全文获取类型
收费全文 | 624篇 |
免费 | 38篇 |
国内免费 | 40篇 |
专业分类
化学 | 76篇 |
晶体学 | 4篇 |
力学 | 162篇 |
综合类 | 13篇 |
数学 | 266篇 |
物理学 | 181篇 |
出版年
2023年 | 9篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 21篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 21篇 |
2015年 | 17篇 |
2014年 | 19篇 |
2013年 | 47篇 |
2012年 | 17篇 |
2011年 | 33篇 |
2010年 | 24篇 |
2009年 | 36篇 |
2008年 | 40篇 |
2007年 | 48篇 |
2006年 | 34篇 |
2005年 | 30篇 |
2004年 | 25篇 |
2003年 | 28篇 |
2002年 | 31篇 |
2001年 | 20篇 |
2000年 | 20篇 |
1999年 | 20篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 17篇 |
1992年 | 13篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有702条查询结果,搜索用时 15 毫秒
61.
Gaurav Thakur 《Journal of Functional Analysis》2011,260(8):2283-2299
We study some problems related to the effect of bounded, additive sample noise in the bandlimited interpolation given by the Whittaker-Shannon-Kotelnikov (WSK) sampling formula. We establish a generalized form of the WSK series that allows us to consider the bandlimited interpolation of any bounded sequence at the zeros of a sine-type function. The main result of the paper is that if the samples in this series consist of independent, uniformly distributed random variables, then the resulting bandlimited interpolation almost surely has a bounded global average. In this context, we also explore the related notion of a bandlimited function with bounded mean oscillation. We prove some properties of such functions, and in particular, we show that they are either bounded or have unbounded samples at any positive sampling rate. We also discuss a few concrete examples of functions that demonstrate these properties. 相似文献
62.
A simple and commonly used method to approximate the total claim distribution of a (possibly weakly dependent) insurance collective is the normal approximation. In this article, we investigate the error made when the normal approximation is plugged in a fairly general distribution-invariant risk measure. We focus on the rate of convergence of the error relative to the number of clients, we specify the relative error’s asymptotic distribution, and we illustrate our results by means of a numerical example. Regarding the risk measure, we take into account distortion risk measures as well as distribution-invariant coherent risk measures. 相似文献
63.
64.
Geometry of affine immersions is the study of hypersurfaces that are invariant under affine transformations. As with the hypersurface theory on the Euclidean space, an affine immersion can induce a torsion-free affine connection and a (pseudo)-Riemannian metric on the hypersurface. Moreover, an affine immersion can induce a statistical manifold, which plays a central role in information geometry. Recently, a statistical manifold with a complex structure is actively studied since it connects information geometry and Kähler geometry. However, a holomorphic complex affine immersion cannot induce such a statistical manifold with a Kähler structure. In this paper, we introduce complex affine distributions, which are non-integrable generalizations of complex affine immersions. We then present the fundamental theorem for a complex affine distribution, and show that a complex affine distribution can induce a statistical manifold with a Kähler structure. 相似文献
65.
A mathematical model of superposition of large butt-end and coaxial torsional and axial shear deformations of homogeneous
and fiber-reinforced thick-wall cylinders is constructed. The macroscopic stresses of the reinforced material are additively
determined by matrix stresses and by tensile or constrained compression stresses in the reinforcing fibers. The model is based
on the numerical solution of two boundary-value problems, one of which corresponds to the butt-end torsion and the other to
the coaxial torsion and axial shear. The boundary-value problem on joint deformations is solved with the use of the displacement
field determined from the solution to the boundary-value problem on butt-end torsion. The results obtained by applying this
method to homogeneous and axially-radially reinforced thick-wall cylinders subjected to butt-end torsion with subsequent coaxial
torsion and axial shear are presented.
__________
Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 4, pp. 465–492, July–August, 2007. 相似文献
66.
William M. Baker 《International Journal of Theoretical Physics》2006,45(12):2257-2273
We study theories of gravitation that are based on the Einstein – Hilbert action that are not projectively invariant and can therefore completely determine their connections. We are thus lead to the conclusion that the geometry is necessarily Riemann – Cartan and at least the trace part of a torsion field must be present. We examine the consequence of including these torsion fields in cosmological models. Our results differ from those obtained earlier in the Einstein – Cartan – Sciama – Kibble theory. We also consider a model that includes a series of quadratic torsion terms. This series leads to a potential function that has the effect of “turning on” the cosmological constant. This potential function then acts like dark energy. This model also shows that the torsion field can produce an inflationary period.
PACS: 04.02 Cv, 95.30 Sf, 98.80-k 相似文献
67.
Peter Heering 《Physics in Perspective (PIP)》2006,8(1):52-63
I discuss our replication of the wire-torsion experiments that Charles Augustin Coulomb (1736–1806) reported in a session
of the Paris Académie des Sciences in 1784. I first explain the nature and purpose of the replication method and then apply it to an analysis of Coulomb’s experiments.
I conclude by placing Coulomb’s presentation of his memoir into its specific historical contest. 相似文献
68.
Teik-Cheng Lim 《Journal of mathematical chemistry》2002,31(4):421-428
A set of mathematical relationship between torsion potential functions such as trigonometric and Fourier series is presented herein. A harmonic approximation form is also introduced, and its stiffness constant is related to the parameters of trigonometric and Fourier series. Mathematical relationships between various force field parameters are presented in the form of conversion matrices. 相似文献
69.
Guangxiang Su 《Annals of Global Analysis and Geometry》2007,31(2):181-211
We study the delocalized L
2-analytic torsion introduced by John Lott, and define the delocalized L
2-combinatorial torsion. By using the method of Bismut–Zhang, under the conditions of positive Novikov–Shubin invariants and
finite conjugacy class, we get the Cheeger–Müller type relation between the delocalized L
2-analytic torsion and the delocalized L
2-combinatorial torsion.
相似文献
70.
Fazilet Erkekog˜lu 《Mathematical Physics, Analysis and Geometry》2006,8(4):361-388
The geometry of almost complex manifolds with degenerate indefinite Hermitian metrics is studied. 相似文献