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   68300篇
  免费   5558篇
  国内免费   1809篇
耳鼻咽喉   131篇
儿科学   951篇
妇产科学   352篇
基础医学   2946篇
口腔科学   299篇
临床医学   12645篇
内科学   21598篇
皮肤病学   205篇
神经病学   1941篇
特种医学   2489篇
外国民族医学   4篇
外科学   4666篇
综合类   12417篇
现状与发展   6篇
一般理论   1篇
预防医学   5333篇
眼科学   73篇
药学   5986篇
  142篇
中国医学   2630篇
肿瘤学   852篇
  2024年   56篇
  2023年   1219篇
  2022年   1583篇
  2021年   3083篇
  2020年   3203篇
  2019年   2530篇
  2018年   2489篇
  2017年   2407篇
  2016年   2690篇
  2015年   2794篇
  2014年   5770篇
  2013年   5884篇
  2012年   4972篇
  2011年   4989篇
  2010年   3843篇
  2009年   3422篇
  2008年   3343篇
  2007年   3474篇
  2006年   2835篇
  2005年   2403篇
  2004年   1851篇
  2003年   1517篇
  2002年   1280篇
  2001年   1116篇
  2000年   830篇
  1999年   673篇
  1998年   652篇
  1997年   599篇
  1996年   423篇
  1995年   529篇
  1994年   429篇
  1993年   401篇
  1992年   332篇
  1991年   297篇
  1990年   227篇
  1989年   206篇
  1988年   203篇
  1987年   171篇
  1986年   133篇
  1985年   176篇
  1984年   131篇
  1983年   85篇
  1982年   104篇
  1981年   86篇
  1980年   51篇
  1979年   53篇
  1978年   30篇
  1977年   33篇
  1976年   21篇
  1975年   21篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
51.
52.
Introduction and objectivesAlthough automatic artificial intelligence (AI) coronary angiography (CAG) segmentation is arguably the first step toward future clinical application, it is underexplored. We aimed to (1) develop AI models for CAG segmentation and (2) assess the results using similarity scores and a set of criteria defined by expert physicians.MethodsPatients undergoing CAG were randomly selected in a retrospective study at a single center. Per incidence, an ideal frame was segmented, forming a baseline human dataset (BH), used for training a baseline AI model (BAI). Enhanced human segmentation (EH) was created by combining the best of both. An enhanced AI model (EAI) was trained using the EH. Results were assessed by experts using 11 weighted criteria, combined into a Global Segmentation Score (GSS: 0–100 points). Generalized Dice Score (GDS) and Dice Similarity Coefficient (DSC) were also used for AI models assessment.Results1664 processed images were generated. GSS for BH, EH, BAI and EAI were 96.9+/-5.7; 98.9+/-3.1; 86.1+/-10.1 and 90+/-7.6, respectively (95% confidence interval, p<0.001 for both paired and global differences). The GDS for the BAI and EAI was 0.9234±0.0361 and 0.9348±0.0284, respectively. The DSC for the coronary tree was 0.8904±0.0464 and 0.9134±0.0410 for the BAI and EAI, respectively. The EAI outperformed the BAI in all coronary segmentation tasks, but performed less well in some catheter segmentation tasks.ConclusionsWe successfully developed AI models capable of CAG segmentation, with good performance as assessed by all scores.  相似文献   
53.
目的:探讨改进Seldinger法经皮穿刺腹膜透析置管术在终末期肾病患者中的应用效果。方法:选取2019年12月~2020年12月于本院进行腹膜透析置管术的终末期肾病患者61例,随机分为观察组(31例)和对照组(30例),对照组患者采用常规开腹手术置管,观察组采用改进Seldinger法置管,比较两组患者完成置管手术的相关指标(手术时间、术后排气时间、切口长度、住院时间),术后3d、1个月患者并发症发生情况。结果:较对照组,观察组手术时间、术后排气时间均更短,腹部切口长度更短(P<0.05),两组患者住院时间比较(P>0.05),观察组穿刺成功率明显高于对照组(100.00%,80.00%,χ2=6.88,P=0.01)。较对照组,观察组患者术后3d并发症发生率明显低于对照组(22.58%,50.00%,χ2=4.97,P=0.03),观察组患者术后1个月并发症发生率明显低于对照组(19.35%,53.33%,χ2=7.05,P=0.01)。结论:对终末期肾病患者运用改进Seldinger法经皮穿刺腹膜透析置管术进行置管可有效缩短手术时间和术后排气时间,创口较小,患者术后早期、远期并发症较少,临床应用效果较好。  相似文献   
54.
王育光  刘志威 《肝脏》2022,27(1):38-41
目的通过信息化随访方式干预慢性乙型病毒性肝炎患者,对比分析其对患者疾病及用药依从性影响。方法收集2014年10月至2017年10月惠州市第六人民医院门诊及住院部诊断为慢性乙型病毒性肝炎、乙肝肝硬化患者,剔除不符合纳入条件患者,共纳入符合条件患者264例,有42例合并肝硬化。对纳入患者采取分层随机抽样方法进行分组,最终微信+电话随访组87例,电话随访组88例,对照组89例。随访并对比三组在2年后肝功能、肝硬化人数及停用恩替卡韦时间等不同差异。结果随访年后三组在失访人数上差异存在统计学意义,其中A组与B组2年后两组在ALT(Z=-3.218,P=0.02)、AST(Z=-2.749,P=0.03)、Alb(Z=1.746,P=0.04)、乙肝病毒DNA(Z=-3.231,P=0.02)指标差异具有统计学意义,而TBil、FIB-4指数、APRI、γ-GT指标差异无统计学意义。A组与C组2年后对比结果显示,两组在ALT(Z=-11.089,P<0.001)、AST(Z=-9.247,P=0.01)、TBil(Z=-7.623,P=0.01)、APRI(Z=-4.834,P=0.01)、γ-GT(Z=-2.867,P=0.03)、Alb(Z=3.187,P=0.02)、乙肝病毒DNA(Z=-10.078,P<0.001)指标差异具有统计学意义,而FIB-4指数指标差异无统计学意义。B组与C组2年后两组对比结果显示,两组在ALT(Z=-1.275,P=0.04)、AST(Z=-2.045,P=0.03)、TBil(Z=-3.762,P=0.02)、APRI(Z=-1.461,P=0.04)、γ-GT(Z=-2.254,P=0.03)、乙肝病毒DNA(Z=-1.782,P=0.04)指标差异具有统计学意义,而Alb、FIB-4指数指标差异无统计学意义。随访2年后A组肝硬化人数为12人,B组为16人,C组为24人。A组与B组(χ2=0.945,P=0.408)、B组与C组肝硬化人数(χ2=2.741,P=0.103)差异无统计学意义,而A、C两组肝硬化人数差异有统计学意义(χ2=6.843,P=0.013)。在2年时间内,A组有15例患者暂停使用恩替卡韦,B组有28例,C组有61例,三组停用恩替卡韦人数差异有统计学意义(χ2=25.061,P<0.001),通过Kaplan-meier分析,结果显示A组使用恩替卡韦时间长于B组(83.0%vs 68.5%,χ2=5.754,P=0.016)及C组(83.0%vs 33.7%,χ2=61.601,P<0.001),而B组使用时间长于C组(63.5%vs 33.7%,χ2=32.451,P<0.001)。结论通过对患者强化信息化干预,可以使患者服用抗乙肝病毒药物依从性提高,降低患者肝功能异常发生及肝硬化发病率。  相似文献   
55.
56.
57.
58.
BackgroundRecent guidelines for the treatment of moderate or severe ischemic mitral regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) have changed. This study assessed the real-world impact of changing guidelines on the management of IMR during CABG over time. We hypothesized that the utilization of mitral valve repair for IMR would decrease over time, whereas mitral valve replacement for severe IMR would increase.MethodsPatients undergoing CABG in a statewide collaborative database (2011-2020) were stratified by severity of IMR. Trends in mitral valve repair or replacement were evaluated. To account for differences of the patients, propensity score–matched analyses were used to compare patients with and without mitral intervention.ResultsA total of 11,676 patients met inclusion criteria, including 1355 (11.6%) with moderate IMR and 390 (3.3%) with severe IMR. The proportion of patients undergoing mitral intervention for moderate IMR decreased over time (2011, 17.7%; 2020, 7.5%; Ptrend = .001), whereas mitral replacement for severe IMR remained stable (2011, 11.1%; 2020, 13.3%; Ptrend = .14). Major morbidity was higher for patients with moderate IMR who underwent mitral intervention (29.1% vs 19.9%; P = .005). In a propensity analysis of 249 well-matched pairs, there was no difference in major morbidity (29.3% with mitral intervention vs 23.7% without; P = .16) or operative mortality (1.2% vs 2.4%; P = .5).ConclusionsConsistent with recent guideline updates, patients with moderate IMR were less likely to undergo mitral repair. However, the rate of replacement for severe IMR did not change. Mitral intervention during CABG did not increase operative mortality or morbidity.  相似文献   
59.
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   
60.
《Indian heart journal》2022,74(4):302-306
BackgroundThe alarming rise in prevalence of hypertension warrants psychosocial methods supplementing pharmacotherapy for better management and prevention of cardiac emergencies. The objective of the study was to assess the differential impact of the form and frequency of knowledge intervention on management of primary hypertension.Materials and methodThe study was conducted on 256 hypertensive patients recruited through purposive sampling at health centers in Hyderabad, India. Pretest post-test control group quasi-experimental design was adopted for the study. There were two forms of the knowledge intervention, namely ‘Direct Interaction’ and ‘Audio-Visual’. Each form was presented in two frequencies namely ‘single exposure’ and ‘double exposure’. The four groups were labelled as Direct Intervention Single (DIS), Direct Intervention Double (DID), Audio-Visual Single (AVS) and Audio-Visual Double (AVD). Adherence and management of hypertension were assessed at baseline and six weeks post experiment. Analysis of Covariance (ANCOVA) was applied using IBM SPSS Statistics version 20.ResultsANCOVA followed by Bonferroni Multiple Group Comparison Test revealed significant differences between the four intervention groups and control group on adherence (p< .001). In case of hypertension management significant differences were observed between Control group and DIS, DID (p < .001), Control and AVS (p < .01). Control group did not differ from AVD.ConclusionThere was a positive impact of Knowledge Intervention on adherence and management of hypertension. Double exposure in audio visual form was counterproductive in hypertension management.  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