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   247689篇
  免费   12991篇
  国内免费   6899篇
耳鼻咽喉   2997篇
儿科学   8397篇
妇产科学   3061篇
基础医学   18556篇
口腔科学   5224篇
临床医学   29064篇
内科学   40146篇
皮肤病学   3071篇
神经病学   11467篇
特种医学   13540篇
外国民族医学   23篇
外科学   43782篇
综合类   24928篇
现状与发展   25篇
预防医学   15582篇
眼科学   4836篇
药学   25464篇
  119篇
中国医学   5892篇
肿瘤学   11405篇
  2023年   2223篇
  2022年   4595篇
  2021年   10972篇
  2020年   6061篇
  2019年   11744篇
  2018年   6195篇
  2017年   5662篇
  2016年   7723篇
  2015年   10570篇
  2014年   19664篇
  2013年   17240篇
  2012年   20623篇
  2011年   17660篇
  2010年   16087篇
  2009年   15567篇
  2008年   14005篇
  2007年   14051篇
  2006年   12003篇
  2005年   8264篇
  2004年   4588篇
  2003年   3831篇
  2002年   3037篇
  2001年   2495篇
  2000年   2141篇
  1999年   1432篇
  1998年   1774篇
  1997年   1623篇
  1996年   1339篇
  1995年   1335篇
  1994年   1265篇
  1993年   987篇
  1992年   1185篇
  1991年   1050篇
  1990年   1094篇
  1989年   1055篇
  1988年   986篇
  1987年   870篇
  1986年   717篇
  1985年   1646篇
  1984年   1771篇
  1983年   1293篇
  1982年   1384篇
  1981年   1358篇
  1980年   1172篇
  1979年   1009篇
  1978年   775篇
  1977年   777篇
  1976年   670篇
  1975年   437篇
  1974年   460篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
12.
13.
14.
15.
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   
16.
《Seminars in Arthroplasty》2022,32(4):681-687
BackgroundThe objective of this study was to compare complication rates between patients undergoing reverse shoulder arthroplasty (RSA) after a prior open reduction and internal fixation (ORIF) for proximal humerus fracture (PHF) to those undergoing RSA as a primary treatment for PHFs, glenohumeral osteoarthritis, or rotator cuff tear arthropathy (CTA).MethodsPatients who underwent RSA between 2015 and 2020 were identified in the Mariner database. Patients were separated into 3 mutually exclusive groups: (1) RSA for osteoarthritis, rotator cuff tear, or CTA (Control-RSA); (2) RSA as a primary treatment for PHF (PHF-RSA); and (3) RSA for patients with prior ORIF of PHFs (ORIF-RSA). Ninety-day medical and 2-year postoperative surgical complications were identified. In addition, patients in the PHF-RSA group were subdivided into those undergoing RSA for PHF within 3 months of the fracture (acute) vs. those treated greater than 3 months from diagnosis (delayed). Multivariate regression was performed to control for differences in comorbidities and demographics.ResultsA total of 30,824 patients underwent primary RSA for arthritis or CTA, 5389 patients underwent RSA as a primary treatment for a PHF, and 361 patients underwent RSA after ORIF of a PHF. ORIF before RSA was associated with an increased risk of overall revision (odds ratio [OR] 2.45, P = .002), infection (OR 2.40, P < .001), instability (OR 2.43, P < .001), fracture (OR 3.24, P = .001), minor medical complications (OR 1.59, P = .008), and readmission (OR 2.55, P = .001) compared with the Control-RSA cohort. RSA as a primary treatment for PHF was associated with an increased risk of 2-year revision (OR 1.60, P < .001), infection (OR 1.51, P < .001), instability (OR 2.84, P < .001), and fracture (OR 2.54, P < .001) in addition to major medical complications (OR 2.02, P < .001), minor medical complications (OR 1.92, P < .001), 90-day emergency department visits (OR 1.26, P < .001) and 90-day readmission (OR 2.03, P < .001) compared with the Control-RSA cohort. The ORIF-RSA group had an increased risk of periprosthetic infection (OR 1.94, P = .002) when compared with the PHF-RSA cohort. There were no differences in medical or surgical complications in the RSA-PHF cohort between patients treated in an acute or delayed fashion.ConclusionRSA following ORIF of a PHF is associated with increased complications compared with patients undergoing RSA for nonfracture indications. Prior ORIF of a PHF is also an independent risk factor for postoperative infection after RSA compared with patients who undergo RSA as a primary operation for fracture. The timing of RSA as a primary operation for PHF does not appear to impact the rates of postoperative medical and surgical complications.  相似文献   
17.
孙悦  刘馨甜  张弘 《安徽医药》2022,26(11):2126-2130
角膜移植为治疗角膜盲的主要手段,而角膜移植排斥则是决定角膜植片存活时间和病人术后视力的关键。角膜得益于其特殊的眼前节“免疫赦免”状态,使得角膜移植能够在众多器官移植中享有极低的排斥率,然而排斥反应发生的风险依然存在。当机体处于遗传物质异常的特殊状态时,宿主将通过宏观调控“免疫赦免”状态对植片的保护作用或受体对移植物排异产生的有害作用,延迟或促进角膜移植排斥反应的发生,进而影响移植物的存活时间和透明度。该文综述与角膜移植排斥相关的多种全身性遗传疾病,总结全身性遗传疾病对角膜移植排斥的影响,浅析其发生的病理生理学机制以及诊疗的特殊性。  相似文献   
18.
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area.  相似文献   
19.
《Injury》2023,54(6):1702-1710
IntroductionPatients with cirrhosis are at higher risk for morbidity after injury. Acetabular fractures represent a highly morbid injury pattern. Few studies have specifically examined an effect of cirrhosis on risk of complications after acetabular fracture. We hypothesized that cirrhosis is independently associated with increased risk of inpatient complications following operative treatment of acetabular fractures.MethodsAdults patients with acetabular fracture who underwent operative treatment were identified from Trauma Quality Improvement Program data from 2015 to 2019. Patients with and without cirrhosis were matched on a propensity score predicting cirrhotic status and inpatient complications based on patient, injury, and treatment characteristics. The primary outcome was overall complication rate. Secondary outcomes included serious adverse event rate, overall infection rate, and mortality.ResultsAfter propensity score matching, 137 cirrhosis+ and 274 cirrhosis- remained. No significant differences existed in observed characteristics after matching. Compared to cirrhosis- patients, cirrhosis+ patients experienced 43.4% (83.9 vs 40.5%, p < 0.001) greater absolute risk difference of any inpatient complication, 29.9% (51.8 vs 21.9%, p < 0.001) greater absolute risk difference of serious adverse events, 28.5% (41.6 vs 13.1%, p < 0.001) greater absolute risk difference of any infection, and 2.9% (2.9% vs 0.0%, p = 0.02) greater absolute risk difference of inpatient mortality.ConclusionCirrhosis is associated with higher rates of inpatient complications, serious adverse events, infection, and mortality among patients undergoing operative repair of acetabular fracture.Level of EvidencePrognostic Level III.  相似文献   
20.
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