全文获取类型
收费全文 | 406篇 |
免费 | 30篇 |
国内免费 | 32篇 |
专业分类
化学 | 49篇 |
力学 | 13篇 |
综合类 | 9篇 |
数学 | 360篇 |
物理学 | 37篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 18篇 |
2015年 | 8篇 |
2014年 | 24篇 |
2013年 | 32篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 31篇 |
2007年 | 27篇 |
2006年 | 19篇 |
2005年 | 21篇 |
2004年 | 19篇 |
2003年 | 21篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 19篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
排序方式: 共有468条查询结果,搜索用时 250 毫秒
71.
Samala
Rathan 《国际流体数值方法杂志》2020,92(12):1927-1947
This article presents an improved fifth-order finite difference weighted essentially nonoscillatory (WENO) scheme to solve Hamilton-Jacobi equations. A new type of nonlinear weights is introduced with the construction of local smoothness indicators on each local stencil that are measured with the help of generalized undivided differences in L1-norm. A novel global smoothness measurement is also constructed with the help of local measurements from its linear combination. Numerical experiments are conducted in one- and two-dimensions to demonstrate the performance enhancement, resolution power, numerical accuracy for the proposed scheme, and compared it with the classical WENO scheme. 相似文献
72.
73.
A new third‐order WENO scheme is proposed to achieve the desired order of convergence at the critical points for scalar hyperbolic equations. A new reference smoothness indicator is introduced, which satisfies the sufficient condition on the weights for the third‐order convergence. Following the truncation error analysis, we have shown that the proposed scheme achieves the desired order accurate for smooth solutions with arbitrary number of vanishing derivatives if the parameter ε satisfies certain conditions. We have made a comparative study of the proposed scheme with the existing schemes such as WENO‐JS, WENO‐Z, and WENO‐N3 through different numerical examples. The result shows that the proposed scheme (WENO‐MN3) achieves better performance than these schemes. 相似文献
74.
Shiying Zhao 《Proceedings of the American Mathematical Society》1997,125(7):2013-2020
The relation between approach regions and singularities of nonnegative kernels is studied, where , , , and is a homogeneous space. For , a sufficient condition on approach regions () is given so that the maximal function
is weak-type with respect to a pair of measures and . It is shown that this condition is also necessary for operators of potential type in the sense of Sawyer and Wheedon (Amer. J. Math. 114 (1992), 813-874).
75.
H. Aimar L. Forzani F. J. Martí n-Reyes 《Proceedings of the American Mathematical Society》1997,125(7):2057-2064
In this note we consider singular integrals associated to Calderón-Zygmund kernels. We prove that if the kernel is supported in then the one-sided condition, , is a sufficient condition for the singular integral to be bounded in , , or from into weak- if . This one-sided condition becomes also necessary when we require the uniform boundedness of the singular integrals associated to the dilations of a kernel which is not identically zero in . The two-sided version of this result is also obtained: Muckenhoupts condition is necessary for the uniform boundedness of the singular integrals associated to the dilations of a general Calderón-Zygmund kernel which is not the function zero either in or in .
76.
M. Felten 《Acta Mathematica Hungarica》2008,118(3):265-297
The paper is concerned with bounds for integrals of the type
, involving Jacobi polynomials p
n
(α,β)
and Jacobi weights w
(a,b)
depending on α,β, a, b > −1, where the subsets U
k
(x) ⊂ [−1, 1] located around x and are given by with . The functions to be integrated will also be of the type on the domain [−1,1] t/ U
k
(x). This approach uses estimates of Jacobi polynomials modified Jacobi weights initiated by Totik and Lubinsky in [1]. Various
bounds for integrals involving Jacobi weights will be derived. The results of the present paper form the basis of the proof
of the uniform boundedness of (C, 1) means of Jacobi expansions in weighted sup norms in [3].
相似文献
77.
It is known that a projective linear two-weight code C over a finite field corresponds both to a set of points in a projective space over that meets every hyperplane in either a or b points for some integers a < b, and to a strongly regular graph whose vertices may be identified with the codewords of C. Here we extend this classical result to the case of a ring-linear code with exactly two nonzero homogeneous weights and
sets of points in an associated projective ring geometry. We will introduce regular projective two-weight codes over finite
Frobenius rings, we will show that such a code gives rise to a strongly regular graph, and we will give some constructions
of two-weight codes using ring geometries. All these examples yield infinite families of strongly regular graphs with non-trivial
parameters.
相似文献
78.
Daniel Girela José Ángel Peláez Fernando Pérez-González Jouni Rättyä 《Integral Equations and Operator Theory》2008,61(4):511-547
In this paper we study the positive Borel measures μ on the unit disc in for which the Bloch space is continuously included in , 0 < p < ∞. We call such measures p-Bloch-Carleson measures. We give two conditions on a measure μ in terms of certain logarithmic integrals one of which is a necessary condition and the other a sufficient condition for μ being a p-Bloch-Carleson measure. We also give a complete characterization of the p-Bloch-Carleson measures within certain special classes of measures. It is also shown that, for p > 1, the p-Bloch-Carleson measures are exactly those for which the Toeplitz operator , defined by , maps continuously into the Bergman space A
1, . Furthermore, we prove that if p > 1, α >-1 and ω is a weight which satisfies the Bekollé-Bonami -condition, then the measure defined by is a p-Bloch-Carleson-measure.
We also consider the Banach space of those functions f which are analytic in and satisfy , as . The Bloch space is contained in . We describe the p-Carleson measures for and study weighted composition operators and a class of integration operators acting in this space. We determine which of
these operators map continuously to the weighted Bergman space and show that they are automatically compact.
This research is partially supported by several grants from “the Ministerio de Educación y Ciencia, Spain” (MTM2005-07347,
MTM2007-60854, MTM2006-26627-E, MTM2007-30904-E and Ingenio Mathematica (i-MATH) No. CSD2006-00032); from “La Junta de Andalucía”
(FQM210 and P06-FQM01504); from “the Academy of Finland” (210245) and from the European Networking Programme “HCAA” of the
European Science Foundation. 相似文献
79.
80.
Michael Schlosser 《Journal of Combinatorial Theory, Series A》2007,114(3):505-521
We enumerate lattice paths in the planar integer lattice consisting of positively directed unit vertical and horizontal steps with respect to a specific elliptic weight function. The elliptic generating function of paths from a given starting point to a given end point evaluates to an elliptic generalization of the binomial coefficient. Convolution gives an identity equivalent to Frenkel and Turaev's summation. This appears to be the first combinatorial proof of the latter, and at the same time of some important degenerate cases including Jackson's and Dougall's summation. By considering nonintersecting lattice paths we are led to a multivariate extension of the summation which turns out to be a special case of an identity originally conjectured by Warnaar, later proved by Rosengren. We conclude with discussing some future perspectives. 相似文献