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   2347414篇
  免费   175095篇
  国内免费   3326篇
耳鼻咽喉   32101篇
儿科学   75923篇
妇产科学   62694篇
基础医学   348285篇
口腔科学   63636篇
临床医学   211553篇
内科学   457557篇
皮肤病学   51733篇
神经病学   185359篇
特种医学   88025篇
外国民族医学   489篇
外科学   354045篇
综合类   47511篇
现状与发展   12篇
一般理论   849篇
预防医学   182758篇
眼科学   54327篇
药学   175151篇
  11篇
中国医学   4576篇
肿瘤学   129240篇
  2021年   19001篇
  2019年   19566篇
  2018年   27080篇
  2017年   20375篇
  2016年   22774篇
  2015年   25665篇
  2014年   36142篇
  2013年   54007篇
  2012年   74750篇
  2011年   79487篇
  2010年   47106篇
  2009年   44602篇
  2008年   74676篇
  2007年   79530篇
  2006年   80338篇
  2005年   77851篇
  2004年   74428篇
  2003年   71737篇
  2002年   69409篇
  2001年   108754篇
  2000年   111471篇
  1999年   93515篇
  1998年   27001篇
  1997年   23668篇
  1996年   24063篇
  1995年   22717篇
  1994年   20896篇
  1993年   19717篇
  1992年   72007篇
  1991年   70081篇
  1990年   68397篇
  1989年   65674篇
  1988年   60310篇
  1987年   59130篇
  1986年   55236篇
  1985年   53016篇
  1984年   39322篇
  1983年   33400篇
  1982年   19861篇
  1979年   35867篇
  1978年   25653篇
  1977年   21232篇
  1976年   20340篇
  1975年   21819篇
  1974年   26151篇
  1973年   24804篇
  1972年   23203篇
  1971年   22037篇
  1970年   20247篇
  1969年   19316篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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   
92.
93.
94.
95.
96.
97.
98.
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   
99.
100.
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   
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