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   139篇
  免费   4篇
化学   110篇
晶体学   5篇
力学   3篇
数学   9篇
物理学   16篇
  2023年   3篇
  2022年   3篇
  2021年   2篇
  2020年   3篇
  2019年   6篇
  2018年   3篇
  2017年   1篇
  2016年   6篇
  2015年   5篇
  2014年   4篇
  2013年   8篇
  2012年   7篇
  2011年   8篇
  2010年   12篇
  2009年   5篇
  2008年   4篇
  2007年   11篇
  2006年   6篇
  2005年   5篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  2000年   2篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1995年   1篇
  1993年   2篇
  1992年   5篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
  1974年   2篇
  1972年   1篇
排序方式: 共有143条查询结果,搜索用时 531 毫秒
91.
92.
Journal of Solid State Electrochemistry - In the present investigation, we have synthesized Ni3V2O8@GO composite by co-precipitation method and designed as a new anode material for supercapacitor...  相似文献   
93.
The synthesis of α-aminonitriles by a direct three component Strecker reaction has been achieved in water, which is found to be an inexpensive, non-toxic and eco-friendly reaction medium for the nucleophilic addition. This protocol is effective to a wide variety of substrates with different functional groups and does not require the use any other catalyst.  相似文献   
94.
Kinetics of reduction of the surfactant complex ions, cis‐chloro/bromo (dodecylamine)bis(ethylenediamine)cobalt(III) by iron(II) in aqueous solution was studied at 303, 308, and 313 K by spectrophotometry method under pseudo‐first‐order conditions, using an excess of the reductant. The second‐order rate constant remains constant below critical micelle concentration (cmc), but increases with cobalt(III) concentration above cmc, and the presence of aggregation of the complex itself alters the reaction rate. The rate of reaction was not affected by the added [H+]. Variation of ionic strength (μ) influences the reaction rate. Activation and thermodynamic parameters have been computed. It is suggested that the reaction of Fe2+ (aq) with cobalt(III) complex proceeds by the inner‐sphere mechanism. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: 98–105, 2006  相似文献   
95.
    
Studies on the luminescence quenching of Ru(phen)32+ (phen = 1,10-phenanthroline) by the polymer-cobalt(III) complex ions, cis-[Co(phen)2(BPEI)Cl]2+ and cis-[Co(bpy)2(BPEI)Cl]2+ (bpy = 2,2′-bipyridine, BPEI = branched polyethyleneimine) in DNA as well as in various micellar media by steady-state emission spectroscopic technique have been reported. The quenching rate constants were arrived through Stern-Volmer equation. The results have been analysed based on hydrophobic as well as electrostatic binding between polymer-cobalt(III) complexes and DNA/micelles.  相似文献   
96.
97.
Magneto–exciton bound donor is investigated in a strained InAs/InP quantum wire within the framework of single band effective mass approximation. The strain contribution to the potential is determined via deformation potential theory. The interband optical transition is computed with the various structural parameters in the influence of magnetic field.  相似文献   
98.
The generation of proteins, especially enzymes, with pre-deliberated, novel properties is a big challenge in the field of protein engineering. This aim, over the years was critically facilitated by newly emerging methods of combinatorial and evolutionary techniques, such as combinatorial gene synthesis followed by functional screening of many structural variants generated in parallel (library). Libraries can be generated by a large number of available methods. Therein the use of mixtures of pre-formed trinucleotide blocks representing codons for the 20 canonical amino acids for oligonucleotide synthesis stands out as allowing fully controlled partial (or total) randomization individually at any number of arbitrarily chosen codon positions of a given gene. This has created substantial demand of fully protected trinucleotide synthons of good reactivity in standard oligonucleotide synthesis. We here review methods for the preparation of oligonucleotide mixtures with a strong focus on codon-specific trinucleotide blocks.  相似文献   
99.
A new water-soluble surfactant copper(II) complex [Cu(sal-ala)(phen)(DA)] (sal-ala = salicylalanine, phen = 1,10-phenanthroline, DA = dodecylamine), has been synthesized and characterized by physico-chemical and spectroscopic methods. The critical micelle concentration (CMC) values of this surfactant–copper(II) complex in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308, 313. 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG0m, ΔH0m and ΔS0m). The interaction of this complex with nucleic acids (DNA and RNA) has been explored by using electronic absorption spectral titration, competitive binding experiment, cyclic voltammetry, circular dichroism (CD) spectra, and viscosity measurements. Electronic absorption studies have revealed that the complex can bind to nucleic acids by the intercalative binding mode which has been verified by viscosity measurements. The DNA binding constants have also been calculated (Kb?=?1.2?×?105 M?1 for DNA and Kb?=?1.6?×?105 M?1 for RNA). Competitive binding study with ethidium bromide (EB) showed that the complex exhibits the ability to displace the DNA-bound-EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. The presence of hydrophobic ligands, alanine Schiff-base, phenanthroline and long aliphatic chain amine in the complex were responsible for this strong intercalative binding. The surfactant–copper (II) complex was screened for its antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, amikacin(antibacterial) and ketokonazole(antifungal).  相似文献   
100.
Unsteady laminar flow of a dusty viscous, incompressible fluid through a cylindrical tube of triangular cross-section is considered in two cases: (i) when the pressure gradient varies harmonically with time and (ii) when it varies exponentially. The velocity fields for the fluid and dust particles have been determined. Flux and skin-friction drag on the walls of the cylinder have been calculated and particular cases 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