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   2797794篇
  免费   194858篇
  国内免费   8074篇
耳鼻咽喉   36926篇
儿科学   91282篇
妇产科学   76588篇
基础医学   393020篇
口腔科学   75376篇
临床医学   251895篇
内科学   561134篇
皮肤病学   68265篇
神经病学   232668篇
特种医学   105542篇
外国民族医学   836篇
外科学   413002篇
综合类   51401篇
现状与发展   5篇
一般理论   1024篇
预防医学   215899篇
眼科学   60738篇
药学   202437篇
  8篇
中国医学   5998篇
肿瘤学   156682篇
  2021年   24303篇
  2019年   25033篇
  2018年   36133篇
  2017年   27081篇
  2016年   30706篇
  2015年   34492篇
  2014年   46399篇
  2013年   69300篇
  2012年   95192篇
  2011年   99766篇
  2010年   58825篇
  2009年   55417篇
  2008年   91625篇
  2007年   97324篇
  2006年   97969篇
  2005年   94215篇
  2004年   90163篇
  2003年   86662篇
  2002年   83282篇
  2001年   131992篇
  2000年   134971篇
  1999年   113815篇
  1998年   32294篇
  1997年   28787篇
  1996年   28954篇
  1995年   28073篇
  1994年   25656篇
  1993年   23964篇
  1992年   87149篇
  1991年   83409篇
  1990年   80558篇
  1989年   77651篇
  1988年   71007篇
  1987年   69446篇
  1986年   64904篇
  1985年   61818篇
  1984年   45983篇
  1983年   38824篇
  1982年   23046篇
  1981年   20427篇
  1979年   39892篇
  1978年   28111篇
  1977年   23892篇
  1976年   22038篇
  1975年   23485篇
  1974年   27606篇
  1973年   26202篇
  1972年   24539篇
  1971年   22711篇
  1970年   20946篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
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   
82.
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   
83.
84.
85.
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   
86.
87.
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   
88.
89.
90.
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