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   2372篇
  免费   345篇
  国内免费   40篇
耳鼻咽喉   13篇
儿科学   114篇
妇产科学   177篇
基础医学   133篇
口腔科学   31篇
临床医学   326篇
内科学   642篇
皮肤病学   70篇
神经病学   201篇
特种医学   306篇
外科学   394篇
综合类   36篇
预防医学   116篇
眼科学   25篇
药学   76篇
中国医学   2篇
肿瘤学   95篇
  2023年   52篇
  2022年   15篇
  2021年   31篇
  2020年   94篇
  2019年   16篇
  2018年   91篇
  2017年   69篇
  2016年   70篇
  2015年   66篇
  2014年   106篇
  2013年   124篇
  2012年   56篇
  2011年   58篇
  2010年   89篇
  2009年   120篇
  2008年   61篇
  2007年   61篇
  2006年   62篇
  2005年   45篇
  2004年   35篇
  2003年   32篇
  2002年   38篇
  2001年   60篇
  2000年   32篇
  1999年   51篇
  1998年   90篇
  1997年   103篇
  1996年   93篇
  1995年   91篇
  1994年   57篇
  1993年   61篇
  1992年   56篇
  1991年   48篇
  1990年   61篇
  1989年   78篇
  1988年   59篇
  1987年   46篇
  1986年   38篇
  1985年   36篇
  1984年   30篇
  1983年   12篇
  1982年   17篇
  1981年   16篇
  1980年   18篇
  1979年   18篇
  1978年   11篇
  1977年   12篇
  1976年   13篇
  1974年   10篇
  1971年   10篇
排序方式: 共有2757条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
Intermittent dysfunction of mechanical mitral valve prosthesis is an uncommon condition. It carries serious clinical implications if unrecognized. Here, we present a case of a 28‐year‐old female with a history of rheumatic multivalvular disease, for which she had undergone double valve replacement and tricuspid annuloplasty. Six months later, she presented with heart failure. Clinical examination revealed intermittent loss of closing clicks followed by a pansystolic murmur at the apex, suggestive of mitral prosthetic valve dysfunction. We highlight the echocardiographic findings of paroxysmal mitral valvular regurgitation secondary to prosthetic valve malfunction secondary to prosthetic valve thrombosis.  相似文献   
56.
Retroaortic course of coronary artery is a relative contraindication for device closure of an atrial septal defect. In this brief report, we demonstrate, for the first time, inferior aortic recess mimicking retroaortic left circumflex coronary artery in a patient with atrial septal defect. This distinction is important to avoid spurious diagnosis of anomalous coronary artery denying patient a chance of nonsurgical closure of atrial septal defect.  相似文献   
57.
Sinus of Valsalva aneurysm is a rare congenital cardiac abnormality and is usually diagnosed when it ruptures. An asymptomatic 55‐year‐old male of unruptured sinus of Valsalva aneurysm of noncoronary cusp was on medical follow‐up. At 2‐year follow‐up, there was thrombus formation in the aneurysm, mimicking right atrium tumor on 2D transthoracic echocardiography. Cardiac computed tomography showed filling defect in the aneurysm suggestive of thrombus. Considering the high risk of systemic emboli surgery was performed, and aneurysm was repaired with Dacron patch.  相似文献   
58.
59.
Saline contrast echocardiography is a well‐established modality for the diagnosis of right‐to‐left shunt lesions. In this brief report, we demonstrate, for the first time, its usefulness in the diagnosis of anomalous origin of right pulmonary artery from aorta.  相似文献   
60.
Prolonged esophageal pH monitoring is the most accurate method for detecting abnormal gastroesophageal reflux (GER) in patients with gastroesophageal reflux disease (GERD). However, some investigators have found that short-duration postprandial pH monitoring in the upright position is also useful, while others have failed to find such results. Therefore, we have compared a 6-hr period of pH monitoring (3-hr postprandial period after daytime meal and 3-hr supine period) with a total 24-hr period in detecting abnormal gastroesophageal reflux. Sixty-five patients (44 men, mean age 41.3 years) with GERD and 16 healthy volunteers (11 men, mean age 34.3 years) underwent 24-hr pH monitoring according to a standard protocol. Various reflux parameters during 24-hr pH monitoring were compared with reflux parameters during the 6-hr period. Abnormal GER was detected in 56 patients presenting with typical symptoms of GERD (sensitivity 86.2%). These patients could be further divided into upright (N=18), supine (N=15), and combined (N=23) refluxers, depending on the posture in which abnormal reflux occurred. Esophageal pH monitoring during the 3-hr postprandial upright period showed abnormal reflux in only 35 patients (sensitivity 53.8%;P<0.00005, compared with the 24-hr pH monitoring period). Abnormal GER was identified in 13 of 18 upright, 19 of 23 combined, and only one of 15 supine refluxers, as well as in two of nine patients with normal 24-hr pH-metry. However, inclusion of the 3-hr supine monitoring period in the 3-hr postprandial upright period improved detection of abnormal GER to 78.5% (51 patients;P=NS compared with 24-hr pH monitoring period). This was related mainly to improved detection of abnormal GER in supine refluxers (11 of 15; 73.3%). Esophageal acid exposure time correlated significantly with severity of esophagitis only during the total and supine periods of both the 24- and 6-hr periods and not during the upright period. Esophageal acid clearance correlated significantly with increasing grades of esophagitis for the supine and total periods only. We conclude that 3-hr postprandial pH monitoring, as has been conventionally practiced, is not appropriate in the detection of abnormal GER; inclusion of a supine period in the short-duration pH monitoring schedule increases the detection of pathological reflux. We therefore recommend that a supine period should be included in short-duration pH monitoring schedules. We also found that supine reflux was the most important factor in the development of esophagitis.  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