首页 | 官方网站   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   5650篇
  免费   95篇
  国内免费   8篇
工业技术   5753篇
  2021年   32篇
  2019年   27篇
  2018年   41篇
  2017年   28篇
  2016年   37篇
  2015年   41篇
  2014年   70篇
  2013年   163篇
  2012年   106篇
  2011年   106篇
  2010年   113篇
  2009年   128篇
  2008年   136篇
  2007年   124篇
  2006年   105篇
  2005年   101篇
  2004年   93篇
  2003年   107篇
  2002年   76篇
  2001年   92篇
  2000年   114篇
  1999年   146篇
  1998年   741篇
  1997年   473篇
  1996年   311篇
  1995年   238篇
  1994年   181篇
  1993年   199篇
  1992年   65篇
  1991年   89篇
  1990年   107篇
  1989年   106篇
  1988年   76篇
  1987年   86篇
  1986年   60篇
  1985年   74篇
  1984年   68篇
  1983年   62篇
  1982年   52篇
  1981年   67篇
  1980年   53篇
  1979年   42篇
  1978年   31篇
  1977年   99篇
  1976年   153篇
  1975年   37篇
  1974年   37篇
  1973年   45篇
  1972年   23篇
  1970年   24篇
排序方式: 共有5753条查询结果,搜索用时 62 毫秒
1.
A study using three different pairs of electrochromic polymers (ECPs) synthesized onto plaques by means of a modified vapor phase polymerization (VPP) technique is presented. Restriction of the respective polymerization times, allowed both faster and slower polymerizing monomers to be controlled, and produced blended plaques with visually diffuse interfaces. The ECPs within the blended plaques retain their individual electrochromic behavior and when encapsulated into an electrochromic device, show outstanding optical switching performance with little degradation evident over 10,000 cycles, coupled with a switching time of the order of 1 second. Blends also allow multiple diffuse color changes within an electrochromic device, due to the difference in oxidation potentials of the individual ECPs, making them candidates for adaptive camouflage use. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42158.  相似文献   
2.
3.
Mincle agonists have been shown to induce inflammatory cytokine production, such as tumor necrosis factor-alpha (TNF) and promote the development of a Th1/Th17 immune response that might be crucial to development of effective vaccination against pathogens such as Mycobacterium tuberculosis. As an expansion of our previous work, a library of 6,6′-amide and sulfonamide α,α-d -trehalose compounds with various substituents on the aromatic ring was synthesized efficiently in good to excellent yields. These compounds were evaluated for their ability to activate the human C-type lectin receptor Mincle by the induction of cytokines from human peripheral blood mononuclear cells. A preliminary structure–activity relationship (SAR) of these novel trehalose diamides and sulfonamides revealed that aryl amide-linked trehalose compounds demonstrated improved activity and relatively high potency cytokine production compared to the Mincle ligand trehalose dibehenate adjuvant (TDB) and the natural ligand trehalose dimycolate (TDM) inducing dose-dependent and human-Mincle-specific stimulation in a HEK reporter cell line.  相似文献   
4.
This paper describes the methodology for simulating a reprographic ink with a ceramic ink based on a commercially available zirconia powder for direct ceramic ink-jet printing. Of over-riding importance was matching viscosity and this was tested systematically by using a mineral oil–hexane binary system. Of secondary importance was adjustment of the pressure defect behind the nozzle to compensate for small differences in surface tension. The inks tested in the wide array print-head were based on low electrical conductivity liquids to avoid damage to the electroding system. The organic binder for the zirconia ink was paraffin wax and the dispersant was a hydroxystearic acid based polyester.  相似文献   
5.
6.
7.
Composite flooring systems incorporating cold formed profiled steel sheeting as both permanent formwork and tensile reinforcement are becoming widely adopted for high rise buildings. Research has shown that the performance of the sheeting alone in supporting the weight of wet concrete during construction frequently governs the design. This paper concentrates upon this aspect of the behaviour and describes the application of the elasticity method, derived from folded plate analysis. The method allows the important deformations due to ponding and transverse bending to be taken into account accurately; such deformations are treated empirically, or ignored, in current design codes. Comparisons with the summarised results of many tests establish the accuracy of the folded plate method and indicate the limitations of the codes. Folded plate analysis is also used to illustrate several aspects of behaviour, particularly the possible movements at the lapped joints between adjacent sheets.  相似文献   
8.
9.
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-23

京公网安备 11010802026262号