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   21642篇
  免费   1694篇
  国内免费   460篇
耳鼻咽喉   3篇
儿科学   171篇
妇产科学   26篇
基础医学   640篇
口腔科学   9篇
临床医学   4500篇
内科学   12571篇
皮肤病学   12篇
神经病学   412篇
特种医学   312篇
外科学   862篇
综合类   2378篇
预防医学   284篇
眼科学   11篇
药学   1334篇
  10篇
中国医学   233篇
肿瘤学   28篇
  2024年   10篇
  2023年   457篇
  2022年   487篇
  2021年   1035篇
  2020年   1013篇
  2019年   1028篇
  2018年   921篇
  2017年   693篇
  2016年   677篇
  2015年   678篇
  2014年   1489篇
  2013年   1453篇
  2012年   996篇
  2011年   1021篇
  2010年   910篇
  2009年   983篇
  2008年   1046篇
  2007年   1078篇
  2006年   948篇
  2005年   860篇
  2004年   711篇
  2003年   703篇
  2002年   545篇
  2001年   496篇
  2000年   411篇
  1999年   370篇
  1998年   331篇
  1997年   304篇
  1996年   231篇
  1995年   227篇
  1994年   191篇
  1993年   187篇
  1992年   184篇
  1991年   151篇
  1990年   166篇
  1989年   128篇
  1988年   118篇
  1987年   95篇
  1986年   90篇
  1985年   73篇
  1984年   62篇
  1983年   52篇
  1982年   45篇
  1981年   30篇
  1980年   26篇
  1979年   23篇
  1978年   24篇
  1977年   16篇
  1976年   9篇
  1971年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
Secondary tricuspid regurgitation (TR) caused by right ventricular enlargement in the setting of left heart disease/pulmonary hypertension has been well described. In contrast, that associated with right atrial enlargement—atrial functional TR (AF‐TR)—remains largely underappreciated. AF‐TR most often occurs in the setting of lone atrial fibrillation, although it is also seen in its absence (idiopathic AF‐TR). Several recent studies have found that the prevalence, hemodynamic significance, and prognosis of AF‐TR are not inconsequential, suggesting increased physician awareness of this novel clinical entity is warranted. This article discusses the pathogenesis, echocardiographic findings, and treatment of this underappreciated cause of secondary TR.  相似文献   
4.
5.
6.
7.
8.
《Clinical neurophysiology》2020,131(1):259-264
ObjectivesFasciculation potentials (FP) are an important consideration in the electrophysiological diagnosis of ALS. Muscle ultrasonography (MUS) has a higher sensitivity in detecting fasciculations than electromyography (EMG), while in some cases, it is unable to detect EMG-detected fasciculations. We aimed to investigate the differences of FP between the muscles with and without MUS-detected fasciculations (MUS-fas).MethodsThirty-one consecutive patients with sporadic ALS were prospectively recruited and in those, both needle EMG and MUS were performed. Analyses of the amplitude, duration, and number of phases of EMG-detected FPs were performed for seven muscles per patient, and results were compared between the muscles with and without MUS-fas in the total cohort.ResultsThe mean amplitude and phase number of FP were significantly lower in patients with EMG-detected FP alone (0.39 ± 0.25 mV and 3.21 ± 0.88, respectively) than in those with both FP and MUS-fas (1.22 ± 0.92 mV and 3.74 ± 1.39, respectively; p < 0.0001 and p = 0.017, Welch’s t-test).ConclusionSmall FP may be undetectable with MUS. MUS cannot replace EMG in the diagnostic approach for ALS.SignificanceClinicians should use a combination of EMG and MUS for the detection and quantitative analysis of fasciculation in ALS.  相似文献   
9.
Abstract

Objective

The sex, age, medical history, treatment, tobacco use, race risk (SAMe-TT2R2) Score; the sex, age, medical history, treatment, tobacco use, genotype combination (SAMe-TT2G2) Score; and the so-called modified SAMe-TT2R2 scores have been proposed to predict the anticoagulation quality for patients with non-valvular atrial fibrillation (NVAF). The data from a prospective controlled study is used to validate the SAMe-TT2R2 and SAMe-TT2G2 scores in Chinese NVAF patients treated with warfarin and to evaluate the association of factors with time in therapeutic range (TTR) to predict the quality of oral anticoagulation control.  相似文献   
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