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   2440377篇
  免费   181228篇
  国内免费   4213篇
耳鼻咽喉   34951篇
儿科学   73811篇
妇产科学   63549篇
基础医学   340859篇
口腔科学   68355篇
临床医学   220956篇
内科学   478650篇
皮肤病学   48591篇
神经病学   205917篇
特种医学   97483篇
外国民族医学   890篇
外科学   368821篇
综合类   56667篇
现状与发展   1篇
一般理论   1024篇
预防医学   194295篇
眼科学   56452篇
药学   180579篇
  63篇
中国医学   4429篇
肿瘤学   129475篇
  2018年   25789篇
  2017年   19928篇
  2016年   21810篇
  2015年   24628篇
  2014年   35394篇
  2013年   53210篇
  2012年   72119篇
  2011年   75851篇
  2010年   44432篇
  2009年   42689篇
  2008年   71675篇
  2007年   76059篇
  2006年   76819篇
  2005年   74661篇
  2004年   71691篇
  2003年   69300篇
  2002年   68251篇
  2001年   112765篇
  2000年   116781篇
  1999年   98629篇
  1998年   28272篇
  1997年   25856篇
  1996年   25720篇
  1995年   24853篇
  1994年   23364篇
  1993年   21735篇
  1992年   79534篇
  1991年   76530篇
  1990年   73676篇
  1989年   70945篇
  1988年   65945篇
  1987年   64896篇
  1986年   61421篇
  1985年   58465篇
  1984年   44319篇
  1983年   37740篇
  1982年   22972篇
  1981年   20407篇
  1979年   41339篇
  1978年   29020篇
  1977年   24391篇
  1976年   22861篇
  1975年   23987篇
  1974年   29669篇
  1973年   28077篇
  1972年   26245篇
  1971年   24168篇
  1970年   22767篇
  1969年   21110篇
  1968年   19152篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation.  相似文献   
32.
33.
34.
35.
36.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
37.
38.
39.
40.
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   
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