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   50583篇
  免费   5000篇
  国内免费   3763篇
耳鼻咽喉   321篇
儿科学   463篇
妇产科学   506篇
基础医学   5923篇
口腔科学   799篇
临床医学   7348篇
内科学   7771篇
皮肤病学   640篇
神经病学   2712篇
特种医学   2034篇
外国民族医学   24篇
外科学   4572篇
综合类   8325篇
现状与发展   15篇
一般理论   7篇
预防医学   3137篇
眼科学   1524篇
药学   5417篇
  96篇
中国医学   3175篇
肿瘤学   4537篇
  2024年   238篇
  2023年   1000篇
  2022年   2469篇
  2021年   3026篇
  2020年   2250篇
  2019年   1826篇
  2018年   1960篇
  2017年   1735篇
  2016年   1598篇
  2015年   2374篇
  2014年   2848篇
  2013年   2491篇
  2012年   3631篇
  2011年   4038篇
  2010年   2448篇
  2009年   1915篇
  2008年   2547篇
  2007年   2598篇
  2006年   2549篇
  2005年   2601篇
  2004年   1507篇
  2003年   1350篇
  2002年   1129篇
  2001年   1110篇
  2000年   1165篇
  1999年   1224篇
  1998年   794篇
  1997年   812篇
  1996年   631篇
  1995年   577篇
  1994年   526篇
  1993年   303篇
  1992年   382篇
  1991年   312篇
  1990年   285篇
  1989年   245篇
  1988年   231篇
  1987年   210篇
  1986年   156篇
  1985年   110篇
  1984年   50篇
  1983年   38篇
  1982年   19篇
  1981年   12篇
  1980年   13篇
  1979年   12篇
  1966年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.  相似文献   
2.
3.
4.
5.
6.
7.
This meta-analysis examined whether early decompressive craniectomy (DC) can improve control of intracranial pressure (ICP) and mortality in patients with traumatic brain injury (TBI).Medline, Cochrane, EMBASE, and Google Scholar databases were searched until May 14, 2015, using the following terms: traumatic brain injury, refractory intracranial hypertension, high intracranial pressure, craniectomy, standard care, and medical management. Randomized controlled trials in which patients with TBI received DC and non-DC medical treatments were included.Of the 84 articles identified, 8 studies were selected for review, with 3 randomized controlled trials s having a total of 256 patients (123 DCs, 133 non-DCs) included in the meta-analysis. Patients receiving DC had a significantly greater reduction of ICP and shorter hospital stay. They also seemed to have lower odds of death than patients receiving only medical management, but the P value did not reach significance (pooled odds ratio 0.531, 95% confidence interval 0.209–1.350, Z = 1.95, P = 0.183) with respect to the effect on overall mortality; a separate analysis of 3 retrospective studies yielded a similar result.Whereas DC might effectively reduce ICP and shorten hospital stay in patients with TBI, its effect in decreasing mortality has not reached statistical significance.  相似文献   
8.
不同强度运动对大鼠心脏降钙素基因相关肽的影响   总被引:5,自引:0,他引:5  
目的:探讨不同强度运动训练对降钙素基因相关肽(CGRP)在心脏组织中表达的影响及其作用机制。方法:将60只SD大鼠随机分为对照组(C组)、小强度运动组(LE组)、中等强度运动组(ME组)和大强度运动组(HE组),每组15只。建立8周不同强度运动训练动物模型,采用免疫组织化学法和计算机图像分析技术,对大鼠心脏形态结构进行观察,并进行心脏CGRP免疫组化分析。结果:8周小强度运动后,大鼠心脏CGRP表达较对照组变化不明显;8周中等强度运动后,大鼠心脏CGRP表达较对照组显著增加(P<0.05),HE染色、HBFP染色和变色酸2R亮绿染色显示心肌组织形态结构无明显改变,仅心肌纤维有轻度缺血缺氧改变;8周大强度运动后,大鼠心脏CGRP表达较对照组显著减少(P<0.05),HE染色、HBFP染色和变色酸2R亮绿染色显示心肌形态结构发生改变并存在明显的缺血缺氧损伤。结果表明,长期中等强度运动使心脏CGRP表达增加,改善了冠状循环和心肌血液供应,对心肌细胞具有保护作用;长期大强度运动使心脏CGRP对心肌细胞的保护作用减弱,可能是导致心肌发生缺血缺氧性损伤的重要原因之一。  相似文献   
9.
BACKGROUND: The validity of parent reports regarding children's attention-deficit/hyperactivity disorder (ADHD) symptoms has been questioned. This study assessed whether parent reports were as sensitive as teacher reports to document change in ADHD symptoms during clinical trials with atomoxetine. METHODS: Data were compared from two randomized, double-blind, placebo-controlled clinical trials of atomoxetine using different versions (parent or teacher) of the same rating scale (Attention-Deficit/Hyperactivity Disorder Rating Scale-IV [parent or teacher] Version: Investigator Administered and Scored - ADHD RS). Exclusion criteria included history of bipolar disorder, psychosis, seizures, alcohol abuse, or positive drug screen. Patients (6-16 years old) were treated with atomoxetine (titrated to a maximum dose of 1.8 mg/kg/day) administered once daily for up to 7 weeks. Parent and teacher ratings were compared using an analysis of covariance (ANCOVA) model. RESULTS: The analysis (n = 318) showed that treatment effects (mean change, baseline to endpoint) were similar between parent and teacher ratings (total, p = .762; inattention, p = .519; hyperactive/impulsive, p = .955). Effect sizes also were similar based on total scores (parent ratings = .69; teacher ratings = .63). CONCLUSIONS: Parent reports are as sensitive as teacher reports in assessing the efficacy of long-acting pharmacologic treatment for ADHD in children during clinical trials using the nonstimulant atomoxetine.  相似文献   
10.
医学插图的艺术创作   总被引:1,自引:1,他引:0  
介绍了医学插图艺术创作的方法:即在依据医学科学内容的基础上,遵循美学规律,运用科学的艺术表现形式,准确、形象、生动地表达出医学科学的深刻内涵,从而实现医学科学与艺术完美结合的创作目标。  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