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   79篇
  免费   0篇
化学   53篇
力学   6篇
数学   12篇
物理学   8篇
  2023年   1篇
  2022年   1篇
  2021年   7篇
  2020年   1篇
  2019年   3篇
  2018年   1篇
  2017年   4篇
  2016年   2篇
  2014年   1篇
  2013年   2篇
  2012年   9篇
  2011年   5篇
  2010年   4篇
  2009年   1篇
  2008年   5篇
  2007年   2篇
  2006年   5篇
  2005年   3篇
  2004年   2篇
  2003年   4篇
  2002年   3篇
  2001年   3篇
  2000年   1篇
  1995年   2篇
  1991年   1篇
  1990年   2篇
  1978年   1篇
  1973年   1篇
  1970年   1篇
  1967年   1篇
排序方式: 共有79条查询结果,搜索用时 31 毫秒
51.
A number of framework amides with a ginsenol backbone have been synthesized using the Ritter reaction. We named the acetamide as Ginsamide. A method was developed for the synthesis of the corresponding amine and thioacetamide. The new compounds revealed a high activity against H1N1 influenza, which was confirmed using an animal model. Biological experiments were performed to determine the mechanism of action of the new agents, a ginsamide-resistant strain of influenza virus was obtained, and the pathogenicity of the resistant strain and the control strain was studied. It was shown that the emergence of resistance to Ginsamide was accompanied by a reduction in the pathogenicity of the influenza virus.  相似文献   
52.
The effect of the synthesis conditions of aqueous dispersions of oxygen-containing lanthanum compounds on the size, shape, and phase composition of nanoparticles is studied. It is established that the hydrolysis of lanthanum nitrate at the boiling point of a solution affords sols with a narrower particle size distribution and a higher degree of particle crystallinity. The ranges of [OH?]/[La3+] concentration ratios are determined within which aggregatively stable aqueous dispersions of oxygen-containing lanthanum compounds can be synthesized.  相似文献   
53.
We study the groups for which the derived subgroups of all proper subgroups are Chernikov subgroups under condition that they possess a normal system whose factors are locally graduated.  相似文献   
54.
Effect of the component concentration of an orthophosphate-tetraborate aqueous electrolyte on the thickness, composition, surface structure, and protective properties of coatings deposited from this electrolyte was studied.  相似文献   
55.
56.
The thermoelastic bending of a circular light-core sandwich plate on a deformable foundation is examined. To describe the kinematics of the plate with asymmetric thickness, the hypothesis of broken normal is adopted. The reaction of the foundation is described by Winkler’s model. The thermomechanical load is local and symmetric. The system of equilibrium equations is derived and solved exactly. Numerical results for three-layer metal-polymer plate are presented __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 2, pp. 96–103, February 2006.  相似文献   
57.
Blends of linear polyurethane and poly(methyl methacrylate) were obtained in situ in the course of simultaneously proceeding reactions of polymerization and polyaddition. The effect of filler nanoparticles on the thermodynamic properties of the systems was investigated. Introduction of filler into the monomer mixture before curing increases the compatibility of final systems, as follows from diminishing thermodynamic interaction parameters. The reverse correlation has been established between the interaction parameter and the fraction of an interfacial region between two phases, its origin being the result of incomplete phase separation. Introducing filler into the reaction system determines simultaneously the increasing compatibility and increasing fraction of an interfacial region, i.e., prevents phase separation. Both effects are due to increasing of the interaction between two polymeric components at the interface with solid and changing conditions of incomplete phase separation in the course of reaction.  相似文献   
58.
Structural and phase transformations in the course of the multistage physical aging of semi-inter-penetrating polymer networks based on crosslinked polyurethane and linear polystyrene are studied. Dynamic mechanical and thermophysical studies make it possible to assume that, as a result of the physical aging, a heterogeneous polymer system experiences structural rearrangements and the fraction of the inter-facial region increases.  相似文献   
59.
Stable aqueous electrolyte emulsions with negatively charged micelles containing dispersed particles of polytetrafluoroethylene (PTFE) or graphite are obtained using siloxane-acrylate emulsion as an emulsifier. The oxide coatings formed in such electrolytes contain carbon, polytetrafluoroethylene, or graphite. The coatings with PTFE particles are similar to monolithic polytetrafluoroethylene with respect to its hydrophobic characteristics. According to X-ray photoelectron spectroscopy data, the surface of the formed coatings predominantly contains aliphatic carbon (C-C and C-H bonds) and some fraction of oxidized (or, in the case of PTFE-containing electrolytes, fluorinated) carbon.  相似文献   
60.
The transformations of 6,7-epoxy derivatives of widely spread in the nature unsaturated aldehydes, citral and citronellal, in various acidic media both under conditions of homogeneous and heterogeneous catalysis were investigated. A number of previously unknown products belonging to different classes of organic compounds was obtained. Probable mechanisms of the products formation are discussed.  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