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   101802篇
  免费   8247篇
  国内免费   2432篇
耳鼻咽喉   303篇
儿科学   2951篇
妇产科学   1717篇
基础医学   8199篇
口腔科学   974篇
临床医学   12854篇
内科学   24852篇
皮肤病学   353篇
神经病学   2546篇
特种医学   3307篇
外国民族医学   9篇
外科学   7941篇
综合类   18525篇
现状与发展   5篇
一般理论   3篇
预防医学   9337篇
眼科学   384篇
药学   10541篇
  172篇
中国医学   5525篇
肿瘤学   1983篇
  2023年   1421篇
  2022年   2050篇
  2021年   3913篇
  2020年   4214篇
  2019年   3568篇
  2018年   3471篇
  2017年   3382篇
  2016年   3333篇
  2015年   3370篇
  2014年   7019篇
  2013年   7254篇
  2012年   6184篇
  2011年   6588篇
  2010年   5116篇
  2009年   4760篇
  2008年   4686篇
  2007年   4989篇
  2006年   4202篇
  2005年   3864篇
  2004年   3178篇
  2003年   2830篇
  2002年   2476篇
  2001年   2187篇
  2000年   1819篇
  1999年   1754篇
  1998年   1446篇
  1997年   1385篇
  1996年   1183篇
  1995年   1174篇
  1994年   1145篇
  1993年   859篇
  1992年   876篇
  1991年   776篇
  1990年   641篇
  1989年   619篇
  1988年   530篇
  1987年   459篇
  1986年   418篇
  1985年   497篇
  1984年   419篇
  1983年   271篇
  1982年   326篇
  1981年   294篇
  1980年   252篇
  1979年   218篇
  1978年   188篇
  1977年   158篇
  1976年   154篇
  1975年   136篇
  1974年   90篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.  相似文献   
3.
4.
BackgroundSelection of the transcatheter heart valve size for a mitral valve-in-valve procedure is based on the type and manufacturer’s labelled size. However, accurate information of surgical heart valve (SHV) size may not be available in the patient’s medical record. The purpose of this study is to establish reference data for computed tomography (CT) dimensions of commonly used mitral SHV in order to determine the manufacturer’s labelled size from a cardiac CT data set.MethodsCT datasets of 105 patients with surgical mitral bioprosthesis and available manufacturer labeled datasets were included in the analysis. CT derived valve dimensions were assessed by two observers using multiplanar reformats aligned with the basal sewing ring. A circular region of interest was used in a standardized fashion to minimize influence of image acquisition and reconstruction parameters. Interobserver variability was assessed by Bland-Altman analysis.ResultsThe CT-derived dimensions were stratified by valve size and type, and SHV properties were demonstrated for 5 common valve types. Variability of measurements was small and inter-observer limits of agreement were narrow. Stratified by SHV type, no overlap was noted for CT-derived dimensions among different SHV sizes . A reference table of CT characteristics of surgical mitral bioprosthesis types was created.ConclusionThe study provides reference CT data for determining the manufacturers’ labeled SHV size across a range of commonly used mitral SHVs. The findings will be important to help identify types of surgical mitral bioprosthesis utilizing CT characteristics for patients without SHV size documentation.  相似文献   
5.
目的探讨前瞻性护理干预在急性心力衰竭患者中的应用效果。方法选取2018年4月—2020年5月河南省某医院收治的122例急性心力衰竭患者为研究对象,采用随机数字表法分为观察组与对照组,每组61例。对照组患者采用常规护理,观察组患者采用前瞻性护理,比较2组患者的干预效果、并发症发生情况,干预前后焦虑自评量表(SAS)、抑郁自评量表(SDS)评分及护理满意度。结果观察组患者干预总有效率为95.08%,高于对照组的75.41%,差异有统计学意义(χ2=9.385,P=0.002)。观察组患者并发症发生率为3.28%,低于对照组的18.03%,差异有统计学意义(χ2=6.974,P=0.008)。2组患者干预后SAS及SDS评分均低于干预前,且观察组低于对照组,差异均有统计学意义(P<0.05)。观察组患者护理满意度为98.36%,高于对照组的86.89%,差异有统计学意义(χ2=4.319,P=0.038)。结论前瞻性护理干预用于急性心力衰竭患者,有助于改善患者负性情绪及减少并发症的发生。  相似文献   
6.
BackgroundInflammation surrounding the coronary arteries can be non-invasively assessed using pericoronary adipose tissue attenuation (PCAT). While PCAT holds promise for further risk stratification of patients with low coronary artery disease (CAD) prevalence, its value in higher risk populations remains unknown.MethodsCORE320 enrolled patients referred for invasive coronary angiography with known or suspected CAD. Coronary computed tomography angiography (CCTA) images were collected for 381 patients for whom clinical outcomes were assessed 5 years after enrollment. Using semi-automated image analysis software, PCAT was obtained and normalized for the right coronary (RCA), left anterior descending (LAD), and left circumflex arteries (LCx). The association between PCAT and major adverse cardiovascular events (MACE) during follow up was assessed using Cox regression models.ResultsThirty-seven patients were excluded due to technical failure. For the remaining 344 patients, median age was 62 (interquartile range, 55–68) with 59% having ≥1 coronary artery stenosis of ≥50% by quantitative coronary angiography. Mean attenuation values for PCAT in RCA, LAD, and LCx were ?74.9, ?74.2, and ?71.2, respectively. Hazard ratios and 95% confidence intervals (CI) for normalized PCAT in the RCA, LAD, and LCx for MACE were 0.96 (CI: 0.75–1.22, p ?= ?0.71), 1.31 (95% CI: 0.96–1.78, p ?= ?0.09), and 0.98 (95% CI: 0.78–1.22, p ?= ?0.84), respectively. For death, stroke, or myocardial infarction only, hazard ratios were 0.68 (0.44–1.07), 0.85 (0.56–1.29), and 0.57 (0.41–0.80), respectively.ConclusionsIn patients referred for invasive coronary angiography with suspected CAD, PCAT did not predict MACE during long term follow up. Further studies are needed to understand the relationship of PCAT with CAD risk.  相似文献   
7.
8.
9.
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