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   514748篇
  免费   33757篇
  国内免费   3920篇
耳鼻咽喉   7176篇
儿科学   10566篇
妇产科学   12326篇
基础医学   74045篇
口腔科学   15183篇
临床医学   43318篇
内科学   103151篇
皮肤病学   12327篇
神经病学   39047篇
特种医学   21355篇
外国民族医学   83篇
外科学   78155篇
综合类   11097篇
现状与发展   4篇
一般理论   114篇
预防医学   25733篇
眼科学   12883篇
药学   43090篇
  3篇
中国医学   3569篇
肿瘤学   39200篇
  2021年   7123篇
  2020年   3842篇
  2019年   5811篇
  2018年   8274篇
  2017年   6468篇
  2016年   7475篇
  2015年   9523篇
  2014年   12209篇
  2013年   15302篇
  2012年   21730篇
  2011年   21636篇
  2010年   12636篇
  2009年   11445篇
  2008年   17534篇
  2007年   18136篇
  2006年   17378篇
  2005年   16103篇
  2004年   14808篇
  2003年   13842篇
  2002年   12921篇
  2001年   30419篇
  2000年   30745篇
  1999年   25355篇
  1998年   6187篇
  1997年   5038篇
  1996年   4467篇
  1995年   4105篇
  1994年   3640篇
  1993年   3314篇
  1992年   16936篇
  1991年   15761篇
  1990年   15031篇
  1989年   14685篇
  1988年   13294篇
  1987年   12727篇
  1986年   11706篇
  1985年   10961篇
  1984年   7437篇
  1983年   6012篇
  1982年   3034篇
  1979年   5892篇
  1978年   3683篇
  1977年   3267篇
  1975年   2914篇
  1974年   3391篇
  1973年   3137篇
  1972年   3103篇
  1971年   3008篇
  1970年   2713篇
  1969年   2736篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
Digestive Diseases and Sciences - To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be...  相似文献   
122.
<正>Photobiomodulation (PBM)-the irradiation of cells or tissues with low-intensity red to near-infrared light-is emerging as an effective means of enhancing cell and tissue resilience and repair. As reviewed elsewhere (Gordon et al., 2019), the intracellular effects of  相似文献   
123.
Objective: This study investigated the effect of regular swimming exercise according to the duration-intensity on neurocognitive function in a cerebral infarction rat model.

Methods: Forty male Sprague–Dawley 10-week-old rats, weighing 300 ± 50 g, were subjected to photothrombotic cerebral infarction. The remaining 36 rats were randomly divided into four groups (n = 9 per group: non-exercise (group A); swimming exercise of short duration-intensity (5 min/day, group B); swimming exercise of moderate duration-intensity (10 min/day, group C); and swimming exercise of long duration-intensity (20 min/day, group D). Exercise was performed five times a week for 4 weeks, beginning the day after cerebral infarction. Neurocognitive function was evaluated with the Morris water maze test. Immunohistochemistry and western blot analysis examined brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) at 4 weeks postinfarction.

Results: At 4 weeks postinfarction, escape latency was found to be shorter in group C than in any of groups A, B, or D. Immunohistochemistry revealed the most significant immunoreactivity for BDNF and VEGF in group C. Western blot analysis demonstrated that BDNF and VEGF proteins were markedly expressed in group C.

Conclusions: Regular swimming exercise of moderate duration-intensity may be the most effective exercise protocol for the recovery of neurocognitive function in cerebral infarction rat model.  相似文献   

124.
Young children enter kindergarten with varying levels of readiness and abilities to learn. One factor that contributes to lower levels of school readiness is poverty. One timely, cost-effective, and feasible strategy to boost school readiness, regardless of exposure to high-quality preschool is to leverage the summer months prior to kindergarten entry and provide comprehensive, evidence-based programming immediately before the school year begins. The current study implemented a community-based summer programme targeted at improving school readiness for 25 four- and five-year-old children in a low-income community. Across the 9-week study, children participated in two types of early literacy activities and the Incredible Years social/emotional learning curriculum. Results indicate that participants demonstrated significant growth across three early literacy skills and were rated as overall stable regarding their behaviour across the summer. These results are discussed along with implications and future directions in this line of research.  相似文献   
125.
126.
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   
127.
128.
129.
International Journal of Legal Medicine - Sex identification is a primary step in forensic analysis of skeletal remains. The accuracy of sex estimation methods greatly depends on the sexual...  相似文献   
130.
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