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   1411669篇
  免费   113726篇
  国内免费   3334篇
耳鼻咽喉   18371篇
儿科学   46596篇
妇产科学   41077篇
基础医学   200859篇
口腔科学   37722篇
临床医学   126075篇
内科学   284694篇
皮肤病学   33368篇
神经病学   116919篇
特种医学   53840篇
外国民族医学   464篇
外科学   210694篇
综合类   32772篇
现状与发展   3篇
一般理论   487篇
预防医学   110062篇
眼科学   31543篇
药学   98621篇
  1篇
中国医学   3355篇
肿瘤学   81206篇
  2021年   10891篇
  2019年   11695篇
  2018年   16617篇
  2017年   12697篇
  2016年   14282篇
  2015年   16041篇
  2014年   22620篇
  2013年   33433篇
  2012年   45463篇
  2011年   48011篇
  2010年   28202篇
  2009年   27092篇
  2008年   44374篇
  2007年   46883篇
  2006年   47457篇
  2005年   45917篇
  2004年   43797篇
  2003年   41739篇
  2002年   40215篇
  2001年   73005篇
  2000年   74530篇
  1999年   61562篇
  1998年   17000篇
  1997年   15434篇
  1996年   15588篇
  1995年   14795篇
  1994年   13397篇
  1993年   12585篇
  1992年   45839篇
  1991年   43479篇
  1990年   41489篇
  1989年   39551篇
  1988年   36180篇
  1987年   35356篇
  1986年   32862篇
  1985年   31279篇
  1984年   23832篇
  1983年   20026篇
  1982年   12209篇
  1981年   10781篇
  1979年   20702篇
  1978年   14577篇
  1977年   12084篇
  1976年   11364篇
  1975年   11619篇
  1974年   13989篇
  1973年   13539篇
  1972年   12634篇
  1971年   11471篇
  1970年   10910篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
36.
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   
37.
38.
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   
39.
40.
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