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   2602501篇
  免费   185902篇
  国内免费   7633篇
耳鼻咽喉   34437篇
儿科学   85417篇
妇产科学   71796篇
基础医学   365567篇
口腔科学   70052篇
临床医学   235876篇
内科学   518428篇
皮肤病学   62873篇
神经病学   215157篇
特种医学   100871篇
外国民族医学   736篇
外科学   389279篇
综合类   50471篇
现状与发展   5篇
一般理论   973篇
预防医学   196699篇
眼科学   56833篇
药学   188926篇
  8篇
中国医学   5344篇
肿瘤学   146288篇
  2021年   20387篇
  2019年   20975篇
  2018年   29709篇
  2017年   22931篇
  2016年   26628篇
  2015年   30003篇
  2014年   41054篇
  2013年   61132篇
  2012年   81415篇
  2011年   85756篇
  2010年   51793篇
  2009年   49871篇
  2008年   80088篇
  2007年   84962篇
  2006年   86586篇
  2005年   82680篇
  2004年   79579篇
  2003年   76823篇
  2002年   74033篇
  2001年   128547篇
  2000年   131435篇
  1999年   110637篇
  1998年   31381篇
  1997年   28051篇
  1996年   28290篇
  1995年   27452篇
  1994年   25121篇
  1993年   23457篇
  1992年   85197篇
  1991年   81591篇
  1990年   78814篇
  1989年   76096篇
  1988年   69493篇
  1987年   68017篇
  1986年   63571篇
  1985年   60524篇
  1984年   44952篇
  1983年   37953篇
  1982年   22462篇
  1981年   19988篇
  1979年   38966篇
  1978年   27449篇
  1977年   23256篇
  1976年   21497篇
  1975年   22820篇
  1974年   26790篇
  1973年   25372篇
  1972年   23751篇
  1971年   21958篇
  1970年   20186篇
排序方式: 共有10000条查询结果,搜索用时 15 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