全文获取类型
收费全文 | 8527篇 |
免费 | 381篇 |
国内免费 | 689篇 |
专业分类
化学 | 775篇 |
晶体学 | 7篇 |
力学 | 409篇 |
综合类 | 54篇 |
数学 | 7187篇 |
物理学 | 1165篇 |
出版年
2023年 | 82篇 |
2022年 | 64篇 |
2021年 | 85篇 |
2020年 | 154篇 |
2019年 | 167篇 |
2018年 | 196篇 |
2017年 | 204篇 |
2016年 | 238篇 |
2015年 | 161篇 |
2014年 | 332篇 |
2013年 | 596篇 |
2012年 | 349篇 |
2011年 | 381篇 |
2010年 | 341篇 |
2009年 | 540篇 |
2008年 | 632篇 |
2007年 | 574篇 |
2006年 | 491篇 |
2005年 | 437篇 |
2004年 | 324篇 |
2003年 | 385篇 |
2002年 | 347篇 |
2001年 | 263篇 |
2000年 | 275篇 |
1999年 | 270篇 |
1998年 | 220篇 |
1997年 | 246篇 |
1996年 | 139篇 |
1995年 | 128篇 |
1994年 | 110篇 |
1993年 | 74篇 |
1992年 | 59篇 |
1991年 | 62篇 |
1990年 | 66篇 |
1989年 | 51篇 |
1988年 | 54篇 |
1987年 | 42篇 |
1986年 | 39篇 |
1985年 | 52篇 |
1984年 | 57篇 |
1983年 | 18篇 |
1982年 | 36篇 |
1981年 | 32篇 |
1980年 | 34篇 |
1979年 | 26篇 |
1978年 | 30篇 |
1977年 | 39篇 |
1976年 | 25篇 |
1974年 | 16篇 |
1973年 | 16篇 |
排序方式: 共有9597条查询结果,搜索用时 31 毫秒
31.
Letg:U→ℝ (U open in ℝn) be an analytic and K-subanalytic (i. e. definable in ℝ
an
K
, whereK, the field of exponents, is any subfield ofℝ) function. Then the set of points, denoted Σ, whereg does not admit an analytic extension is K-subanalytic andg can be extended analytically to a neighbourhood of Ū\∑.
Partially supported by the European RTN Network RAAG (contract no. HPRN-CT-00271) 相似文献
32.
Inequalities satisfied by the zeros of the solutions of second-order hypergeometric equations are derived through a systematic use of Liouville transformations together with the application of classical Sturm theorems. This systematic study allows us to improve previously known inequalities and to extend their range of validity as well as to discover inequalities which appear to be new. Among other properties obtained, Szegő's bounds on the zeros of Jacobi polynomials for , are completed with results for the rest of parameter values, Grosjean's inequality (J. Approx. Theory 50 (1987) 84) on the zeros of Legendre polynomials is shown to be valid for Jacobi polynomials with |β|1, bounds on ratios of consecutive zeros of Gauss and confluent hypergeometric functions are derived as well as an inequality involving the geometric mean of zeros of Bessel functions. 相似文献
33.
本文得到了广义区间空间中几个参数型非空交定理,并用此结果证明了一些新型极大极小定理,截口定理,重合定理,以及变分不等式解的存在性定理。本文中的结果包含(1,3,5-12,14-16)中相应结果。 相似文献
34.
Using a method of uniform approximations, necessary and sufficient conditions for a nonsmooth constrained vector-valued minimax problem are established in terms of Mordukhovich subdifferentials. 相似文献
35.
The first aim in the present paper is to give an integral representation for Beppo Levi functions on R
n. Our integral representation is an extension of Sobolev's integral representation given for infinitely differentiable functions with compact support. As applications, continuity and differentiability properties of Beppo Levi functions are studied.Our second aim in this paper is to study the existence of limits at infinity for Beppo Levi functions. We also consider the existence of fine-type limits at infinity with respect to Bessel capacities, which yields the radial limit result at infinity. 相似文献
36.
Regularity of multiwavelets 总被引:7,自引:0,他引:7
The motivation for this paper is an interesting observation made by Plonka concerning the factorization of the matrix symbol associated with the refinement equation for B-splines with equally spaced multiple knots at integers and subsequent developments which relate this factorization to regularity of refinable vector fields over the real line. Our intention is to contribute to this train of ideas which is partially driven by the importance of refinable vector fields in the construction of multiwavelets. The use of subdivision methods will allow us to consider the problem almost entirely in the spatial domain and leads to exact characterizations of differentiability and Hölder regularity in arbitrary L p spaces. We first study the close relationship between vector subdivision schemes and a generalized notion of scalar subdivision schemes based on bi-infinite matrices with certain periodicity properties. For the latter type of subdivision scheme we will derive criteria for convergence and Hölder regularity of the limit function, which mainly depend on the spectral radius of a bi-infinite matrix induced by the subdivision operator, and we will show that differentiability of the limit functions can be characterized by factorization properties of the subdivision operator. By switching back to vector subdivision we will transfer these results to refinable vectors fields and obtain characterizations of regularity by factorization and spectral radius properties of the symbol associated to the refinable vector field. Finally, we point out how multiwavelets can be generated from orthonormal refinable bi-infinite vector fields. 相似文献
37.
Manfred Sommer 《Constructive Approximation》2006,23(2):211-227
Hermite interpolation of 2n + k data by spline spaces of order k with n variable knots counting multiplicities is studied.
A characterization of the minimal spline spaces which admit a solution of the interpolation problem is obtained. A sufficient
condition on uniqueness of interpolating spline functions is given. 相似文献
38.
Nick Peatfield 《Archive for Mathematical Logic》2006,45(6):739-768
Following the introduction and preliminary investigations of analytic Zariski structures in Peatfield and Zilber (Ann pure Appl Logic 132:125–180, 2005) an example of an analytic Zariski structure extending an algebraically closed field is provided. The example is constructed using Hrushovski’s method of free amalgamation, and a topology is introduced in which we can verify the analytic Zariski axioms. 相似文献
39.
We show that the refined analytic torsion is a holomorphic section of the determinant line bundle over the space of complex representations of the fundamental group of a closed oriented odd-dimensional manifold. Further, we calculate the ratio of the refined analytic torsion and the Farber-Turaev combinatorial torsion. As an application, we establish a formula relating the eta-invariant and the phase of the Farber-Turaev torsion, which extends a theorem of Farber and earlier results of ours. This formula allows to study the spectral flow using methods of combinatorial topology. 相似文献
40.
In this paper, we consider questions related to the structure of inverse matrices of linear bounded operators acting in infinite-dimensional complex Banach spaces. We obtain specific estimates of elements of inverse matrices for bounded operators whose matrices have a special structure. Matrices are introduced as special operator-valued functions on an index set. The matrix structure is described by the behavior of the given function on elements of a special partition of the index set. The method used for deriving the estimates is based on an analysis of Fourier series of strongly continuous periodic functions. 相似文献