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   2700104篇
  免费   188971篇
  国内免费   7876篇
耳鼻咽喉   36409篇
儿科学   89914篇
妇产科学   74765篇
基础医学   378846篇
口腔科学   73612篇
临床医学   242937篇
内科学   534924篇
皮肤病学   65566篇
神经病学   223065篇
特种医学   105703篇
外国民族医学   752篇
外科学   404523篇
综合类   51485篇
现状与发展   5篇
一般理论   994篇
预防医学   201809篇
眼科学   60131篇
药学   195917篇
  8篇
中国医学   5651篇
肿瘤学   149935篇
  2021年   21032篇
  2019年   21645篇
  2018年   31361篇
  2017年   24313篇
  2016年   28530篇
  2015年   31972篇
  2014年   43098篇
  2013年   64279篇
  2012年   85941篇
  2011年   90068篇
  2010年   54230篇
  2009年   51704篇
  2008年   84373篇
  2007年   89837篇
  2006年   91627篇
  2005年   88128篇
  2004年   84716篇
  2003年   81967篇
  2002年   79098篇
  2001年   131367篇
  2000年   134206篇
  1999年   113087篇
  1998年   32156篇
  1997年   28663篇
  1996年   28811篇
  1995年   27863篇
  1994年   25489篇
  1993年   23809篇
  1992年   86304篇
  1991年   82730篇
  1990年   79953篇
  1989年   77192篇
  1988年   70490篇
  1987年   68949篇
  1986年   64477篇
  1985年   61409篇
  1984年   45651篇
  1983年   38538篇
  1982年   22881篇
  1981年   20364篇
  1979年   39802篇
  1978年   28047篇
  1977年   23764篇
  1976年   21965篇
  1975年   23510篇
  1974年   27508篇
  1973年   26032篇
  1972年   24413篇
  1971年   22613篇
  1970年   20758篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
71.
72.
Neu-Laxova syndrome (NLS) is a rare autosomal recessive syndrome, characterized by severe intrauterine growth retardation (IUGR), microcephaly, abnormal brain development, oedema and ichthyosis. It was first reported in 1971 by Neu et al. (Pediatrics 47: 610-612) and since then no more than 60 cases have been reported. A newborn girl delivered from a 29-year-old healthy mother was admitted to hospital with a thick membrane covering her body and dismorphic appearance. The diagnosis of NLS was made according to characteristic features. The syndrome is known to have a poor prognosis and the baby lived for 9 weeks. This case is one of the longest living cases of NLS and the fourth case reported from Turkey.  相似文献   
73.
The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.  相似文献   
74.
75.
76.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
77.
78.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
79.
80.
Bifid mandibular canal.   总被引:1,自引:0,他引:1  
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women.  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