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   2352255篇
  免费   171384篇
  国内免费   3333篇
耳鼻咽喉   32103篇
儿科学   75949篇
妇产科学   62728篇
基础医学   348451篇
口腔科学   63704篇
临床医学   211538篇
内科学   457730篇
皮肤病学   51816篇
神经病学   185435篇
特种医学   88054篇
外国民族医学   489篇
外科学   354156篇
综合类   47515篇
现状与发展   12篇
一般理论   848篇
预防医学   182896篇
眼科学   54357篇
药学   175213篇
  11篇
中国医学   4580篇
肿瘤学   129387篇
  2021年   19044篇
  2019年   19619篇
  2018年   27138篇
  2017年   20412篇
  2016年   22794篇
  2015年   25698篇
  2014年   36171篇
  2013年   54054篇
  2012年   74814篇
  2011年   79549篇
  2010年   47160篇
  2009年   44650篇
  2008年   74739篇
  2007年   79588篇
  2006年   80408篇
  2005年   77910篇
  2004年   74448篇
  2003年   71774篇
  2002年   69459篇
  2001年   108790篇
  2000年   111500篇
  1999年   93538篇
  1998年   27014篇
  1997年   23672篇
  1996年   24073篇
  1995年   22722篇
  1994年   20896篇
  1993年   19719篇
  1992年   72014篇
  1991年   70089篇
  1990年   68414篇
  1989年   65679篇
  1988年   60314篇
  1987年   59138篇
  1986年   55228篇
  1985年   53013篇
  1984年   39317篇
  1983年   33401篇
  1982年   19860篇
  1979年   35872篇
  1978年   25652篇
  1977年   21232篇
  1976年   20333篇
  1975年   21818篇
  1974年   26148篇
  1973年   24807篇
  1972年   23210篇
  1971年   22039篇
  1970年   20248篇
  1969年   19315篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
BackgroundSecond-hand smoking or environmental tobacco smoke is a critical health risk. Children are the most vulnerable to second-hand smoking because of their small bronchial ducts, less developed immunity, and low-physical activity.ObjectivesThe purpose of this study was to ascertain the effects of second-hand smoking on lung functions in athlete and non-athlete school-aged children.MethodsThis observational study included forty-six school-aged children, their age was 8–15 years, assigned to three groups; 2 study groups and 1 control group (n=15). The study groups comprised of 16 football players, and of 15 cyclists. Lung functions were evaluated recording forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow using digital spirometer.ResultsAll measures were recorded in definite values and the children were also classified into second-hand smoking (SH), or non-exposed to tobacco smoking (NE). The findings presented a significant increase (p<0.05) of the study groups in forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow solely for the non-exposed children. However, there were non-significant differences between the cyclists and football players or between the passive smoking children and non-exposed children in any of the two study groups (p>0.05).ConclusionThe outcomes of this study suggest beneficial influences of the sports activity on the lung functions, without different influences of the cyclists and football players on the lung functions.  相似文献   
43.
44.
45.
46.
47.
The present study aimed at measuring seropositivities for infection by Ascaris suum and Toxocara canis using the excretory/secretory (E/S) antigens from Ascaris suum (AES) and Toxocara canis (TES) within an indigenous population. In addition, quantification of cytokine expressions in peripheral blood cells was determined. A total of 50 Warao indigenous were included; of which 43 were adults and seven children. In adults, 44.1% were seropositive for both parasites; whereas children had only seropositivity to one or the other helminth. For ascariosis, the percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%, respectively. While that for toxocariosis, the percentage of TES seropositivity in adults and children was low; 9.3% and 14.3%, respectively. The percentage of seronegativity was comparable for AES and TES antigens in adults (27.9%) and children (28.6%). When positive sera were analyzed by Western blotting technique using AES antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9, 98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that Blastocystis hominis, Hymenolepis nana and Entamoeba coli were the most commonly observed intestinal parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and IL-4 expressions showed that there was only a significant increased expression of IL-4 in indigenous with TES seropositivity (p < 0.002). Ascaris and Toxocara seropositivity was prevalent among Warao indigenous.  相似文献   
48.
A 42‐year‐old man presented with a viral prodrome and tested positive for influenza A. He rapidly deteriorated developing cardiogenic shock, rhabdomyolysis, and acute kidney injury. Patient improved 1 week later with supportive measures including vasopressors, inotropes, and an intraaortic balloon pump. We report this case as it highlights the discordance between echocardiographic ventricular wall thickening as a result of myocardial edema, and electrocardiographic findings at presentation, with a reversal in findings at time of resolution. Additionally, there was some suggestion of a regional pattern to the reduced longitudinal strain.  相似文献   
49.
50.
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