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   4257篇
  免费   186篇
  国内免费   17篇
化学   2852篇
晶体学   37篇
力学   103篇
数学   425篇
物理学   1043篇
  2023年   19篇
  2022年   14篇
  2021年   65篇
  2020年   82篇
  2019年   83篇
  2018年   67篇
  2017年   54篇
  2016年   134篇
  2015年   130篇
  2014年   162篇
  2013年   259篇
  2012年   352篇
  2011年   374篇
  2010年   207篇
  2009年   195篇
  2008年   288篇
  2007年   265篇
  2006年   238篇
  2005年   228篇
  2004年   169篇
  2003年   160篇
  2002年   124篇
  2001年   96篇
  2000年   73篇
  1999年   61篇
  1998年   42篇
  1997年   31篇
  1996年   47篇
  1995年   44篇
  1994年   45篇
  1993年   47篇
  1992年   32篇
  1991年   20篇
  1990年   30篇
  1989年   19篇
  1987年   9篇
  1986年   16篇
  1985年   19篇
  1984年   10篇
  1983年   8篇
  1982年   12篇
  1980年   11篇
  1978年   8篇
  1977年   8篇
  1976年   9篇
  1974年   7篇
  1973年   10篇
  1943年   8篇
  1942年   13篇
  1941年   10篇
排序方式: 共有4460条查询结果,搜索用时 62 毫秒
1.
Plasma Chemistry and Plasma Processing - CF4 is commonly used in semiconductor industries, and its removal requires a large amount of energy because it is a highly stable perfluorinated compound....  相似文献   
2.
3.
International Journal of Theoretical Physics - In this study, the momentum-kick model is used to understand the ridge behaviour in dihadron Δη–Δφ correlations recently...  相似文献   
4.
Annals of the Institute of Statistical Mathematics - The segmentation of a time series into piecewise stationary segments is an important problem both in time series analysis and signal processing....  相似文献   
5.
Abstract

To enable recent 3D and moving picture applications, liquid crystal displays (LCD) must exhibit fast response and wide viewing angle characteristics. Pre-tilted vertical alignment layers for high-speed LCD were fabricated using bi-functional photoreactive monomers. The monomers can be confined to the polyimide layer and photo-polymerized by UV exposure under voltage. Response characteristics of photo-controlled alignment films according to the structure were investigated. Vertical alignment properties were evaluated using a polarizing optical microscope, and electro-optical characteristics were compared through the voltage-transmittance curve and response time measurement. Faster response speed could be obtained by using photoreactive monomers having a long alkyl chain.  相似文献   
6.
Numerical Algorithms - In this paper, we introduce a new algorithm which combines the inertial projection and contraction method and the viscosity method for solving monotone variational inequality...  相似文献   
7.
8.
T cells are the central mediators of both humoral and cellular adaptive immune responses. Highly specific receptor-mediated clonal selection and expansion of T cells assure antigen-specific immunity. In addition, encounters with cognate antigens generate immunological memory, the capacity for long-term, antigen-specific immunity against previously encountered pathogens. However, T-cell receptor (TCR)-independent activation, termed “bystander activation”, has also been found. Bystander-activated T cells can respond rapidly and secrete effector cytokines even in the absence of antigen stimulation. Recent studies have rehighlighted the importance of antigen-independent bystander activation of CD4+ T cells in infection clearance and autoimmune pathogenesis, suggesting the existence of a distinct innate-like immunological function performed by conventional T cells. In this review, we discuss the inflammatory mediators that activate bystander CD4+ T cells and the potential physiological roles of these cells during infection, autoimmunity, and cancer.Subject terms: T cells, CD4-positive T cells  相似文献   
9.
Rosacea is a common and chronic inflammatory skin disease that is characterized by dysfunction of the immune and vascular system. The excessive production and activation of kallikerin 5 (KLK5) and cathelicidin have been implicated in the pathogenesis of rosacea. Coptis chinensis Franch (CC) has been used as a medicinal herb in traditional oriental medicine. However, little is known about the efficacy and mechanism of action of CC in rosacea. In this study, we evaluate the effect of CC and its molecular mechanism on rosacea in human epidermal keratinocytes. CC has the capacity to downregulate the expression of KLK5 and cathelicidin, and also inhibits KLK5 protease activity, which leads to reduced processing of inactive cathelicidin into active LL-37. It was determined that CC ameliorates the expression of pro-inflammatory cytokines through the inhibition of LL-37 processing. In addition, it was confirmed that chitin, an exoskeleton of Demodex mites, mediates an immune response through TLR2 activation, and CC inhibits TLR2 expression and downstream signal transduction. Furthermore, CC was shown to inhibit the proliferation of human microvascular endothelial cells induced by LL-37, the cause of erythematous rosacea. These results demonstrate that CC improved rosacea by regulating the immune response and angiogenesis, and revealed its mechanism of action, indicating that CC may be a useful therapeutic agent for rosacea.  相似文献   
10.
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