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   3419867篇
  免费   244292篇
  国内免费   10839篇
耳鼻咽喉   45620篇
儿科学   112258篇
妇产科学   94518篇
基础医学   484267篇
口腔科学   94402篇
临床医学   320249篇
内科学   665878篇
皮肤病学   78162篇
神经病学   283312篇
特种医学   129142篇
外国民族医学   1047篇
外科学   499722篇
综合类   71989篇
现状与发展   6篇
一般理论   1343篇
预防医学   272658篇
眼科学   76596篇
药学   250172篇
  12篇
中国医学   7489篇
肿瘤学   186156篇
  2019年   27699篇
  2018年   38927篇
  2017年   29700篇
  2016年   33938篇
  2015年   38336篇
  2014年   52840篇
  2013年   80522篇
  2012年   107635篇
  2011年   113950篇
  2010年   68341篇
  2009年   64718篇
  2008年   105860篇
  2007年   112104篇
  2006年   113743篇
  2005年   109201篇
  2004年   104748篇
  2003年   100964篇
  2002年   97609篇
  2001年   159216篇
  2000年   163434篇
  1999年   137988篇
  1998年   40286篇
  1997年   35778篇
  1996年   35767篇
  1995年   34522篇
  1994年   31866篇
  1993年   29967篇
  1992年   108336篇
  1991年   104759篇
  1990年   101581篇
  1989年   97742篇
  1988年   89790篇
  1987年   88062篇
  1986年   83044篇
  1985年   79347篇
  1984年   59337篇
  1983年   50657篇
  1982年   30179篇
  1981年   26907篇
  1979年   52952篇
  1978年   37606篇
  1977年   31537篇
  1976年   29790篇
  1975年   31370篇
  1974年   37430篇
  1973年   35841篇
  1972年   33489篇
  1971年   31155篇
  1970年   28846篇
  1969年   27305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