全文获取类型
收费全文 | 56586篇 |
免费 | 3324篇 |
国内免费 | 1525篇 |
专业分类
耳鼻咽喉 | 348篇 |
儿科学 | 883篇 |
妇产科学 | 774篇 |
基础医学 | 3936篇 |
口腔科学 | 281篇 |
临床医学 | 7733篇 |
内科学 | 14332篇 |
皮肤病学 | 91篇 |
神经病学 | 3473篇 |
特种医学 | 5050篇 |
外国民族医学 | 2篇 |
外科学 | 8018篇 |
综合类 | 9371篇 |
现状与发展 | 5篇 |
预防医学 | 1239篇 |
眼科学 | 602篇 |
药学 | 3400篇 |
30篇 | |
中国医学 | 1291篇 |
肿瘤学 | 576篇 |
出版年
2024年 | 40篇 |
2023年 | 793篇 |
2022年 | 1147篇 |
2021年 | 2046篇 |
2020年 | 1984篇 |
2019年 | 1791篇 |
2018年 | 1812篇 |
2017年 | 1604篇 |
2016年 | 1627篇 |
2015年 | 1806篇 |
2014年 | 3762篇 |
2013年 | 3632篇 |
2012年 | 3100篇 |
2011年 | 3438篇 |
2010年 | 2943篇 |
2009年 | 2958篇 |
2008年 | 3062篇 |
2007年 | 3110篇 |
2006年 | 2857篇 |
2005年 | 2379篇 |
2004年 | 1914篇 |
2003年 | 1688篇 |
2002年 | 1403篇 |
2001年 | 1359篇 |
2000年 | 1033篇 |
1999年 | 893篇 |
1998年 | 882篇 |
1997年 | 789篇 |
1996年 | 609篇 |
1995年 | 656篇 |
1994年 | 588篇 |
1993年 | 505篇 |
1992年 | 464篇 |
1991年 | 368篇 |
1990年 | 326篇 |
1989年 | 268篇 |
1988年 | 269篇 |
1987年 | 242篇 |
1986年 | 188篇 |
1985年 | 220篇 |
1984年 | 174篇 |
1983年 | 95篇 |
1982年 | 147篇 |
1981年 | 102篇 |
1980年 | 84篇 |
1979年 | 80篇 |
1978年 | 68篇 |
1977年 | 37篇 |
1976年 | 43篇 |
1975年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
21.
22.
23.
《Indian heart journal》2022,74(3):182-186
BackgroundIt has been reported that significant endothelial dysfunction or clinically evident vasospasm can be associated with drug-eluting stents (DESs). However, the impact of DES associated coronary artery spasm (CAS) on long-term clinical outcomes has not been fully elucidated as compared with those of patients with vasospastic angina.MethodsA total of 2797 consecutive patients without significant coronary artery lesion (<70%), who underwent the Acetylcholine (Ach) provocation test, were enrolled between Nov 2004 and Oct 2010. DES-associated spasm was defined as significant CAS in proximal or distal to previously implanted DES site at follow-up angiography with Ach test. Patients were divided into two groups (DES-CAS; n = 108, CAS; n = 1878). For adjustment, propensity score matching (PSM) was done (C-statistics = 0.766, DES-CAS; n = 102, CAS; n = 102). SPSS 20 (Inc., Chicago, Illinois) was used to analyze this data.ResultsBaseline characteristics were worse in the DES-CAS group. After PSM, both baseline characteristics and the Ach test results were balanced except higher incidence of diffuse CAS and ECG change in the DES-CAS group. During Ach test, the incidence of diffuse spasm (93.1% vs. 81.3%, p = 0.012) and ST-T change (10.7% vs. 1.9%, p = 0.010) were higher in the DES-CAS group. At 3-year, before and after adjustment, the DES-CAS group showed a higher incidence of coronary revascularization (9.8% vs. 0.0%, p = 0.001), recurrent chest pain requiring follow up coronary angiography (CAG, 24.5% vs. 7.8%, p = 0.001) and major adverse cardiac events (MACEs, 9.8% vs. 0.9%, p < 0.005).ConclusionIn this study, DES associated CAS was associated with higher incidence of diffuse spasm, ST-T change and adverse 3-year clinical outcomes. Special caution should be exercised in this particular subset of patients. 相似文献
24.
《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
25.
《Journal of Cardiovascular Computed Tomography》2022,16(5):397-403
BackgroundPretest probability (PTP) calculators utilize epidemiological-level findings to provide patient-level risk assessment of obstructive coronary artery disease (CAD). However, their limited accuracies question whether dissimilarities in risk factors necessarily result in differences in CAD. Using patient similarity network (PSN) analyses, we wished to assess the accuracy of risk factors and imaging markers to identify ≥50% luminal narrowing on coronary CT angiography (CCTA) in stable chest-pain patients.MethodsWe created four PSNs representing: patient characteristics, risk factors, non-coronary imaging markers and calcium score. We used spectral clustering to group individuals with similar risk profiles. We compared PSNs to a contemporary PTP score incorporating calcium score and risk factors to identify ≥50% luminal narrowing on CCTA in the CT-arm of the PROMISE trial. We also conducted subanalyses in different age and sex groups.ResultsIn 3556 individuals, the calcium score PSN significantly outperformed patient characteristic, risk factor, and non-coronary imaging marker PSNs (AUC: 0.81 vs. 0.57, 0.55, 0.54; respectively, p ?< ?0.001 for all). The calcium score PSN significantly outperformed the contemporary PTP score (AUC: 0.81 vs. 0.78, p ?< ?0.001), and using 0, 1–100 and ?> ?100 cut-offs provided comparable results (AUC: 0.81 vs. 0.81, p ?= ?0.06). Similar results were found in all subanalyses.ConclusionCalcium score on its own provides better individualized obstructive CAD prediction than contemporary PTP scores incorporating calcium score and risk factors. Risk factors may not be able to improve the diagnostic accuracy of calcium score to predict ≥50% luminal narrowing on CCTA. 相似文献
26.
《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
27.
《Journal of vascular and interventional radiology : JVIR》2022,33(4):359-367.e8
PurposeTo review and to compare indirectly the outcomes of minimally invasive therapies for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia.Materials and MethodsA literature search via Medline and Cochrane Central databases was completed for randomized control studies published between January 2000 to April 2020 for the following therapies: Rezum, Urolift, Aquablation, and prostatic artery embolization (PAE). Data on the following variables were included: International prostate symptom score (IPSS), maximum urinary flow rate, quality of life, and postvoid residual (PVR). Standard mean differences between treatments were compared through a meta-analysis using transurethral resection of the prostate (TURP) to assess differences in treatment effect.ResultsThere was no significant difference in outcomes between therapies for IPSS at the 3, 6, and 12-month follow ups. Although outcomes for Rezum were only available out to 3 months, there were no consistently significant differences in outcomes when comparing Aquablation versus PAE versus Rezum. TURP PVR was significantly better than Urolift at 3, 6, and 12 months. No significant differences in minor or major adverse events were noted.ConclusionAlthough significant differences in outcomes were limited, Aquablation and PAE were the most durable at 12 months. PAE has been well studied on multiple randomized control trials with minimal adverse events while Aquablation has limited high quality data and has been associated with bleeding-related complications. 相似文献
28.
29.
目的 观察未破裂颅内动脉瘤(UIA)直径与其血流动力学、形态学及瘤壁强化(AWE)的关系。方法 对前瞻性纳入的85例UIA患者行数字减影血管造影(DSA)、高分辨率MR管壁成像(HRMR-VWI)及四维血流MRI (4D flow MRI),观察其100枚UIA的血流动力学、形态学及AWE,计算UIA纵横比(AR)、大小比(SR)、顶颈比(DNR)、高宽比(HWR)、强化率(ER)及壁面切应力(WSS);比较直径<7 mm (n=78)及≥ 7 mm (n=22) UIA各参数的差异。结果 直径<7 mm与≥ 7 mm UIA患者既往蛛网膜下腔出血(SAH)史、动脉瘤相关症状、SR、DNR、形态、AWE、ER及WSS差异均有统计学意义(P均<0.05)。多因素logistic回归分析显示,既往SAH史、UIA的SR、形态及ER为其直径≥ 7 mm的独立危险因素。WSS与UIA直径、SR及ER均呈负相关(r=-0.70、-0.67、-0.63,P均<0.001)。观察者间判断AWE的一致性极高(Kappa=0.87),测量ER及WSS的一致性均好(ICC=0.946、0.871,P均<0.001)。结论 既往SAH史,UIA的SR、形态及ER均为其直径≥ 7 mm的独立危险因素。 相似文献
30.
目的:探究风池穴不同刺法对椎动脉型颈椎病的临床疗效。方法:选择2018年4月—2019年1月北京中医药大学东直门医院针灸科门诊就诊的84例椎动脉型颈椎病患者作为研究对象,分为观察组43例、对照组41例。观察组采用短刺法针刺风池穴治疗,对照组采用平补平泻法针刺风池穴治疗,1个疗程后比较两组患者的ESCV、颈椎病症状分级量化表评分以及TCD相关指标,TCD指标观察基底动脉和双侧椎动脉的平均血流速度(Vm)、收缩期血流速度峰值(Vs)、血管搏动指数(PI)和血管阻力指数(RI)的变化。结果:治疗前后两组ESCV、颈椎病症状分级量化表评分比较,差异有统计学意义(P<0.05),且椎动脉、基底动脉的Vs、Vm较治疗前明显减慢,且观察组治疗效果优于对照组(P<0.05)。结论:针刺风池穴治疗椎动脉型颈椎病临床效果显著,且短刺法优于平补平泻法。 相似文献