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   70476篇
  免费   6844篇
  国内免费   731篇
耳鼻咽喉   368篇
儿科学   1796篇
妇产科学   1109篇
基础医学   4589篇
口腔科学   1212篇
临床医学   9419篇
内科学   8160篇
皮肤病学   781篇
神经病学   2469篇
特种医学   1510篇
外国民族医学   1篇
外科学   8978篇
综合类   13043篇
现状与发展   1篇
一般理论   30篇
预防医学   13931篇
眼科学   474篇
药学   4096篇
  107篇
中国医学   4342篇
肿瘤学   1635篇
  2024年   312篇
  2023年   1469篇
  2022年   2223篇
  2021年   3132篇
  2020年   3119篇
  2019年   4909篇
  2018年   4351篇
  2017年   3281篇
  2016年   2295篇
  2015年   2254篇
  2014年   4466篇
  2013年   4753篇
  2012年   3979篇
  2011年   4213篇
  2010年   3335篇
  2009年   2915篇
  2008年   2818篇
  2007年   2563篇
  2006年   2348篇
  2005年   1603篇
  2004年   1281篇
  2003年   1156篇
  2002年   790篇
  2001年   692篇
  2000年   644篇
  1999年   483篇
  1998年   405篇
  1997年   371篇
  1996年   300篇
  1995年   251篇
  1994年   196篇
  1993年   125篇
  1992年   73篇
  1991年   68篇
  1990年   74篇
  1989年   46篇
  1988年   41篇
  1985年   870篇
  1984年   1399篇
  1983年   1117篇
  1982年   1106篇
  1981年   1108篇
  1980年   965篇
  1979年   849篇
  1978年   663篇
  1977年   467篇
  1976年   634篇
  1975年   555篇
  1974年   477篇
  1973年   431篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
National intercomparisons of activity measurements of 131I, a radioisotope widely used for diagnosis and therapy of thyroid related ailments, were initiated in 1979 as a quality assurance program, towards improving radiation safety procedures and related dosimetry in Nuclear Medicine Centres (NMCs) in India. Oral administration of a known quantity of radioiodine to patients requires accurate radioactivity measurements to be performed on a well-calibrated isotope calibrators. Under or over estimation of the activity due to a faulty or uncalibrated isotope calibrator could provide misleading results. Calibration of isotope calibrators and the traceablity of subsequent measurements to the national standards laboratory is one of the essential basic radiation safety requirement of the IAEA. In view of the stringent quality assurance requirements for activity measurements imposed by Atomic Energy Regulatory Board, a National Intercomparison Program was initiated and to date ten such intercomparison programs have been conducted by the Radiation Safety Systems Division, of the Bhabha Atomic Research Centre. This program has benefited the participants by making their measurements traceable to the National Primary Standards. Over the years there has been a marked increase in the number of NMCs participating in the intercomparison programs. As a result, the number of institution showing large deviation from the correct value has decreased considerably over the years. This program thus, has enabled participating NMCs to check their isotope calibrators so as to ensure proper delivery of radiation dose to the patients and hence to optimise patient exposure.  相似文献   
44.
刘瑾  杨青  王绵珍  兰亚佳 《现代预防医学》2003,30(5):689-693,696
基质金属蛋白酶(matrix metalloproteinases,MMPs)是一组锌离子依赖的蛋白水解酶,在ECM降解中起着重要作用。目前研究表明,MMPs活性异常不仅能促进肿瘤血管形成,还是人类多种肿瘤侵袭和转移的必要条件。本文就与肺癌侵袭和转移有关的MMPs研究作一综述。  相似文献   
45.
Objective: The scientific quality of research is an important ethical issue. To clarify the quality of research projects in pharmacotherapy/pharmacology, 40 randomly selected research projects in pharmacotherapy/pharmacology submitted to a research ethics committee were reviewed. Results: Eight of the projects would not have contributed new knowledge nor were they necessary as controls for the results of previous research. Fifteen of the research protocols were of good quality, 15 could be used after revisions, and 10 were unfit for use. Eleven of the research projects were not finished 5 years after they were started. A written report was produced from 26 of the projects. Nine were of good quality and could be accepted for publication in a medical journal, 10 of the reports were in need of revision before publication, and 7 should not be accepted for publication. Conclusion: Research in this field ought to be improved, and ways to improve the standard of clinical trials in pharmacotherapy are dicussed. Received: 1 April 1996 / Accepted in revised form: 28 June 1996  相似文献   
46.
医院管理不是孤立自存的现象,由于管理者和被管理都生活在一定的医院文化氛围之中,因此,医院文化的哲学内核是现代医院管理知识的精髓,医院组织的价值观念、道德准则和思维方式,深刻地影响和制约着现代医院管理的原则和方法,决定着现代医院管理的实施和成败。  相似文献   
47.
不断强化医务人员的服务意识是消除医患纠纷的首要条件,认真培养敬业精神是避免医患纠纷的根本途径;提高道德境界是避免医患纠纷的决定因素.  相似文献   
48.
49.
Abstract: Five typical mechanical heart valves (Starr-Edwards, Björk-Shiley convexo-concave (c-c), Björk-Shiley monostrut, Bicer-Val, and St. Jude Medical) were tested in the mitral position under the pulsatile flow condition. The test program included measurements of velocity and turbulent stresses at 5 downstream locations. The study was carried out using a sophisticated cardiac simulator in conjunction with a highly sensitive 2 component laser Doppler anemometer (LDA) system. The continuous monitoring of parametric time histories revealed useful details about the complex flow and helped to establish the locations and times of the peak parameter values. Based upon the nondimensional presentation of data, the following general conclusions can be made. First, all the 5 valve designs created elevated turbulent stresses during the accelerating and peak flow phases, presenting the possibility of thromboembolism and perhaps hemolysis. Second, the difference in valve configuration seemed to affect the flow characteristics; third, the bileaflet design of the St. Jude valve appeared to create a lower turbulence stress level.  相似文献   
50.
上海市闵行区流动人口中的孕产妇保健状况   总被引:3,自引:0,他引:3  
通过对上海市闵行区580名外来孕产妇及580名作为对照的本地孕产妇的孕产期保健现况调查分析,表明外来孕产妇缺乏必要的孕产期保健措施,有47.6%的外来孕产妇从未做产前检查,产后保健则完全没有,并由此而造成外来产妇在急产、死产、甚至孕产妇死亡等方面令人忧虑的现状。为适应和促进当前经济发展的新形势,改善流动人口的孕产妇保健状况,应对流动人口中孕产妇保健状况深入研究,并采取相应的措施。  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