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   1418453篇
  免费   113998篇
  国内免费   3388篇
耳鼻咽喉   18421篇
儿科学   46721篇
妇产科学   41162篇
基础医学   201464篇
口腔科学   37859篇
临床医学   126701篇
内科学   286364篇
皮肤病学   33432篇
神经病学   117880篇
特种医学   54091篇
外国民族医学   464篇
外科学   211927篇
综合类   32773篇
现状与发展   3篇
一般理论   488篇
预防医学   110311篇
眼科学   31689篇
药学   98905篇
  1篇
中国医学   3360篇
肿瘤学   81823篇
  2021年   11219篇
  2019年   11936篇
  2018年   16859篇
  2017年   12887篇
  2016年   14510篇
  2015年   16268篇
  2014年   22938篇
  2013年   33835篇
  2012年   46075篇
  2011年   48556篇
  2010年   28489篇
  2009年   27384篇
  2008年   44795篇
  2007年   47298篇
  2006年   47872篇
  2005年   46245篇
  2004年   44107篇
  2003年   42012篇
  2002年   40457篇
  2001年   73037篇
  2000年   74559篇
  1999年   61595篇
  1998年   17022篇
  1997年   15466篇
  1996年   15627篇
  1995年   14813篇
  1994年   13420篇
  1993年   12605篇
  1992年   45867篇
  1991年   43502篇
  1990年   41501篇
  1989年   39573篇
  1988年   36189篇
  1987年   35360篇
  1986年   32877篇
  1985年   31286篇
  1984年   23847篇
  1983年   20036篇
  1982年   12220篇
  1981年   10792篇
  1979年   20712篇
  1978年   14580篇
  1977年   12088篇
  1976年   11367篇
  1975年   11624篇
  1974年   13992篇
  1973年   13538篇
  1972年   12636篇
  1971年   11469篇
  1970年   10912篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
64.
65.
66.
67.
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   
68.
69.
背景:针对糖尿病患者Lp(a)水平和冠状动脉疾病(CAD)严重程度之间关系的研究较少并且结论有争议。另外,目前尚无关于apo(a)多态性与上述疾病关系的研究。本研究旨在探讨大样本2型糖尿病患者中冠状动脉粥样硬化的程度与Lp(a)水平及apo(a)多态性的相关性。方法:连续选取227例2型糖  相似文献   
70.
Continual loading and articulation cycles undergone by metallic (e.g., titanium) alloy arthroplasty prostheses lead to liberation of a large number of metallic debris particulates, which have long been implicated as a primary cause of periprosthetic osteolysis and postarthroplasty aseptic implant loosening. Long-term stability of total joint replacement prostheses relies on proper integration between implant biomaterial and osseous tissue, and factors that interfere with this integration are likely to cause osteolysis. Because multipotent mesenchymal stem cells (MSCs) located adjacent to the implant have an osteoprogenitor function and are critical contributors to osseous tissue integrity, when their functions or activities are compromised, osteolysis will most likely occur. To date, it is not certain or sufficiently confirmed whether MSCs endocytose titanium particles, and if so, whether particulate endocytosis has any effect on cellular responses to wear debris. This study seeks to clarify the phenomenon of titanium endocytosis by human MSCs (hMSCs), and investigates the influence of endocytosis on their activities. hMSCs incubated with commercially pure titanium particles exhibited internalized particles, as observed by scanning electron microscopy and confocal laser scanning microscopy, with time-dependent reduction in the number of extracellular particles. Particulate endocytosis was associated with reduced rates of cellular proliferation and cell-substrate adhesion, suppressed osteogenic differentiation, and increased rate of apoptosis. These cellular effects of exposure to titanium particles were reduced when endocytosis was inhibited by treatment with cytochalasin D, and no significant effect was seen when hMSCs were treated only with conditioned medium obtained from particulate-treated cells. These findings strongly suggest that the biological responses of hMSCs to wear debris are triggered primarily by the direct endocytosis of titanium particulates, and not mediated by secreted soluble factors. In this manner, therapeutical approaches that suppress particle endocytosis could reduce the bioreactivity of hMSCs to particulates, and enhance long-term orthopedic implant prognosis by minimizing wear-debris periprosthethic osteolysis.  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