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   1645033篇
  免费   134532篇
  国内免费   2964篇
耳鼻咽喉   22409篇
儿科学   53744篇
妇产科学   46990篇
基础医学   234564篇
口腔科学   47837篇
临床医学   145057篇
内科学   323269篇
皮肤病学   35599篇
神经病学   133818篇
特种医学   67157篇
外国民族医学   474篇
外科学   248742篇
综合类   40109篇
现状与发展   4篇
一般理论   558篇
预防医学   125500篇
眼科学   37691篇
药学   125023篇
  3篇
中国医学   3389篇
肿瘤学   90592篇
  2018年   15978篇
  2016年   14301篇
  2015年   16841篇
  2014年   22797篇
  2013年   33863篇
  2012年   46098篇
  2011年   48211篇
  2010年   28454篇
  2009年   27036篇
  2008年   45433篇
  2007年   47646篇
  2006年   48201篇
  2005年   46697篇
  2004年   45772篇
  2003年   43665篇
  2002年   42639篇
  2001年   76302篇
  2000年   78889篇
  1999年   66906篇
  1998年   18032篇
  1997年   16594篇
  1996年   16524篇
  1995年   16230篇
  1994年   15234篇
  1993年   14405篇
  1992年   55791篇
  1991年   54144篇
  1990年   52859篇
  1989年   51171篇
  1988年   47517篇
  1987年   46867篇
  1986年   44535篇
  1985年   43112篇
  1984年   32249篇
  1983年   27756篇
  1982年   16304篇
  1981年   14582篇
  1980年   13692篇
  1979年   30621篇
  1978年   21211篇
  1977年   17883篇
  1976年   16786篇
  1975年   17666篇
  1974年   21606篇
  1973年   20804篇
  1972年   18967篇
  1971年   17839篇
  1970年   16381篇
  1969年   15363篇
  1968年   14034篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Bone mineral density (BMD) is a highly heritable predictor of osteoporotic fracture. GWAS have identified hundreds of loci influencing BMD, but few have been functionally analyzed. In this study, we show that SNPs within a BMD locus on chromosome 14q32.32 alter splicing and expression of PAR-1a/microtubule affinity regulating kinase 3 (MARK3), a conserved serine/threonine kinase known to regulate bioenergetics, cell division, and polarity. Mice lacking Mark3 either globally or selectively in osteoblasts have increased bone mass at maturity. RNA profiling from Mark3-deficient osteoblasts suggested changes in the expression of components of the Notch signaling pathway. Mark3-deficient osteoblasts exhibited greater matrix mineralization compared with controls that was accompanied by reduced Jag1/Hes1 expression and diminished downstream JNK signaling. Overexpression of Jag1 in Mark3-deficient osteoblasts both in vitro and in vivo normalized mineralization capacity and bone mass, respectively. Together, these findings reveal a mechanism whereby genetically regulated alterations in Mark3 expression perturb cell signaling in osteoblasts to influence bone mass.  相似文献   
2.
3.
4.
5.
6.
7.
8.
Moderate sedatives have been increasingly used to improve patient comfort during flexible bronchoscopy (FB). However, routine use of moderate sedation during FB is controversial because its efficacy and safety are not well established.This study aims to evaluate the efficacy and safety of moderate sedation during FB.A search was made of Medline, EMBASE, and the Cochrane Library to May 2014.Randomized controlled trials (RCTs) and quasi-RCTs were included.The main analysis was designed to examine the efficacy of moderate sedation during FB in sedation than no-sedation.The willingness to repeat FB was significantly more in sedation than no-sedation (odds ratio [OR] 2.30; 95% confidence interval [CI] 1.11–4.73; P = 0.02; I2 = 22.5). The duration of FB was shorter in sedation group than no-sedation group (standardized mean difference [SMD] −0.21; 95% CI −0.38 to −0.03; P = 0.02; I2 = 78.3%). Event of hypoxia was not significantly different between sedation and no-sedation groups (OR 0.86; 95% CI 0.42–1.73; P = 0.67; I2 = 0%). The SpO2 during procedure was not different between sedation and no-sedation groups (SMD −0.14; 95% CI −0.37 to 0.08; P = 0.21; I2 = 49.9%). However, in subgroup analysis without supplemental oxygen, the SpO2 was significantly lower in sedation than no-sedation group (SMD −0.45; 95% CI −0.78 to −0.11; P = 0.01; I2 = 0.0%).According to this meta-analysis, moderate sedation in FB would be useful in patients who will require repeated bronchoscopies as well as safe in respiratory depression. To our knowledge, although the various sedative drugs are already used in the real field, this analysis was the first attempt to quantify objective results. We anticipate more definite and studies designed to elucidate standardized outcomes for moderate sedation in FB.  相似文献   
9.
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.  相似文献   
10.
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