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   2592376篇
  免费   185415篇
  国内免费   7577篇
耳鼻咽喉   34329篇
儿科学   85432篇
妇产科学   71688篇
基础医学   364209篇
口腔科学   69830篇
临床医学   235226篇
内科学   516274篇
皮肤病学   62524篇
神经病学   213888篇
特种医学   99977篇
外国民族医学   739篇
外科学   386907篇
综合类   50460篇
现状与发展   5篇
一般理论   979篇
预防医学   197021篇
眼科学   56713篇
药学   188275篇
  8篇
中国医学   5336篇
肿瘤学   145548篇
  2021年   20149篇
  2019年   20782篇
  2018年   29446篇
  2017年   22711篇
  2016年   26336篇
  2015年   29615篇
  2014年   40635篇
  2013年   60718篇
  2012年   80604篇
  2011年   84865篇
  2010年   51179篇
  2009年   49326篇
  2008年   79310篇
  2007年   84161篇
  2006年   85868篇
  2005年   82046篇
  2004年   78981篇
  2003年   76259篇
  2002年   73513篇
  2001年   128459篇
  2000年   131390篇
  1999年   110539篇
  1998年   31282篇
  1997年   27943篇
  1996年   28232篇
  1995年   27404篇
  1994年   25080篇
  1993年   23425篇
  1992年   85185篇
  1991年   81585篇
  1990年   78809篇
  1989年   76092篇
  1988年   69489篇
  1987年   68016篇
  1986年   63573篇
  1985年   60531篇
  1984年   44956篇
  1983年   37956篇
  1982年   22470篇
  1981年   19997篇
  1979年   38985篇
  1978年   27461篇
  1977年   23283篇
  1976年   21511篇
  1975年   22827篇
  1974年   26803篇
  1973年   25389篇
  1972年   23780篇
  1971年   21967篇
  1970年   20210篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
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   
72.
73.
74.
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   
75.
76.
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   
77.
78.
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   
79.
80.
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