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   2614368篇
  免费   186976篇
  国内免费   7668篇
耳鼻咽喉   34503篇
儿科学   85968篇
妇产科学   72119篇
基础医学   366862篇
口腔科学   70155篇
临床医学   237220篇
内科学   521424篇
皮肤病学   62869篇
神经病学   216209篇
特种医学   100704篇
外国民族医学   737篇
外科学   390236篇
综合类   50815篇
现状与发展   5篇
一般理论   994篇
预防医学   198548篇
眼科学   57336篇
药学   189972篇
  9篇
中国医学   5376篇
肿瘤学   146951篇
  2021年   20484篇
  2019年   21130篇
  2018年   29855篇
  2017年   23041篇
  2016年   26704篇
  2015年   30108篇
  2014年   41265篇
  2013年   61623篇
  2012年   81941篇
  2011年   86462篇
  2010年   52107篇
  2009年   50158篇
  2008年   80692篇
  2007年   85715篇
  2006年   87343篇
  2005年   83617篇
  2004年   80415篇
  2003年   77639篇
  2002年   74871篇
  2001年   128647篇
  2000年   131503篇
  1999年   110770篇
  1998年   31581篇
  1997年   28164篇
  1996年   28462篇
  1995年   27576篇
  1994年   25250篇
  1993年   23626篇
  1992年   85325篇
  1991年   81715篇
  1990年   78899篇
  1989年   76168篇
  1988年   69592篇
  1987年   68098篇
  1986年   63617篇
  1985年   60630篇
  1984年   45107篇
  1983年   38090篇
  1982年   22639篇
  1981年   20181篇
  1979年   39053篇
  1978年   27547篇
  1977年   23351篇
  1976年   21583篇
  1975年   22866篇
  1974年   26863篇
  1973年   25428篇
  1972年   23807篇
  1971年   22002篇
  1970年   20212篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
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   
72.
73.
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   
74.
BACKGROUND: The 1997 National Asthma Education and Prevention Program (NAEPP) recommends a severity classification scheme to optimize the use of anti-inflammatory therapy for persistent asthma. Physician documentation of asthma severity is often used as a quality assurance measure. OBJECTIVE: To test the hypothesis that physician documentation of asthma severity is associated with appropriate use of anti-inflammatory therapy. DESIGN/METHODS: Setting: inner-city academic health center. First, we reviewed a consecutive sample of charts of scheduled pediatric patients. Then, we administered a structured parent survey regarding the child's asthma symptoms and current asthma therapy. We used NAEPP guidelines to classify patients' severity of asthma. The main outcome measure was appropriate use of anti-inflammatory therapy. Appropriate therapy was defined as: (1) mild persistent asthmatics using anti-inflammatory therapy, and (2) moderate-severe persistent asthmatics using inhaled steroids. Chart classification of asthma severity was compared with the NAEPP-applied classification. RESULTS: Of 784 charts, 214 (27%) were asthmatic. Of these, 176 (82%) were surveyed. The mean age was 7.4 years; 61% were males. Severity classification was documented in 77% of charts. Chart documentation differed significantly from survey classification for the same patients: (mild intermittent 54% vs. 40%, mild persistent 21% vs. 14%, moderate persistent 24% vs. 36%, severe persistent 1% vs. 10%; all p < .001). Correctly classified patients were more likely to be on appropriate therapy. CONCLUSIONS: Physicians underestimated the severity classification of asthmatic patients. Incorrect classification was associated with inappropriate asthma therapy. These findings have implications for the institution of asthma quality improvement programs.  相似文献   
75.
76.
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   
77.
78.
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