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   39842篇
  免费   3611篇
  国内免费   809篇
耳鼻咽喉   170篇
儿科学   848篇
妇产科学   1834篇
基础医学   1952篇
口腔科学   293篇
临床医学   13177篇
内科学   6345篇
皮肤病学   441篇
神经病学   1614篇
特种医学   2420篇
外国民族医学   6篇
外科学   3824篇
综合类   5891篇
现状与发展   3篇
预防医学   1443篇
眼科学   641篇
药学   1625篇
  50篇
中国医学   393篇
肿瘤学   1292篇
  2024年   118篇
  2023年   594篇
  2022年   1110篇
  2021年   1365篇
  2020年   1684篇
  2019年   1455篇
  2018年   1475篇
  2017年   1483篇
  2016年   1460篇
  2015年   1498篇
  2014年   2675篇
  2013年   2656篇
  2012年   2092篇
  2011年   2344篇
  2010年   1920篇
  2009年   1871篇
  2008年   1954篇
  2007年   2085篇
  2006年   1879篇
  2005年   1671篇
  2004年   1446篇
  2003年   1211篇
  2002年   1038篇
  2001年   991篇
  2000年   783篇
  1999年   748篇
  1998年   617篇
  1997年   608篇
  1996年   532篇
  1995年   476篇
  1994年   392篇
  1993年   328篇
  1992年   284篇
  1991年   256篇
  1990年   197篇
  1989年   128篇
  1988年   132篇
  1987年   100篇
  1986年   106篇
  1985年   132篇
  1984年   97篇
  1983年   44篇
  1982年   73篇
  1981年   48篇
  1980年   32篇
  1979年   27篇
  1978年   19篇
  1977年   10篇
  1976年   10篇
  1973年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Imaging plays a very important role in the diagnosis of HCC. Indeed, in high-risk patients a noninvasive diagnosis can only be obtained by imaging in presence of typical features. These features include arterial enhancement followed by washout during the portal venous and/or delayed phases on CT scan or MRI. This pattern is quite specific and has been endorsed by both Western and Asian diagnostic guidelines. However, its sensitivity is not very high, especially for small lesions. Therefore ancillary signs may be needed to increase the reliability of the diagnosis. Recent hepatobiliary MRI contrast agents seem to be interesting to improve characterization of small nodules in the cirrhotic liver.  相似文献   
992.
Although surgically created aortopulmonary (AP) shunts are uncommon in the adult congenital heart disease population, they are often used in patients with pulmonary atresia. For these patients, the shunt is a vital supply of pulmonary blood flow and thus obstruction of the shunt may lead to pulmonary hypoperfusion and hypoxia thereby increasing morbidity and mortality. This report describes a safe and effective method of stenting the conduit with the hemodynamic support of peripheral cardiopulmonary bypass (PCB). Prior to the procedure, a multimodality assessment of a stenosis in a kinked AP conduit using computed tomography, angiography, intravascular ultrasound (IVUS), and pressure wire assessment (PWA) was utilized. While PCB, IVUS, and PWA have all been used to great effect in various clinical scenarios, the combined use of these techniques has not been previously been described in the setting of intervention in adult congenital heart disease. © 2013 Wiley Periodicals, Inc.  相似文献   
993.
994.
Spontaneous coronary artery dissection (SCAD) is under‐diagnosed and the true prevalence is underestimated. Unfortunately, SCAD is frequently missed on coronary angiogram since the arterial wall is not imaged with this test. Optical coherence tomography or intravascular ultrasound should be the true gold‐standard to diagnose SCAD. Given the elusive angiographic diagnosis of SCAD and the lack of familiarity with angiographic variants of SCAD, a diagnostic algorithm and angiographic classification for SCAD is proposed in this article. © 2013 Wiley Periodicals, Inc.  相似文献   
995.
996.
997.
BACKGROUNDBiliary dilation is frequently related to obstruction; however, non-obstructive factors such as age and previous cholecystectomy have also been reported. In the past two decades there has been a dramatic increase in opiate use/dependence and utilization of cross-sectional abdominal imaging, with increased detection of biliary dilation, particularly in patients who use opiates.AIMTo evaluate associations between opiate use, age, cholecystectomy status, ethnicity, gender, and body mass index utilizing our institution’s integrated informatics platform. METHODSOne thousand six hundred and eighty-five patients (20% sample) presenting to our Emergency Department for all causes over a 5-year period (2011-2016) who had undergone cross-sectional abdominal imaging and had normal total bilirubin were included and analyzed.RESULTSCommon bile duct (CBD) diameter was significantly higher in opiate users compared to non-opiate users (8.67 mm vs 7.24 mm, P < 0.001) and in patients with a history of cholecystectomy compared to those with an intact gallbladder (8.98 vs 6.72, P < 0.001). For patients with an intact gallbladder who did not use opiates (n = 432), increasing age did not predict CBD diameter (r2 = 0.159, P = 0.873). Height weakly predicted CBD diameter (r2 = 0.561, P = 0.018), but weight, body mass index, ethnicity and gender did not.CONCLUSIONOpiate use and a history of cholecystectomy are associated with CBD dilation in the absence of an obstructive process. Age alone is not associated with increased CBD diameter. These findings suggest that factors such as opiate use and history of cholecystectomy may underlie the previously-reported association of advancing age with increased CBD diameter. Further prospective study is warranted.  相似文献   
998.
999.
1000.
BACKGROUND Although endoscopic ultrasound(EUS) is now widely available and has an established role in adults, the utility of EUS and EUS-guided fine needle aspiration(EUS-FNA) in pediatrics is insufficiently described compared to adults and is supported by only a few studies.AIM To report the experience of a single tertiary center in the use of EUS and EUS-FNA in a pediatric population and to further assess its safety, feasibility, and clinical impact on management.METHODS A retrospective study of 13 children(aged 18 years or younger) identified from our medical database was conducted. A retrospective review of demographic data, procedure indications, EUS findings, and the clinical impact of EUS on the subsequent management of these patients was performed.RESULTS During the 4-year study period, a total of 13(1.7%) pediatric EUS examinations out of 749 EUS procedures were performed in our unit. The mean age of these 8 females and 5 males was 15.6 years(range: 6-18). Six of the 13 EUS examinations were pancreatobiliary(46.1%), followed by mediastinal 2/13(15.4%), peri-gastric 2/13(15.4%), abdominal lymphadenopathy 1/13(7.7%), tracheal 1/13(7.7%) and rectal 1/13(7.7%). Overall, EUS-FNA was performed in 7 patients(53.8%) with a diagnostic yield of 100%. The EUS results had a significant impact on clinical care in 10/13(77%) cases. No complications occurred in these patients during or after any of the procedures.CONCLUSION EUS and EUS-FNA in the pediatric population are safe, feasible, and have a significant clinical impact on the subsequent management; thus avoiding invasive and unnecessary procedures.  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