ie, changes in heart rate variability) and predefined training. PubMed, SPORTDiscus, and Web of Science were searched systematically in July 2019. Keywords related to endurance, running, autonomic nervous system, and training. Studies were included if they (a) involved interventions consisting predominantly of running training; (b) lasted at least 3 weeks; (c) reported pre- and post-intervention assessment of running performance and/or physiological parameters; (d) included an experimental group performing training adjusted continuously on the basis of alterations in HRV and a control group; and (e) involved healthy runners. Five studies involving six interventions and 166 participants fulfilled our inclusion criteria. Four HRV-based interventions reduced the amount of moderate- and/or high-intensity training significantly. In five interventions, improvements in performance parameters (3000 m, 5000 m, Loadmax, Tlim) were more pronounced following HRV-based training. Peak oxygen uptake () and submaximal running parameters (eg, LT1, LT2) improved following both HRV-based and predefined training, with no clear difference in the extent of improvement in . Submaximal running parameters tended to improve more following HRV-based training. Research findings to date have been limited and inconsistent. Both HRV-based and predefined training improve running performance and certain submaximal physiological adaptations, with effects of the former training tending to be greater.  相似文献   
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