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   2162461篇
  免费   151296篇
  国内免费   2846篇
耳鼻咽喉   29505篇
儿科学   70370篇
妇产科学   59061篇
基础医学   314903篇
口腔科学   60371篇
临床医学   197372篇
内科学   414252篇
皮肤病学   47892篇
神经病学   169160篇
特种医学   82242篇
外国民族医学   461篇
外科学   315849篇
综合类   44630篇
现状与发展   3篇
一般理论   781篇
预防医学   167088篇
眼科学   49359篇
药学   165375篇
  12篇
中国医学   4524篇
肿瘤学   123393篇
  2018年   22620篇
  2017年   17510篇
  2016年   19495篇
  2015年   22157篇
  2014年   30638篇
  2013年   45959篇
  2012年   62707篇
  2011年   66579篇
  2010年   38991篇
  2009年   37141篇
  2008年   62597篇
  2007年   66962篇
  2006年   67234篇
  2005年   64982篇
  2004年   62351篇
  2003年   59931篇
  2002年   57947篇
  2001年   104437篇
  2000年   106844篇
  1999年   89672篇
  1998年   23944篇
  1997年   21465篇
  1996年   21658篇
  1995年   20351篇
  1994年   18845篇
  1993年   17701篇
  1992年   69539篇
  1991年   67588篇
  1990年   66038篇
  1989年   63843篇
  1988年   58459篇
  1987年   57044篇
  1986年   54199篇
  1985年   51053篇
  1984年   38058篇
  1983年   32748篇
  1982年   18785篇
  1981年   16725篇
  1979年   35319篇
  1978年   24970篇
  1977年   21554篇
  1976年   19450篇
  1975年   21437篇
  1974年   25623篇
  1973年   25011篇
  1972年   23820篇
  1971年   22298篇
  1970年   20827篇
  1969年   19870篇
  1968年   18170篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients.  相似文献   
46.
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006)  相似文献   
47.
48.
49.
50.
OBJECTIVE: To establish reference intervals for the fetal right, left and total lung volumes and heart volume between 12 and 32 weeks of gestation. METHODS: Fetal lung and heart volumes were measured using three-dimensional (3D) ultrasound in 650 normal singleton pregnancies at 12-32 weeks. The VOCAL (Virtual Organ Computer-aided AnaLysis) technique was used to obtain a sequence of six sections of each lung and the heart around a fixed axis, each after a 30 degrees rotation from the previous one. The rotation axis for the lungs extended from the apex to the upper limit of the diaphragm dome, and the rotation axis for the heart extended from its apex to its connection to the great vessels. The contour of each of these organs was drawn manually in the six different rotation planes to obtain the 3D volume measurement. In 60 cases the fetal lungs and heart volumes were measured by the same sonographer twice and also by a second sonographer once in order to compare the measurements and calculate intra- and interobserver agreement. RESULTS: The total lung volume and heart volume increased with gestation, from respective mean values of 1.6 and 0.6 mL at 12 weeks to 10.9 and 4.3 mL at 20 weeks and 49.3 and 26.6 mL at 32 weeks. The right to left lung volume ratio did not change significantly with gestation (median, 0.7), whereas the heart to total lung volume ratio increased with gestation from about 0.3 at 12 weeks to 0.5 at 32 weeks. In the Bland-Altman plot, the difference between paired measurements by two sonographers was, in 95% of the cases, less than 0.05, 0.5 and 1.9 mL for each lung at 12-13, 19-22 and 29-32 weeks, respectively, and the corresponding values for the heart volumes were 0.04, 0.4 and 2.3 mL. CONCLUSIONS: In normal fetuses the lung and heart volumes increase between 12 and 32 weeks of gestation. The extent to which in pathological pregnancies possible deviations in these measurements from normal prove to be useful in the prediction of outcome remains to be determined.  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