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   23774篇
  免费   1222篇
  国内免费   159篇
耳鼻咽喉   210篇
儿科学   553篇
妇产科学   266篇
基础医学   3253篇
口腔科学   410篇
临床医学   1416篇
内科学   6334篇
皮肤病学   579篇
神经病学   1789篇
特种医学   976篇
外科学   4004篇
综合类   120篇
预防医学   558篇
眼科学   573篇
药学   1501篇
中国医学   40篇
肿瘤学   2573篇
  2023年   114篇
  2022年   227篇
  2021年   489篇
  2020年   275篇
  2019年   355篇
  2018年   505篇
  2017年   389篇
  2016年   473篇
  2015年   499篇
  2014年   730篇
  2013年   821篇
  2012年   1400篇
  2011年   1577篇
  2010年   883篇
  2009年   797篇
  2008年   1393篇
  2007年   1554篇
  2006年   1511篇
  2005年   1651篇
  2004年   1665篇
  2003年   1698篇
  2002年   1575篇
  2001年   298篇
  2000年   252篇
  1999年   336篇
  1998年   408篇
  1997年   328篇
  1996年   315篇
  1995年   269篇
  1994年   245篇
  1993年   222篇
  1992年   170篇
  1991年   155篇
  1990年   140篇
  1989年   123篇
  1988年   130篇
  1987年   103篇
  1986年   111篇
  1985年   104篇
  1984年   107篇
  1983年   80篇
  1982年   76篇
  1981年   79篇
  1980年   70篇
  1979年   62篇
  1978年   50篇
  1977年   50篇
  1976年   40篇
  1975年   34篇
  1972年   28篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
951.
952.
Anemia, a frequently occurring condition in older patients, has no standard definition; however, in most studies, it is defined as hemoglobin level <12 and <13 g/dL in women and men, respectively. Approximately 10% of older adults living in the community have anemia. The prevalence of anemia is significantly correlated with advanced age and male sex. Anemia is associated with falls, frailty and other negative outcomes, including early mortality. However, there remains little consensus regarding whether anemia treatment favorably affects these adverse outcomes. Therefore, this article reviews the prevalence of anemia, and provides updates on its common causes and treatments in older adults. While excluding well-established hematopoietic diseases, the etiology of anemia in older adults has been grouped into four categories: (i) nutritional deficiency; (ii) inflammation; (iii) clonal hematopoiesis; and (iv) “unexplained anemia,” when there is no clear mechanism to account for the anemia. Recently, clonal leukocytes were detected in a considerable number of older individuals. The number of somatic mutations in blood leukocytes increases with age; however, single mutations of DNMT3A, TET2 and ASXL1 are not correlated with the presence of unexplained anemia in older adults. With an increased understanding of anemia etiology and the availability of innovative anti-anemic drugs, future studies that evaluate the causes and benefits of treatment are required. Geriatr Gerontol Int 2021; 21: 549–554 .  相似文献   
953.
954.
955.
956.
ObjectivesTo investigate the frequency of imatinib-induced pancreatic complications and determine whether these are survival prognostic factors in patients with gastrointestinal stromal tumor (GIST).MethodsThis retrospective multicenter study included patients with histopathologically diagnosed GIST treated with imatinib who underwent computed tomography (CT) within 100 days before (pretreatment CT) and 500 days after (post-treatment CT) imatinib initiation (January 2004–December 2019). Forty-eight patients (63.0 ± 12.1 years, 30 men) were included. Two blinded radiologists independently measured pancreatic volumes. Pancreatic volume on pretreatment CT was compared with that of the control (within 1 year prior to pretreatment CT) and the first two post-treatment CTs using paired t-tests. Thresholds for pancreatic hypertrophy and atrophy were defined using a log-rank test. The prognostic importance of pancreatic hypertrophy was further analyzed using multivariate Cox proportional hazard regression models.ResultsPancreatic volume was significantly higher for the first post-treatment CT than pretreatment CT (71.5 cm3 vs. 67.4 cm3, P = .027), whereas no significant difference was observed between the pretreatment and control CTs. Optimal thresholds for pancreatic hypertrophy and atrophy were defined as an 22% increase and 30% decrease and found in 20 and three patients, respectively. Pancreatic hypertrophy was significantly associated with reduced survival [hazard ratio = 2.9 (95% confidence interval, 1.3–6.5), P = .0088]. No patients showed serum lipase elevation, nor were they suspected of having acute pancreatitis.ConclusionThere was frequent asymptomatic pancreatic swelling in patients with GIST after imatinib treatment, and a ≥22% increase in pancreatic volume was a predictor of reduced survival.  相似文献   
957.
958.
959.
960.
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