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   1306073篇
  免费   94804篇
  国内免费   2402篇
耳鼻咽喉   18465篇
儿科学   43112篇
妇产科学   38295篇
基础医学   191197篇
口腔科学   35845篇
临床医学   110890篇
内科学   257543篇
皮肤病学   27142篇
神经病学   101377篇
特种医学   51104篇
外国民族医学   379篇
外科学   201201篇
综合类   27767篇
现状与发展   2篇
一般理论   302篇
预防医学   94972篇
眼科学   29646篇
药学   99950篇
  7篇
中国医学   3103篇
肿瘤学   70980篇
  2018年   12727篇
  2016年   10697篇
  2015年   12437篇
  2014年   17046篇
  2013年   25700篇
  2012年   35464篇
  2011年   37892篇
  2010年   22418篇
  2009年   21029篇
  2008年   36382篇
  2007年   39386篇
  2006年   39897篇
  2005年   39091篇
  2004年   37511篇
  2003年   36473篇
  2002年   35926篇
  2001年   58941篇
  2000年   60409篇
  1999年   51460篇
  1998年   14543篇
  1997年   13066篇
  1996年   13283篇
  1995年   12526篇
  1994年   11933篇
  1993年   11007篇
  1992年   41388篇
  1991年   40745篇
  1990年   40241篇
  1989年   39044篇
  1988年   36459篇
  1987年   35624篇
  1986年   34020篇
  1985年   32410篇
  1984年   24116篇
  1983年   20959篇
  1982年   12464篇
  1981年   11001篇
  1979年   22790篇
  1978年   15971篇
  1977年   13812篇
  1976年   13049篇
  1975年   14278篇
  1974年   16791篇
  1973年   16153篇
  1972年   15416篇
  1971年   14292篇
  1970年   13291篇
  1969年   12803篇
  1968年   12054篇
  1967年   10547篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
BackgroundHepatopancreatobiliary (HPB) surgery fellowship training has multiple paths. Prospective trainees and employers must understand the differences between training pathways. This study examines self-reported fellowship experiences and current scope of practice across three pathways.MethodsAn online survey was disseminated to 654 surgeons. These included active Americas Hepato-Pancreato-Biliary Association (AHPBA) members and recent graduates of HPB, transplant–HPB and HPB–heavy surgical oncology fellowships.ResultsA total of 416 (64%) surgeons responded. Most respondents were male (89%) and most were practising in an academic setting (83%). 290 (70%) respondents underwent formal fellowship training. Although fellowship experiences varied, current practice was largely similar. Minimally invasive surgery (MIS) and ultrasound were the most commonly identified areas of training deficiencies and were, respectively, cited as such by 47% and 34% of HPB-, 49% and 50% of transplant-, and 52% and 25% of surgical oncology-trained respondents. Non-HPB cases performed in current practice included gastrointestinal (GI) and general surgery cases (56% and 49%, respectively) for HPB-trained respondents, transplant and general surgery cases (87% and 21%, respectively) for transplant-trained respondents, and GI surgery and non-HPB surgical oncology cases (70% and 28%, respectively) for surgical oncology-trained respondents.ConclusionsFellowship training in HPB surgery varies by training pathway. Training in MIS and ultrasound is deficient in each pathway. The ultimate scope of non-transplant HPB practice appears similar across training pathways. Thus, training pathway choice is best guided by the training experience desired and non-HPB components of anticipated practice.  相似文献   
92.
93.
Abstract

This study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos.  相似文献   
94.
95.
96.
97.
ABSTRACT

Purpose

To investigate the effect of 1% tropicamide on anterior chamber aqueous flare (ACAF) measurements acquired with laser flare meter in patients with pseudoexfoliation.  相似文献   
98.
99.
Novel coronavirus, SARS-CoV2, has caused pandemic of highly contagious disease called coronavirus disease 2019 (COVID-19), with epicenters in China, Italy,  相似文献   
100.
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