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   2509197篇
  免费   194145篇
  国内免费   10125篇
耳鼻咽喉   32091篇
儿科学   81100篇
妇产科学   67294篇
基础医学   354854篇
口腔科学   68651篇
临床医学   237122篇
内科学   497778篇
皮肤病学   55185篇
神经病学   209571篇
特种医学   97513篇
外国民族医学   635篇
外科学   370507篇
综合类   56729篇
现状与发展   3篇
一般理论   934篇
预防医学   209220篇
眼科学   54471篇
药学   179683篇
  11篇
中国医学   5107篇
肿瘤学   135008篇
  2021年   20147篇
  2019年   20902篇
  2018年   29138篇
  2017年   22487篇
  2016年   25682篇
  2015年   29023篇
  2014年   40368篇
  2013年   61146篇
  2012年   79917篇
  2011年   85455篇
  2010年   51356篇
  2009年   48878篇
  2008年   78619篇
  2007年   83365篇
  2006年   84485篇
  2005年   81949篇
  2004年   77823篇
  2003年   74672篇
  2002年   71579篇
  2001年   110895篇
  2000年   113758篇
  1999年   95934篇
  1998年   29591篇
  1997年   26475篇
  1996年   26903篇
  1995年   26385篇
  1994年   24693篇
  1993年   23132篇
  1992年   78116篇
  1991年   76182篇
  1990年   73478篇
  1989年   69793篇
  1988年   64853篇
  1987年   63557篇
  1986年   60383篇
  1985年   58068篇
  1984年   44425篇
  1983年   37467篇
  1982年   23518篇
  1981年   21049篇
  1979年   40076篇
  1978年   29150篇
  1977年   24203篇
  1976年   23048篇
  1975年   23741篇
  1974年   28437篇
  1973年   27461篇
  1972年   25379篇
  1971年   23438篇
  1970年   21577篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Levels of the soluble form of the triggering receptor expressed on myeloid cells (sTREM)-1 are elevated in severe sepsis. However, it is not known whether sTREM-1 measurements can distinguish milder bacterial infections from noninfectious inflammation. The present authors studied whether serum sTREM-1 levels differ in community-acquired pneumonia, exacerbations of chronic obstructive pulmonary disease (COPD), asthma and controls, and whether sTREM-1 may be used as a surrogate marker for the need for antibiotics. Serum sTREM-1 levels in 150 patients with pneumonia, COPD and asthma exacerbations and 62 healthy controls were measured. Serum sTREM-1 levels were significantly elevated in pneumonia (median 295.2 ng x mL(-1)), COPD (280.3 ng x mL(-1)) and asthma exacerbations (184.0 ng x mL(-1)) compared with controls (83.1 ng x mL(-1)). Levels were higher in pneumonia and Anthonisen type 1 COPD exacerbations than in type 2 and 3 COPD and asthma exacerbations. The area under the receiver operating characteristics curve for sTREM-1 as a surrogate marker for the need for antibiotics was 0.77. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 were elevated predominantly in pneumonia and Anthonisen type 1 COPD exacerbations versus type 2 and 3 chronic obstructive pulmonary disease exacerbations, asthma and controls. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 has moderate but insufficient accuracy as a surrogate marker for the need for antibiotics in lower respiratory tract infections.  相似文献   
52.
53.
54.
55.
56.
Imaging     
  相似文献   
57.
58.
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   
59.
ABSTRACT: Background: Although increases in perinatal mortality risk associated with fetal macrosomia are well documented, the optimal route of delivery for fetuses with suspected macrosomia remains controversial. The objective of this investigation was to assess the risk of neonatal death among macrosomic infants delivered vaginally compared with those delivered by cesarean section. Methods: Data were derived from the U.S. 1995–1999 Linked Live Birth‐Infant Death Cohort files and term (37–44 wk), single live births to United States resident mothers selected. A proportional hazards model was used to analyze the risk of neonatal death associated with cesarean delivery among 3 categories of macrosomic infants (infants weighing 4,000–4,499 g; 4,500–4,999 g; and 5,000+ g). Results: After controlling for maternal characteristics and complications, the adjusted hazard ratio for neonatal death associated with cesarean delivery among the 3 categories of macrosomic infants was 1.40, 1.30, and 0.85. Conclusions: Although cesarean delivery may reduce the risk of death for the heaviest infants (5,000+ g), the relative benefit of this intervention for macrosomic infants weighing 4,000–4,999 g remains debatable. Thus, policies in support of prophylactic cesarean delivery for suspected fetal macrosomia may need to be reevaluated. (BIRTH 33:4 December 2006)  相似文献   
60.
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