全文获取类型
收费全文 | 2840篇 |
免费 | 169篇 |
国内免费 | 335篇 |
专业分类
化学 | 492篇 |
晶体学 | 16篇 |
力学 | 65篇 |
综合类 | 24篇 |
数学 | 2138篇 |
物理学 | 609篇 |
出版年
2024年 | 7篇 |
2023年 | 36篇 |
2022年 | 42篇 |
2021年 | 50篇 |
2020年 | 43篇 |
2019年 | 83篇 |
2018年 | 75篇 |
2017年 | 73篇 |
2016年 | 55篇 |
2015年 | 51篇 |
2014年 | 110篇 |
2013年 | 265篇 |
2012年 | 85篇 |
2011年 | 134篇 |
2010年 | 132篇 |
2009年 | 201篇 |
2008年 | 221篇 |
2007年 | 202篇 |
2006年 | 200篇 |
2005年 | 167篇 |
2004年 | 106篇 |
2003年 | 134篇 |
2002年 | 140篇 |
2001年 | 81篇 |
2000年 | 78篇 |
1999年 | 80篇 |
1998年 | 75篇 |
1997年 | 44篇 |
1996年 | 54篇 |
1995年 | 44篇 |
1994年 | 39篇 |
1993年 | 29篇 |
1992年 | 29篇 |
1991年 | 26篇 |
1990年 | 6篇 |
1989年 | 13篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1974年 | 8篇 |
1973年 | 4篇 |
排序方式: 共有3344条查询结果,搜索用时 15 毫秒
101.
Sergio A. Celani 《Central European Journal of Mathematics》2003,1(4):561-572
In this paper we shall give a topological representation for Hilbert algebras that extend the topological representation given
by A. Diego in [4]. For implicative semilattices this representation gives a full duality. We shall also consider the representation
for Boolean ring. 相似文献
102.
In several complex variables, the multivariate Padé-type approximation theory is based on the polynomial interpolation of the multidimensional Cauchy kernel and leads to complicated computations. In this paper, we replace the multidimensional Cauchy kernel by the Bergman kernel function K
(z,x) into an open bounded subset of C
n
and, by using interpolating generalized polynomials for K
(z,x), we define generalized Padé-type approximants to any f in the space OL
2() of all analytic functions on which are of class L
2. The characteristic property of such an approximant is that its Fourier series representation with respect to an orthonormal basis for OL
2() matches the Fourier series expansion of f as far as possible. After studying the error formula and the convergence problem, we show that the generalized Padé-type approximants have integral representations which give rise to the consideration of an integral operator – the so-called generalized Padé-type operator – which maps every f
OL
2() to a generalized Padé-type approximant to f. By the continuity of this operator, we obtain some convergence results about series of analytic functions of class L
2. Our study concludes with the extension of these ideas into every functional Hilbert space H and also with the definition and properties of the generalized Padé-type approximants to a linear operator of H into itself. As an application we prove a Painlevé-type theorem in C
n
and we give two examples making use of generalized Padé-type approximants. 相似文献
103.
J. Arvesú L. L. Littlejohn F. Marcellán 《Journal of Computational Analysis and Applications》2002,4(4):363-387
In this paper, we further develop the left-definite and right-definite spectral theory associated with the self-adjoint differential operator A in L2(-1,1), generated from the classical second-order Legendre differential equation, having the sequence of Legendre polynomials as eigenfunctions. Specifically, we determine the first three left-definite spaces associated with the pair (L2(-1,1),A). As a consequence of these results, we determine the explicit domain of both the associated left-definite operator A1, first observed by Everitt, and the self-adjoint operator A1/2. In addition, we give a new characterization of the domain D(A) of A and, as a corollary, we present a new proof of the Everitt-Mari result which gives optimal global smoothness of functions in D(A). 相似文献
104.
We solve a boundary interpolation problem in the reproducing kernel Hilbert space of functions analytic in the unit ball of
with reproducing kernel 1/(1−∑1Nzkwk*). We introduce the notion of Brune factor (or Blaschke–Potapov factor of the third kind) in this setting. 相似文献
105.
106.
Zoran IVKOVIC 《数学年刊B辑(英文版)》2000,21(1):109-114
ThispaperisanoutcomeofnumerousdiscusionsandexchangeofideaswithlatePredragPerunicic,whosedeepandprofoundmathematicalknowledgeandhumanvaluesgaveusaninspirationandmotivationtofinalizeourjointideas.1.Wereferto[3,4]forthenotionofspectralmultiplicitytheoryintheseparableHilbertspace.LetHbeacyclicHilbertspacewiththeresolutionoftheidentity{p(t)}ofthemaximalspectraltypelIP(dt)ll'~dt-ordinaryLebesguemeasure.Anon-anticipativelineartransformationsisdefinedbyVolterrakernelg(t,u),uSt,ajsf'g(t)u)p(du),t>0… 相似文献
107.
关于hilbert-ingham不等式和它的应用 总被引:4,自引:1,他引:4
本文给出(i)hilbert不等式和hilbert-ingham不等式一些有意义的共同改进;(ii)一些fejer-riesz型不等式的改进和(iii)hardy不等式的改进. 相似文献
108.
A. Nowakowski 《Journal of Optimization Theory and Applications》1986,50(1):129-147
In this paper, on the basis of Young's method (Ref. 1), sufficient conditions for a strong relative minimum in an optimal control problem are given. Young's method generalizes geodesic coverings and the simplest Hilbert integral from the standard variational calculus. This paper carries Young's method over to nonparametric problems. 相似文献
109.
F. M. Mukhamedov 《Mathematical Notes》2000,67(1):81-86
In this paper an analog of the Blum-Hanson theorem for quantum quadratic processes on the von Neumann algebra is proved, i.e.,
it is established that the following conditions are equivalent:
Translated fromMatematicheskie Zametki, Vol. 67, No. 1, pp. 102–109, January, 2000. 相似文献
i) | P( t )x is weakly convergent tox 0; |
ii) | for any sequence {a n} of nonnegative integrable functions on [1, ∞) such that ∝ 1 ∞ a n(t)dt=1 for anyn and lim n→∞ ∥a n∥∞=0, the integral ∝ 1 ∞ a n(t)P( t )x dt is strongly convergent tox 0 inL 2(M, ϕ), wherex ɛM,P( t ) is a quantum quadratic process,M is a von Neumann algebra, andϕ is an exact normal state onM. |
110.
B.P. Duggal 《Journal of Mathematical Analysis and Applications》2005,312(2):502-513
A Hilbert space operator T∈B(H) is hereditarily normaloid (notation: T∈HN) if every part of T is normaloid. An operator T∈HN is totally hereditarily normaloid (notation: T∈THN) if every invertible part of T is normaloid. We prove that THN-operators with Bishop's property (β), also THN-contractions with a compact defect operator such that and non-zero isolated eigenvalues of T are normal, are not supercyclic. Take A and B in THN and let dAB denote either of the elementary operators in B(B(H)): ΔAB and δAB, where ΔAB(X)=AXB−X and δAB(X)=AX−XB. We prove that if non-zero isolated eigenvalues of A and B are normal and , then dAB is an isoloid operator such that the quasi-nilpotent part H0(dAB−λ) of dAB−λ equals −1(dAB−λ)(0) for every complex number λ which is isolated in σ(dAB). If, additionally, dAB has the single-valued extension property at all points not in the Weyl spectrum of dAB, then dAB, and the conjugate operator , satisfy Weyl's theorem. 相似文献