全文获取类型
收费全文 | 4735篇 |
免费 | 449篇 |
国内免费 | 381篇 |
专业分类
化学 | 363篇 |
晶体学 | 16篇 |
力学 | 330篇 |
综合类 | 62篇 |
数学 | 3221篇 |
物理学 | 1573篇 |
出版年
2024年 | 5篇 |
2023年 | 32篇 |
2022年 | 73篇 |
2021年 | 88篇 |
2020年 | 113篇 |
2019年 | 101篇 |
2018年 | 122篇 |
2017年 | 123篇 |
2016年 | 154篇 |
2015年 | 112篇 |
2014年 | 222篇 |
2013年 | 379篇 |
2012年 | 218篇 |
2011年 | 296篇 |
2010年 | 244篇 |
2009年 | 266篇 |
2008年 | 334篇 |
2007年 | 314篇 |
2006年 | 308篇 |
2005年 | 234篇 |
2004年 | 216篇 |
2003年 | 207篇 |
2002年 | 231篇 |
2001年 | 180篇 |
2000年 | 168篇 |
1999年 | 157篇 |
1998年 | 153篇 |
1997年 | 100篇 |
1996年 | 73篇 |
1995年 | 53篇 |
1994年 | 42篇 |
1993年 | 42篇 |
1992年 | 30篇 |
1991年 | 10篇 |
1990年 | 31篇 |
1989年 | 16篇 |
1988年 | 17篇 |
1987年 | 10篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有5565条查询结果,搜索用时 15 毫秒
951.
A. I. Aptekarev J. S. Dehesa A. Martínez-Finkelshtein R. Yáñez 《Constructive Approximation》2009,30(1):93-119
Given a nontrivial Borel measure on ℝ, let p
n
be the corresponding orthonormal polynomial of degree n whose zeros are λ
j
(n), j=1,…,n. Then for each j=1,…,n,
with
defines a discrete probability distribution. The Shannon entropy of the sequence {p
n
} is consequently defined as
In the case of Chebyshev polynomials of the first and second kinds, an explicit and closed formula for
is obtained, revealing interesting connections with number theory. In addition, several results of numerical computations
exemplifying the behavior of
for other families are presented.
相似文献
952.
BOUNDARY BEHAVIOR OF CAUCHY-TYPE INTEGRALS IN CLIFFORD ANALYSIS 总被引:1,自引:0,他引:1
In this article,the authors discussed the boundary behavior for the Cauchy- type integrals with values in a Clifford algebra,obtained some Sochocki–Plemelj formulae and Privalov–Muskhelishvili theorems for the Cauchy-type integral taken over a smooth surface by rather simple method. 相似文献
953.
Nan GAO 《数学年刊B辑(英文版)》2009,30(3):231-238
The relative transpose via Gorenstein projective modules is introduced, and some corresponding results on the Auslander-Reiten sequences and the Auslander-Reiten formula to this relative version are generalized. 相似文献
954.
Z.K. Eshkuvatov N.M.A. Nik Long M. Abdulkawi 《Journal of Computational and Applied Mathematics》2009,233(2):334-345
New quadrature formulas (QFs) for evaluating the singular integral (SI) of Cauchy type with unbounded weight function on the edges is constructed. The construction of the QFs is based on the modification of discrete vortices method (MMDV) and linear spline interpolation over the finite interval [−1,1]. It is proved that the constructed QFs converge for any singular point x not coinciding with the end points of the interval [−1,1]. Numerical results are given to validate the accuracy of the QFs. The error bounds are found to be of order O(hα|lnh|) and O(h|lnh|) in the classes of functions Hα([−1,1]) and C1([−1,1]), respectively. 相似文献
955.
An efficient algorithm is described for calculating stationary one-dimensional transonic outflow solutions of the compressible Euler equations with gravity and heat source terms. The stationary equations are solved directly by exploiting their dynamical system form. Transonic expansions are the stable manifolds of saddle-point-type critical points, and can be obtained efficiently and accurately by adaptive integration outward from the critical points. The particular transonic solution and critical point that match the inflow boundary conditions are obtained by a two-by-two Newton iteration which allows the critical point to vary within the manifold of possible critical points. The proposed Newton Critical Point (NCP) method typically converges in a small number of Newton steps, and the adaptively calculated solution trajectories are highly accurate. A sample application area for this method is the calculation of transonic hydrodynamic escape flows from extrasolar planets and the early Earth. The method is also illustrated for an example flow problem that models accretion onto a black hole with a shock. 相似文献
956.
General local convergence theorems with order of convergence r≥1 are provided for iterative processes of the type xn+1=Txn, where T:D⊂X→X is an iteration function in a metric space X. The new local convergence theory is applied to Newton iteration for simple zeros of nonlinear operators in Banach spaces as well as to Schröder iteration for multiple zeros of polynomials and analytic functions. The theory is also applied to establish a general theorem for the uniqueness ball of nonlinear equations in Banach spaces. The new results extend and improve some results of [K. Do?ev, Über Newtonsche Iterationen, C. R. Acad. Bulg. Sci. 36 (1962) 695–701; J.F. Traub, H. Wo?niakowski, Convergence and complexity of Newton iteration for operator equations, J. Assoc. Comput. Mach. 26 (1979) 250–258; S. Smale, Newton’s method estimates from data at one point, in: R.E. Ewing, K.E. Gross, C.F. Martin (Eds.), The Merging of Disciplines: New Direction in Pure, Applied, and Computational Mathematics, Springer, New York, 1986, pp. 185–196; P. Tilli, Convergence conditions of some methods for the simultaneous computation of polynomial zeros, Calcolo 35 (1998) 3–15; X.H. Wang, Convergence of Newton’s method and uniqueness of the solution of equations in Banach space, IMA J. Numer. Anal. 20 (2000) 123–134; I.K. Argyros, J.M. Gutiérrez, A unified approach for enlarging the radius of convergence for Newton’s method and applications, Nonlinear Funct. Anal. Appl. 10 (2005) 555–563; M. Giusti, G. Lecerf, B. Salvy, J.-C. Yakoubsohn, Location and approximation of clusters of zeros of analytic functions, Found. Comput. Math. 5 (3) (2005) 257–311], and others. 相似文献
957.
958.
Yoon Tae Kim 《Journal of Mathematical Analysis and Applications》2009,359(1):106-125
We introduce two types of the Stratonovich stochastic integrals for two-parameter processes, and investigate the relationship of these Stratonovich integrals and various types of Skorohod integrals with respect to a fractional Brownian sheet. By using this relationship, we derive a differentiation formula in the Stratonovich sense for fractional Brownian sheet through Itô formula. Also the relationship between the two types of the Stratonovich integrals will be obtained and used to derive a differentiation formula in the Stratonovich sense. In this case, our proof is based on the repeated applications of differentiation formulas in the Stratonovich form for one-parameter Gaussian processes. 相似文献
959.
For parallel neighborhoods of the paths of the d ‐dimensional Brownian motion, so‐called Wiener sausages, formulae for the expected surface area are given for any dimension d ≥ 2. It is shown by means of geometric arguments that the expected surface area is equal to the first derivative of the mean volume of the Wiener sausage with respect to its radius (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
960.
Carles Bivià-Ausina 《Mathematische Zeitschrift》2009,262(2):389-409
Let be a finite analytic map. We give an expression for the local Łojasiewicz exponent and for the multiplicity of g when the component functions of g satisfy certain condition with respect to a set of n monomial ideals I
1,..., I
n
. We give an effective method to compute Łojasiewicz exponents based on the computation of mixed multiplicities. As a consequence
of our study, we give a numerical characterization of a class of functions that includes semi-weighted homogenous functions
and Newton non-degenerate functions.
Work supported by DGICYT Grant MTM2006-06027. 相似文献