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   26384篇
  免费   2082篇
  国内免费   709篇
耳鼻咽喉   661篇
儿科学   520篇
妇产科学   699篇
基础医学   1780篇
口腔科学   524篇
临床医学   3047篇
内科学   8741篇
皮肤病学   31篇
神经病学   254篇
特种医学   1191篇
外国民族医学   2篇
外科学   5119篇
综合类   3391篇
现状与发展   1篇
预防医学   547篇
眼科学   1014篇
药学   968篇
  8篇
中国医学   270篇
肿瘤学   407篇
  2024年   28篇
  2023年   584篇
  2022年   764篇
  2021年   1476篇
  2020年   1494篇
  2019年   1422篇
  2018年   1301篇
  2017年   968篇
  2016年   894篇
  2015年   946篇
  2014年   1816篇
  2013年   1723篇
  2012年   1211篇
  2011年   1428篇
  2010年   1132篇
  2009年   1135篇
  2008年   1063篇
  2007年   1091篇
  2006年   1046篇
  2005年   965篇
  2004年   737篇
  2003年   737篇
  2002年   658篇
  2001年   594篇
  2000年   450篇
  1999年   433篇
  1998年   335篇
  1997年   285篇
  1996年   294篇
  1995年   280篇
  1994年   236篇
  1993年   218篇
  1992年   177篇
  1991年   151篇
  1990年   139篇
  1989年   123篇
  1988年   92篇
  1987年   100篇
  1986年   102篇
  1985年   105篇
  1984年   101篇
  1983年   63篇
  1982年   67篇
  1981年   41篇
  1980年   48篇
  1979年   26篇
  1978年   26篇
  1977年   13篇
  1976年   19篇
  1973年   14篇
排序方式: 共有10000条查询结果,搜索用时 139 毫秒
1.
ObjectiveDeterioration of the native aortic valve function by a late progression of rheumatic disease is not infrequent in patients who underwent rheumatic mitral valve surgery; however, this phenomenon has not been clearly quantified.MethodsA total of 1155 consecutive patients (age 52.0 ± 12.9 years; 807 female) who underwent rheumatic mitral valve surgery without concomitant aortic valve surgery from 1997 to 2015 were enrolled. The primary end point was the composite of progression to severe aortic valve dysfunction or a requirement of subsequent aortic valve replacements during follow-up. To determine the risk factors of the primary outcome, we performed the generalized linear mixed model.ResultsThe baseline severities of aortic valve were none to trivial in 880 patients (76.2%), mild in 256 patients (22.2%), and moderate in 19 patients (1.6%). The latest 1062 echocardiographic assessments (91.9%; median, 81.2 postoperative months; interquartile range, 37.3-132.1 months) demonstrated 26 cases (0.33%/patient-year) meeting the primary end point during follow-up. Cumulative incidence of the primary end point at 10 years was 0.4% ± 0.3% and 7.4% ± 2.5% depending on the presence of mild or greater aortic valve dysfunction at baseline (P < .01). In multivariable analyses, aortic valve peak pressure gradient (odds ratio, 1.14; 95% confidence interval, 1.10-1.20), aortic regurgitation degree (mild over none: odds ratio, 3.26; 95% confidence interval, 1.15-9.23), and time (odds ratio, 1.30; 95% confidence interval 1.19-1.41) were significantly associated with the occurrence of the primary end point.ConclusionsProgression of severe aortic valve dysfunction and the need for aortic valve replacement are uncommon in patients undergoing rheumatic mitral valve surgery. However, such events were relatively common among those with mild or greater aortic valve dysfunction at the time of mitral valve surgery.  相似文献   
2.
3.
AimsMyocardial strain analysis enables more precise assessment of cardiac performance but is relatively load dependent. New tools have been developed with afterload adjustment. Our objective was to assess myocardial work (MW) in patients with repaired aortic coarctation (rACo).MethodsProspective study of consecutive patients with rACo who underwent a routine transthoracic echocardiogram in 2018 and 2019 at our center. Patients with significant aortic valve disease, pacemaker, or other congenital heart diseases (except for mild bicuspid aortic valve disease) were excluded. Global longitudinal strain with two dimensional speckle tracking analysis and MW were obtained (GWI:Global Work Index; GCW: Global Constructive Work; GWW: Global Wasted Work; GWE: Global Work Efficiency). Blood pressure was measured in the patient's right arm.ResultsWe included 42 patients in the analysis, mean age of 37±10 years, 38% males. In this group, 52% had hypertension and 64% had a concomitant bicuspid aortic valve. In comparison to previously published reference values, patients with rACo had significantly lower GWI (1807 vs. 1896 mmHg%) and GCW (2173 vs. 2232 mmHg%) (p<0.001), particularly in males. Systolic blood pressure is an independent predictor for GWI (β=0.432) and for GCW (β=0.534) and GLS an independent predictor of all MW parameters (β>0.594). Neither age nor gender were independent predictors.ConclusionsIn patients with rACo, there are some signs of left ventricular dysfunction with a reduction in GCW and GWI and with preserved GWE, despite normal ejection fraction and strain.  相似文献   
4.
《Heart rhythm》2022,19(11):1890-1898
  1. Download : Download high-res image (206KB)
  2. Download : Download full-size image
  相似文献   
5.
The aim of this retrospective study was to investigate the accuracy of dynamic navigation for the placement of intentionally tilted implants in the posterior maxilla. The study included 12 patients with edentulism or continuous multiple tooth loss, who had 48 implants inserted under dynamic navigation guidance in the posterior maxilla. Twenty-four implants near maxillary sinuses were intentionally tilted. The average platform deviation was 1.3 ± 0.4 mm (range 0.8–2.3 mm), apex deviation was 1.1 ± 0.5 mm (range 0.2–2.3 mm), and axis deviation was 3.1 ± 1.0° (range 1.8–6.7°). The other 24 implants were axially positioned. The average platform deviation was 1.5 ± 0.5 mm (range 0.7–3.1 mm), apex deviation was 1.3 ± 0.7 mm (range 0.5–3.1 mm), and axis deviation was 3.2 ± 1.5° (range 1.5–7.7°). There was no significant difference in platform deviation, apex deviation, or axis deviation between the tilted implants and implants in the axial position (P > 0.05). This analysis indicates that a dynamic navigation system can be used as a method of guidance to place intentionally tilted implants as accurately as axially positioned implants in the posterior maxilla, thereby preventing damage to the maxillary sinuses and the need to graft bone.  相似文献   
6.
7.
8.
9.
《Cardiology Clinics》2021,39(4):495-503
  相似文献   
10.
Mechanical intravascular hemolysis is frequently observed following procedures on heart valves and uncommonly observed in native valvular disease. In most cases, its severity is mild. Nevertheless, it can be clinically significant and even life threatening, requiring multiple blood transfusions and renal replacement therapy. This paper reviews the current knowledge on mechanical intravascular hemolysis in valvular disease, before and after correction, focusing on pathophysiology, approach to diagnosis, and impact of other hematological conditions on the resultant anemia. The importance of a multidisciplinary management is underscored. Laboratory data are provided about subclinical hemolysis that is commonly observed following the implantation of surgical and transcatheter valve prostheses and devices. Finally, clinical scenarios are reviewed and current medical and surgical treatments are discussed, including alternative options for inoperable patients.  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