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   2821篇
  免费   359篇
  国内免费   40篇
耳鼻咽喉   21篇
儿科学   128篇
妇产科学   36篇
基础医学   190篇
口腔科学   34篇
临床医学   410篇
内科学   760篇
皮肤病学   70篇
神经病学   279篇
特种医学   367篇
外科学   497篇
综合类   51篇
一般理论   2篇
预防医学   132篇
眼科学   32篇
药学   104篇
中国医学   1篇
肿瘤学   106篇
  2023年   56篇
  2022年   18篇
  2021年   50篇
  2020年   99篇
  2019年   24篇
  2018年   107篇
  2017年   80篇
  2016年   72篇
  2015年   78篇
  2014年   125篇
  2013年   143篇
  2012年   107篇
  2011年   87篇
  2010年   107篇
  2009年   128篇
  2008年   83篇
  2007年   84篇
  2006年   90篇
  2005年   75篇
  2004年   74篇
  2003年   50篇
  2002年   73篇
  2001年   76篇
  2000年   71篇
  1999年   75篇
  1998年   90篇
  1997年   104篇
  1996年   86篇
  1995年   78篇
  1994年   60篇
  1993年   56篇
  1992年   55篇
  1991年   34篇
  1990年   48篇
  1989年   77篇
  1988年   61篇
  1987年   39篇
  1986年   43篇
  1985年   41篇
  1984年   22篇
  1983年   20篇
  1982年   24篇
  1981年   24篇
  1980年   19篇
  1979年   22篇
  1978年   24篇
  1977年   22篇
  1976年   18篇
  1975年   17篇
  1974年   14篇
排序方式: 共有3220条查询结果,搜索用时 375 毫秒
71.
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   
72.
73.
74.
75.
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   
76.
77.
78.
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   
79.
Sleep disordered breathing (SDB) is a complication of obesity estimated to occur in about 4–6% of overweight individuals. These respiratory disturbances during sleep incorporate a number of conditions including snoring, upper airway resistance syndrome and obstructive sleep apnoea syndrome (OSAS). It is thought that as well as having deleterious effects on sleep quality these conditions may also promote cardiovascular and hormonal changes leading to an elevated blood pressure and an increased incidence of cardiovascular morbidity. Evidence reviewed here points to an alteration in sympathovagal balance, baroreceptor sensitivity, insulin resistance and leptin, growth hormone and lipid levels. Whether these changes are a consequence of the associated obesity or the SDB itself remains to be proven.  相似文献   
80.
Colonic perfusion studies in 10 southern Indian patients with tropical sprue and nine matched healthy adults revealed a defect of water and sodium absorption from the colon in sprue. Heat-labile and heat-stable enterotoxin production was not detected in coliforms cultured from the feces of any of the 19 subjects. The 24-hr fecal bile acid output was increased in patients with sprue, but fecal aqueous bile acid concentrations remained within normal limits, and these did not correlate with defects in colonic water and sodium absorption. Fecal free fatty acid excretion was markedly increased in sprue. There was a negative correlation between fecal excretion of unsaturated free fatty acids and colonic water and sodium absorption.  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