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   226篇
  免费   3篇
化学   141篇
晶体学   2篇
力学   7篇
数学   47篇
物理学   32篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   6篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2016年   4篇
  2015年   1篇
  2013年   19篇
  2012年   9篇
  2011年   14篇
  2010年   7篇
  2009年   6篇
  2008年   4篇
  2007年   8篇
  2006年   9篇
  2005年   12篇
  2004年   10篇
  2003年   15篇
  2002年   9篇
  2001年   4篇
  2000年   6篇
  1999年   3篇
  1998年   5篇
  1996年   5篇
  1995年   6篇
  1994年   3篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   5篇
  1987年   1篇
  1986年   3篇
  1985年   8篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1980年   4篇
  1979年   2篇
  1978年   4篇
  1977年   4篇
  1976年   4篇
  1974年   2篇
  1973年   3篇
  1969年   1篇
  1935年   2篇
排序方式: 共有229条查询结果,搜索用时 15 毫秒
111.
We study the behaviour near the boundary angular or conical point of weak solutions to the Robin problem for elliptic quasi-linear second-order equation with the p-Laplacian.  相似文献   
112.
Trimethylsilyl ethylene oxide and other α,β-epoxysilanes were obtained from corresponding (trimethylsilyl)alkenes by an one-pot procedure involving successive treatment with N-bromosuccinimide and aqueous sodium hydroxide.  相似文献   
113.
Organothiol monolayers on metal substrates (Au, Ag, Cu) and their use in a wide variety of applications have been extensively studied. Here, the growth of layers of organothiols directly onto muscovite mica is demonstrated using a simple procedure. Atomic force microscopy, surface X‐ray diffraction, and vibrational sum‐frequency generation IR spectroscopy studies revealed that organothiols with various functional endgroups could be self‐assembled into (water) stable and adaptable ultra‐flat organothiol monolayers over homogenous areas as large as 1 cm2. The strength of the mica–organothiol interactions could be tuned by exchanging the potassium surface ions for copper ions. Several of these organothiol monolayers were subsequently used as a template for calcite growth.  相似文献   
114.
The complete assignments of twelve 4-aryl-7-thioaryl-1,5-benzodiazepines 1H and 13C spectra, performed with the use of high resolution variable solvent and temperature 1D and 2D techniques (e.g. HOMOCOSY, NOESY, HMQC and HMBC), lead to the determination of conformational equilibria between two rotamers having the aromatic ring of the thioaryl oriented in a perpendicular or helical orientation toward the benzodiazepine ring. The restricted rotation was evaluated from the population of these conformers.  相似文献   
115.
In an attempt to get more insight into the links between the coverage of dynamic electron correlation effects defined in traditional wave function theories (WFT) by density functional theories (DFT) we have performed comprehensive studies for the Ar atom, for which the dynamic correlation effects play the dominant role. A density-based approach directly hinged on difference radial density (DRD) distributions defined with respect the Hartree-Fock radial density has been employed for analyzing the impact of dynamic correlation effects on the density. The DRD-distributions calculated by ab initio methods have been compared with their DFT counterparts generated for representatives of several generations of broadly used exchange-correlation functionals and for the recently developed orbital-dependent OEP2 exchange-correlation functional (Bartlett et al. in J Chem Phys 122:034104, 2005). For the local, generalized-gradient, and hybrid functionals it has been found that the dynamic WFT correlation effects on the density are to a significant extent accounted for by densities resulting from exchange-only calculations. It has been shown that the removal of self-interaction errors does not change this result. It has been demonstrated that the VWN5 and LYP correlation functionals do not represent any substantial dynamical correlation effects on the electron density, whereas these effects are well represented by the orbital-dependent OEP2 correlation functional. Critical comparison of the results of the present investigations with various published results obtained for more complex many-electron systems has been made. Attention has been paid to bringing into sharper relief the differences between the conclusions reached when using energy- or density-based criteria.  相似文献   
116.
1-Alkyl-3-methylpyridinium-based ionic liquids with substituents from C2 to C10 and anions Cl? and Br? were synthesized, and their dissolving power toward the cellulose was investigated. The results of quantum-chemical calculations of molecules of ionic liquids are presented.  相似文献   
117.
118.
The monotone iterative technique is used to boundary problems for second order ordinary differential equations with deviating arguments. Corresponding results are formulated when the problem has extremal solutions or weakly coupled extremal quasi-solutions.  相似文献   
119.
120.
This paper deals with impulsive second order differential equations with deviating arguments. We investigate the existence of solutions of such problems with nonlinear boundary conditions. To obtain corresponding results we discuss also second order impulsive differential inequalities with deviating arguments.  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