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   7494篇
  免费   314篇
  国内免费   115篇
耳鼻咽喉   29篇
儿科学   283篇
妇产科学   37篇
基础医学   586篇
口腔科学   543篇
临床医学   894篇
内科学   1863篇
皮肤病学   7篇
神经病学   68篇
特种医学   597篇
外科学   1905篇
综合类   744篇
预防医学   95篇
眼科学   5篇
药学   216篇
  2篇
中国医学   24篇
肿瘤学   25篇
  2024年   12篇
  2023年   150篇
  2022年   292篇
  2021年   362篇
  2020年   297篇
  2019年   297篇
  2018年   267篇
  2017年   234篇
  2016年   231篇
  2015年   223篇
  2014年   538篇
  2013年   479篇
  2012年   358篇
  2011年   442篇
  2010年   321篇
  2009年   351篇
  2008年   344篇
  2007年   366篇
  2006年   337篇
  2005年   269篇
  2004年   230篇
  2003年   186篇
  2002年   166篇
  2001年   132篇
  2000年   112篇
  1999年   102篇
  1998年   77篇
  1997年   79篇
  1996年   56篇
  1995年   64篇
  1994年   63篇
  1993年   49篇
  1992年   50篇
  1991年   44篇
  1990年   39篇
  1989年   32篇
  1988年   30篇
  1987年   26篇
  1986年   28篇
  1985年   31篇
  1984年   20篇
  1983年   17篇
  1982年   28篇
  1981年   13篇
  1980年   11篇
  1979年   13篇
  1978年   17篇
  1976年   9篇
  1975年   7篇
  1974年   7篇
排序方式: 共有7923条查询结果,搜索用时 15 毫秒
51.
Seven percent of 400 patients with cervical spine fractures and/or dislocations had unusual lesions of the axis. The authors have analyzed axis injuries by review of radiographs and clinical data and have derived a classification of traumatic conditions. Uncommon traumatic axis abnormalities are discussed with reference to incidence, causes, clinical findings, mechanism of injury, and roentgen characteristics.Picker Scholar, James Picker Foundation  相似文献   
52.
In this study, we analyzed the extent and pattern of regression of left ventricular (LV) hypertrophy after aortic valve replacement in patients with aortic stenosis (AS) and compared the results with those of another group of patients with aortic regurgitation (AR). Seventy patients who underwent isolated aortic valve replacement were divided into 2 groups. Group 1 was comprised of 29 patients who underwent aortic valve replacement for aortic stenosis, and Group 2 of 41 patients who underwent aortic valve replacement for aortic regurgitation. A third group of 10 healthy subjects served as a healthy control group. Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up, a significant reduction in the left ventricular mass was found in both groups, but it remained significantly greater than in the healthy control group. The ratio of LV wall thickness to radius (th/r) in Group 1 decreased significantly, and at follow-up it was within the normal value. In Group 2, the th/r ratio increased, and at follow-up it was within the normal value. After aortic valve replacement, the wall thickness remained significantly greater than normal for patients with AS, and the chamber radius remained significantly greater than normal for patients with AR. For these reasons, LV hypertrophy still existed in both groups at postoperative follow-up. The actuarial survival rate was 85.3% at 16 years for Group 1 and 83.4% at 18 years for Group 2. There was no significant difference in the long-term survival rates between the 2 groups. Actuarial freedom from valve-related events was 91.9% at 16 years for Group 1 and 82% at 18 years for Group 2. There was no significant difference in the valve-related event free curves between groups. After 5 years of follow-up, th/r reached normal for both groups, indicating remodeling of the LV geometry after aortic valve replacement.  相似文献   
53.
目的 :比较不同类型错牙合畸形的牙弓形态。方法 :采用三维测量仪精密测量正常牙合及 4组不同类型错牙合(ClassⅠ双颌前突、ClassⅡ1、ClassⅡ2 、ClassⅢ )的原始模型 ,圆锥曲线模拟其牙弓形态。结果 :不同类型错牙合牙弓形态的差异有显著性 ,甚至某些分组的上下颌之间牙弓形态的差异也有显著性。结论 :临床上弯制弓丝时采用单一的标准牙弓形态是不完全科学的 ,应考虑错牙合的不同类型及其矫治前不同的牙弓形态以防止畸形复发。  相似文献   
54.
Three patients with patent ductus arteriosus and moderate aortic stenosis had a marked reduction in aortic valve gradient following transcatheter ductal occlusion. The hemodynamic effects of an aortopulmonary shunt on the severity of left ventricular outflow obstruction and the implications on intervention are discussed.  相似文献   
55.
The prognosis of Marfan syndrome in both adult and pediatric patients is primarily related to the cardiovascular complications. In infantile Marfan syndrome, although involvement of the mitral valve is the most frequently encountered cardiovascular lesion, the aortic root can be more worrisome because of its excessive dilatation, leading to aortic insufficiency or dissection. If the role of elective surgery is relatively well defined for adult patients, it is still debated during childhood. We report two patients, aged 22 months and 5 years, each presenting an aortic root aneurysm related to Marfan syndrome, and each treated with the Bentall procedure without specific age-related mortality or morbidity. These two patients experienced normal growth and were free of any complication for a follow-up period of 8 and 2 years, respectively. More than an absolute value of the aortic root dimension, it is the conjunction of the rate of progression of the aortic root dilatation, the degree and the duration of the aortic valve regurgitation, and its resulting left ventricular dysfunction that must be taken into consideration in choosing the surgical option.  相似文献   
56.
目的总结我院1993年8月至2004年5月29例胸主动脉瘤手术体外循环(CPB)经验。方法29例胸主动脉瘤患者,实施Bentall’s手术、主动脉次全弓及全弓置换术及升或胸降主动脉人工血管置换术。根据术式分别采用常规中低温CPB,中、深低温停循环加选择性脑灌注,选择性脑灌注加下半身灌注、部分股股转流等灌注方法。结果平均CPB时间(179·8±78·1)min。并发症以出血和感染为主。早期死亡2例,晚期死亡4例。死亡率20·7%。结论正确选择CPB方法及良好的CPB管理是胸主动脉瘤手术成功的保障。  相似文献   
57.
Regular follow-up is required in patients with previous intervention for coarctation of the aorta to detect recoarctation or aneurysm formation. In this study we describe the findings encountered on routine follow-up exams and we compare the use of contrast-enhanced 3D MR angiography (CE MRA) with fast spin-echo MRI (FSE) to study the thoracic aorta after previous intervention. In 51 consecutive patients previously treated for aortic coarctation, 74 MR studies of the thoracic aorta were performed during a 2-year period using CE MRA and FSE MRI. The thoracic aorta was evaluated for abnormalities of course, caliber, shape, and pathology of side branches. The CE MRA and FSE MRI studies were evaluated side by side by consensus of two reviewers evaluating which MR technique depicted the abnormalities of the thoracic aorta the best. Of 74 exams, six clinically important abnormalities were found: four aneurysms and two restenoses. Two small pseudoaneurysms were missed on the FSE studies. Contrast-enhanced MRA was judged to visualize aortic abnormalities better than FSE (47 of 74 MR studies) especially for the transverse aortic arch, coarctation site, left subclavian artery, and aortic arch configuration. For the ascending aorta and distal descending aorta, CE MRA and FSE performed equally well. Aortic diameters measured at four levels in the first 18 MRI studies showed no significant differences in diameter when measured by FSE or CE MRA (p = not significant). Clinically important abnormalities, such as aneurysm formation and restenosis, can be present years after treatment for aortic coarctation. In the regular follow-up of these patients, CE MRA may provide additional diagnostic information compared with FSE and should be included as part of the routine exam. Received: 3 April 2000; Revised: 5 July 2000; Accepted: 7 July 2000  相似文献   
58.
Congenital abnormality of the aortic arch is a diagnosis made most of the time incidentally in childhood, unless dysphagia or respiratory disorders occur before. A case of a complex aortic arch anomaly with an aneurysm of the right subclavian artery presenting as an isolated Horner's syndrome in an adult is reported herein. Magnetic resonance imaging led to this very unusual diagnosis. Received: 17 March 1999; Revised: 15 July 1999; Accepted: 13 August 1999  相似文献   
59.
目的:探讨椎弓根螺钉最佳入路及手术步骤。方法:对104例胸腰椎骨折脱位患者,分两组采用不同方法、步骤钻入椎弓根螺钉,并对其进行疗效比较。结果:经过技术改进后的方法较传统方法对骨折脱位的复位效果无明显差异,而两者在X线曝光次数、手术时间、出血量及并发症等方面存在显著性差异。结论:技术改进后的椎弓根螺钉进钉方法简单、安全、创伤小、疗效优良。  相似文献   
60.
目的探讨主动脉夹层患者的临床特征、诊断、治疗及预后。方法对56例主动脉夹层患者的病因、临床表现、影像学检查、分型、治疗和预后进行回顾性分析。结果主动脉夹层的常见原因为高血压;临床表现主要为胸、背部疼痛,CT和MRI检查确诊率高;A型患者的并发症发生率和死亡率显著高于B型患者;介入治疗临床效果较好。结论A型患者的预后较B型差,早期诊断、合理治疗可以改善患者的预后。  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