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   3432632篇
  免费   245664篇
  国内免费   10827篇
耳鼻咽喉   45866篇
儿科学   112550篇
妇产科学   94637篇
基础医学   485862篇
口腔科学   94785篇
临床医学   321751篇
内科学   668436篇
皮肤病学   78269篇
神经病学   284481篇
特种医学   129480篇
外国民族医学   1047篇
外科学   501306篇
综合类   72395篇
现状与发展   6篇
一般理论   1367篇
预防医学   274121篇
眼科学   76997篇
药学   250981篇
  77篇
中国医学   7529篇
肿瘤学   187180篇
  2021年   27405篇
  2019年   27841篇
  2018年   39081篇
  2017年   29833篇
  2016年   34117篇
  2015年   38492篇
  2014年   53053篇
  2013年   80806篇
  2012年   108069篇
  2011年   114352篇
  2010年   68556篇
  2009年   64935篇
  2008年   106236篇
  2007年   112513篇
  2006年   114164篇
  2005年   109622篇
  2004年   105126篇
  2003年   101368篇
  2002年   97958篇
  2001年   159448篇
  2000年   163641篇
  1999年   138176篇
  1998年   40378篇
  1997年   35876篇
  1996年   35888篇
  1995年   34612篇
  1994年   31970篇
  1993年   30051篇
  1992年   108519篇
  1991年   104935篇
  1990年   101749篇
  1989年   97895篇
  1988年   89931篇
  1987年   88195篇
  1986年   83200篇
  1985年   79511篇
  1984年   59485篇
  1983年   50763篇
  1982年   30284篇
  1979年   53115篇
  1978年   37733篇
  1977年   31631篇
  1976年   29870篇
  1975年   31477篇
  1974年   37548篇
  1973年   35936篇
  1972年   33597篇
  1971年   31252篇
  1970年   28924篇
  1969年   27394篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
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   
102.
103.
104.
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   
105.
106.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
107.
108.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  相似文献   
109.
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   
110.
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