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   3271604篇
  免费   226724篇
  国内免费   8483篇
耳鼻咽喉   44961篇
儿科学   108593篇
妇产科学   90637篇
基础医学   459813篇
口腔科学   89967篇
临床医学   297116篇
内科学   636187篇
皮肤病学   78318篇
神经病学   264429篇
特种医学   126117篇
外国民族医学   918篇
外科学   487741篇
综合类   65860篇
现状与发展   6篇
一般理论   1187篇
预防医学   246647篇
眼科学   74626篇
药学   244634篇
  13篇
中国医学   7175篇
肿瘤学   181866篇
  2021年   25417篇
  2019年   25858篇
  2018年   36544篇
  2017年   28227篇
  2016年   32656篇
  2015年   36541篇
  2014年   50233篇
  2013年   74983篇
  2012年   100044篇
  2011年   105791篇
  2010年   63552篇
  2009年   60627篇
  2008年   98273篇
  2007年   104528篇
  2006年   106390篇
  2005年   101874篇
  2004年   97871篇
  2003年   94350篇
  2002年   91052篇
  2001年   159591篇
  2000年   163618篇
  1999年   137692篇
  1998年   38973篇
  1997年   34563篇
  1996年   34740篇
  1995年   33557篇
  1994年   30577篇
  1993年   28679篇
  1992年   106487篇
  1991年   102519篇
  1990年   99686篇
  1989年   96433篇
  1988年   88106篇
  1987年   86089篇
  1986年   80973篇
  1985年   77031篇
  1984年   57167篇
  1983年   48171篇
  1982年   28325篇
  1979年   50615篇
  1978年   35297篇
  1977年   30628篇
  1976年   27804篇
  1975年   30149篇
  1974年   35407篇
  1973年   33768篇
  1972年   31904篇
  1971年   29651篇
  1970年   27278篇
  1969年   26253篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
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   
82.
83.
84.
Neu-Laxova syndrome (NLS) is a rare autosomal recessive syndrome, characterized by severe intrauterine growth retardation (IUGR), microcephaly, abnormal brain development, oedema and ichthyosis. It was first reported in 1971 by Neu et al. (Pediatrics 47: 610-612) and since then no more than 60 cases have been reported. A newborn girl delivered from a 29-year-old healthy mother was admitted to hospital with a thick membrane covering her body and dismorphic appearance. The diagnosis of NLS was made according to characteristic features. The syndrome is known to have a poor prognosis and the baby lived for 9 weeks. This case is one of the longest living cases of NLS and the fourth case reported from Turkey.  相似文献   
85.
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   
86.
87.
88.
89.
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   
90.
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