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   1085943篇
  免费   74555篇
  国内免费   1758篇
耳鼻咽喉   15091篇
儿科学   29365篇
妇产科学   26537篇
基础医学   153525篇
口腔科学   35526篇
临床医学   91781篇
内科学   217257篇
皮肤病学   23194篇
神经病学   84955篇
特种医学   41455篇
外国民族医学   105篇
外科学   170993篇
综合类   19311篇
现状与发展   2篇
一般理论   290篇
预防医学   78009篇
眼科学   24079篇
药学   81860篇
  3篇
中国医学   2794篇
肿瘤学   66124篇
  2021年   8956篇
  2019年   9082篇
  2018年   13342篇
  2017年   10266篇
  2016年   10812篇
  2015年   12465篇
  2014年   16961篇
  2013年   23738篇
  2012年   33797篇
  2011年   35177篇
  2010年   19956篇
  2009年   18827篇
  2008年   32423篇
  2007年   34095篇
  2006年   34214篇
  2005年   33376篇
  2004年   32054篇
  2003年   30466篇
  2002年   28276篇
  2001年   58903篇
  2000年   60672篇
  1999年   50565篇
  1998年   12093篇
  1997年   10603篇
  1996年   10713篇
  1995年   9890篇
  1994年   9223篇
  1993年   8465篇
  1992年   37789篇
  1991年   36142篇
  1990年   34779篇
  1989年   33903篇
  1988年   30834篇
  1987年   29952篇
  1986年   27922篇
  1985年   26703篇
  1984年   18948篇
  1983年   16045篇
  1982年   8302篇
  1979年   16621篇
  1978年   11145篇
  1977年   9488篇
  1976年   8245篇
  1975年   9124篇
  1974年   10965篇
  1973年   10362篇
  1972年   9772篇
  1971年   9234篇
  1970年   8840篇
  1969年   8337篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic.  相似文献   
46.
Respiratory cysts are benign lesions lined by normal respiratory epithelium. There are few reported cases localized to the orbit, while those of the eyelid are exceedingly rare. Respiratory cysts usually arise either from a non‐hereditary congenital malformation, where they are distinguished as choristomatous, or from trauma. Here, we report a case of a 53‐year‐old man who presented with a large right lower eyelid cyst that was histopathologically diagnosed as a respiratory cyst.  相似文献   
47.
A local pedicled vascularized bone flap can prevent the morbidity and cost of free bone flap surgery in small segmental bone defects or long cartilaginous defects of the head and neck. Such flaps can also be useful in patients who are high risk for surgery. The periosteal vascularity of the mandible can be used to design islanded facial artery-based bone flaps, which can be utilized to that extent. Two patients with a small segmental mandibulectomy defect and one patient with a long cricotracheal resection defect underwent reconstruction using three different designs of islanded facial artery osteomyomucosal/osseous flap (iFOMM). The patients had a minimum follow-up period of 18 months. All flaps were successful, with satisfactory healing and without any functional deficit or disease at last follow-up.  相似文献   
48.
49.
Blecha  S.  Weber-Carstens  S.  Bein  T. 《Der Anaesthesist》2019,68(6):343-352
Die Anaesthesiologie - Die Versorgungsforschung (VF) ist ein fachübergreifendes multidisziplinäres Forschungsgebiet, das die Kranken- und Gesundheitsversorgung sowie ihre...  相似文献   
50.

Background

Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.

Methods

A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.

Results

The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).

Conclusion

Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.

Level of Evidence

Therapeutic Level IV.  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