全文获取类型
收费全文 | 90662篇 |
免费 | 6753篇 |
国内免费 | 2256篇 |
专业分类
耳鼻咽喉 | 185篇 |
儿科学 | 3205篇 |
妇产科学 | 824篇 |
基础医学 | 5945篇 |
口腔科学 | 851篇 |
临床医学 | 13970篇 |
内科学 | 30737篇 |
皮肤病学 | 142篇 |
神经病学 | 1560篇 |
特种医学 | 2793篇 |
外国民族医学 | 1篇 |
外科学 | 7571篇 |
综合类 | 15802篇 |
现状与发展 | 5篇 |
一般理论 | 3篇 |
预防医学 | 3672篇 |
眼科学 | 196篇 |
药学 | 7515篇 |
88篇 | |
中国医学 | 4336篇 |
肿瘤学 | 270篇 |
出版年
2024年 | 196篇 |
2023年 | 1316篇 |
2022年 | 2300篇 |
2021年 | 3372篇 |
2020年 | 3564篇 |
2019年 | 3228篇 |
2018年 | 3052篇 |
2017年 | 2680篇 |
2016年 | 2510篇 |
2015年 | 2784篇 |
2014年 | 5978篇 |
2013年 | 5992篇 |
2012年 | 4771篇 |
2011年 | 5333篇 |
2010年 | 4315篇 |
2009年 | 4116篇 |
2008年 | 4176篇 |
2007年 | 4426篇 |
2006年 | 3865篇 |
2005年 | 3651篇 |
2004年 | 2987篇 |
2003年 | 2716篇 |
2002年 | 2344篇 |
2001年 | 2203篇 |
2000年 | 1803篇 |
1999年 | 1797篇 |
1998年 | 1557篇 |
1997年 | 1514篇 |
1996年 | 1235篇 |
1995年 | 1116篇 |
1994年 | 1099篇 |
1993年 | 861篇 |
1992年 | 849篇 |
1991年 | 741篇 |
1990年 | 632篇 |
1989年 | 538篇 |
1988年 | 494篇 |
1987年 | 475篇 |
1986年 | 442篇 |
1985年 | 462篇 |
1984年 | 426篇 |
1983年 | 276篇 |
1982年 | 300篇 |
1981年 | 245篇 |
1980年 | 206篇 |
1979年 | 177篇 |
1978年 | 144篇 |
1977年 | 107篇 |
1976年 | 97篇 |
1975年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《The Journal of thoracic and cardiovascular surgery》2023,165(1):94-103.e24
ObjectiveNew-onset postoperative atrial fibrillation (POAF) after cardiac surgery is common, with rates up to 60%. POAF has been associated with early and late stroke, but its association with other cardiovascular outcomes is less known. The objective was to perform a meta-analysis of the studies reporting the association of POAF with perioperative and long-term outcomes in patients with cardiac surgery.MethodsWe performed a systematic review and a meta-analysis of studies that presented outcomes for cardiac surgery on the basis of the presence or absence of POAF. MEDLINE, EMBASE, and the Cochrane Library were assessed; 57 studies (246,340 patients) were selected. Perioperative mortality was the primary outcome. Inverse variance method and random model were performed. Leave-one-out analysis, subgroup analyses, and metaregression were conducted.ResultsPOAF was associated with perioperative mortality (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.58-2.33), perioperative stroke (OR, 2.17; 95% CI, 1.90-2.49), perioperative myocardial infarction (OR, 1.28; 95% CI, 1.06-1.54), perioperative acute renal failure (OR, 2.74; 95% CI, 2.42-3.11), hospital (standardized mean difference, 0.80; 95% CI, 0.53-1.07) and intensive care unit stay (standardized mean difference, 0.55; 95% CI, 0.24-0.86), long-term mortality (incidence rate ratio [IRR], 1.54; 95% CI, 1.40-1.69), long-term stroke (IRR, 1.33; 95% CI, 1.21-1.46), and longstanding persistent atrial fibrillation (IRR, 4.73; 95% CI, 3.36-6.66).ConclusionsThe results suggest that POAF after cardiac surgery is associated with an increased occurrence of most short- and long-term cardiovascular adverse events. However, the causality of this association remains to be established. 相似文献
2.
3.
Wojciech Szychta M.D. Ph.D. Gheorghe Cerin M.D. Ph.D. F.E.S.C. Bogdan Adrian Popa M.D. Armienti Felice M.D. Guido Lanzillo M.D. Ph.D. Marco Diena M.D. Grzegorz Opolski M.D. Ph.D. F.E.S.C. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1040-1043
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning. 相似文献
4.
Dynamic LVOT Obstruction and Aortic Stenosis in the Same Patient: A Case of Challenging Doppler Hemodynamics 下载免费PDF全文
Matthew W. Parker M.D. Francis J. Kiernan M.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1030-1032
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction. 相似文献
5.
Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study 下载免费PDF全文
6.
Moises Rodriguez-Gonzalez Antonio Moruno Tirado Reza Hosseinpour Jose Santos de Soto 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(4):350-356
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic. 相似文献
7.
8.
9.
10.
《The Journal of thoracic and cardiovascular surgery》2023,165(1):149-158.e4
BackgroundCoronary artery bypass grafting (CABG) improves survival in patients with heart failure and severely reduced left ventricular systolic function (LVEF). Limited data exist regarding adverse cardiovascular event rates after CABG in patients with heart failure with midrange ejection fraction (HFmrEF; LVEF > 40% and < 55%).MethodsWe analyzed data on isolated CABG patients from the Veterans Affairs national database (2010-2019). We stratified patients into control (normal LVEF and no heart failure), HFmrEF, and heart failure with reduced LVEF (HFrEF) groups. We compared all-cause mortality and heart failure hospitalization rates between groups with a Cox model and recurrent events analysis, respectively.ResultsIn 6533 veterans, HFmrEF and HFrEF was present in 1715 (26.3%) and 566 (8.6%) respectively; the control group had 4252 (65.1%) patients. HFrEF patients were more likely to have diabetes mellitus (59%), insulin therapy (36%), and previous myocardial infarction (31%). Anemia was more prevalent in patients with HFrEF (49%) as was a lower serum albumin (mean, 3.6 mg/dL). Compared with the control group, a higher risk of death was observed in the HFmrEF (hazard ratio [HR], 1.3 [1.2-1.5)] and HFrEF (HR, 1.5 [1.2-1.7]) groups. HFmrEF patients had the higher risk of myocardial infarction (subdistribution HR, 1.2 [1-1.6]; P = .04). Risk of heart failure hospitalization was higher in patients with HFmrEF (HR, 4.1 [3.5-4.7]) and patients with HFrEF (HR, 7.2 [6.2-8.5]).ConclusionsHeart failure with midrange ejection fraction negatively affects survival after CABG. These patients also experience higher rates myocardial infarction and heart failure hospitalization. 相似文献