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   83篇
  免费   1篇
  国内免费   3篇
化学   45篇
晶体学   2篇
力学   6篇
数学   24篇
物理学   10篇
  2022年   2篇
  2021年   2篇
  2020年   3篇
  2019年   6篇
  2018年   3篇
  2017年   3篇
  2016年   2篇
  2015年   1篇
  2014年   1篇
  2013年   5篇
  2012年   8篇
  2011年   11篇
  2010年   3篇
  2009年   3篇
  2008年   6篇
  2007年   4篇
  2006年   3篇
  2005年   4篇
  2004年   1篇
  2003年   5篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1998年   2篇
  1997年   1篇
  1994年   1篇
  1989年   1篇
排序方式: 共有87条查询结果,搜索用时 31 毫秒
51.
We present in this paper a consistent nonparametric test for heteroscedasticity when data are of functional kind. The latter is constructed by evaluating the difference between the conditional and unconditional variances. We show the asymptotic normality of the statistical test under the null hypothesis. In addition, we prove that this test is consistent against all deviations from homoscedasticity condition.  相似文献   
52.
Multiconfiguration self-consistent field and multiconfiguration reference interaction including the Davidson’s correction techniques were employed to calculate the potential energy curves (PECs) of the BeS/BeS+ electronic states correlating to the 4/5 lowest dissociation limits. After nuclear motion treatment, we deduced reliable spectroscopic data for the neutral and cationic bound states. For BeS, the transition moments and spin-orbit couplings were also evaluated and used later with the PECs to deduce the rovibronic transition probabilities and the radiative lifetimes in the low-lying states, and to investigate the unimolecular decomposition processes of BeS (X1Σ+, A1Π, 3Σ+ and B1Σ+) leading to Be(1Sg) + S(3Pg). The prominent mechanism is a spin-orbit induced predissociation via the repulsive BeS(13Σ) state. Finally, we give the single ionization spectrum of BeS (X1Σ+) populating the BeS+ (X2Π, 12Σ, 12Σ+, 12Δ, 22Σ+, 22Π and 32Π) electronic states. The adiabatic ionisation energy of BeS is estimated to be ∼9.15 eV.  相似文献   
53.
It is shown that in blends of PE having different melting temperatures the morphology depends drastically on the cooling rate. In these heterogeneous PE, the correlation relationship L = r between the long period L of the solid state and the dimension of the coils r in the liquid state is observed only in rapidly quenched materials. In slowcooled materials the SAXS spectra are interpreted in terms of segregation of two types of PE, on a scale of the order of the dimension of the coils, the arrangement of the crystalline lamellae being paracrystalline and statistical.  相似文献   
54.
This Note deals with the identification of internal planar cracks inside a three-dimensional elastic body via two approaches relying on domain decomposition using elastostatic measurements. These approaches consist in recasting the problem in terms of primal or dual Steklov–Poincaré equations. The primal approach is a straightforward continuation to the elastic Cauchy problem of the work presented in J. Ben Abdallah (2007) [1] which is devoted to the Cauchy problem for the scalar Laplace equation. The numerical performances of these formulations are compared.  相似文献   
55.
First are given results on the norm-continuity of translation semigroups and their asymptotic behavior. Secondly a cell cycle model is studied from the point of view of linear translation semigroups theory. Existence and norm-continuity of the solution semigroup and the property of exponential asynchronous growth are established for this model.  相似文献   
56.
We study several properties about the problem of domination in the class of positive AM-compact operators, and we obtain some interesting consequences on positive compact operators. Also, we give a sufficient condition under which a Banach lattice is discrete.

  相似文献   

57.
A series of seven new 2′,3′,4′‐substituted spiro[isothiochromene‐3,5′‐isoxazolidin]‐4(1H)‐ones ( 7‐13 ) has been prepared in the reaction of benzylidene(phenyl)azane oxide ( 5 ) or benzylidene(methyl)azane oxide ( 6 ) with (3Z)‐3‐(4‐substituted‐benzylidene)‐1H‐isothio‐ chromen‐4(3H)‐one ( 1‐4 ). The reaction occurs by a 1,3‐dipolar cycloaddition mechanism that leads to the regiospecific formation of various spiroisoxazolidines ( 7‐13 ).  相似文献   
58.
An experimental investigation is performed on a fully developed turbulent channel flow with local injection through a porous strip. The Reynolds number based on the channel half-width was set to 5000. In addition to the no blowing case, measurements are made for three different blowing rates σ = 0.22, 0.36 and 0.58 (where σ is the ratio of momentum flux gain due to the blowing and momentum flux of the incoming channel flow). Measurements carried out with hot-wire anemometry reveal that injection strongly affects both the velocity profiles and the turbulence characteristics. The injection decreases the skin friction coefficient and increases all the Reynolds stresses downstream the blowing strip. The turbulence structure and the bursting phenomena were examined using space-time correlations measurements and conditional analysis. It is found that the injection increases the frequency of occurrence of the bursts.  相似文献   
59.
We study Banach lattices on which each positive semi-compact operator is compact.  相似文献   
60.
We compare the effects of non-standard weak bosons (NSB) expected fromE 6-superstrings (Z′), strong Higgs (V 0) and composite (spin 0, 1, 2) models by using the classical inclusive deep-inelastic “ep” scattering at HERA energies. TheX 2 associated to polarized and unpolarized cross-sections, as well as the six combinations of asymmetries, allow us to derive significant bounds on the masses of the new bosons of various spins associated to some composite models with exception of the excitedZ *. We have also obtained some lower bounds for spin one bosons of different models (Z′,V 0,Z *) which are stronger than the present experimental limits.  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