全文获取类型
收费全文 | 6423篇 |
免费 | 461篇 |
国内免费 | 510篇 |
专业分类
化学 | 558篇 |
晶体学 | 11篇 |
力学 | 400篇 |
综合类 | 75篇 |
数学 | 5229篇 |
物理学 | 1121篇 |
出版年
2023年 | 65篇 |
2022年 | 68篇 |
2021年 | 131篇 |
2020年 | 156篇 |
2019年 | 155篇 |
2018年 | 142篇 |
2017年 | 137篇 |
2016年 | 168篇 |
2015年 | 127篇 |
2014年 | 251篇 |
2013年 | 664篇 |
2012年 | 280篇 |
2011年 | 350篇 |
2010年 | 305篇 |
2009年 | 434篇 |
2008年 | 436篇 |
2007年 | 432篇 |
2006年 | 387篇 |
2005年 | 322篇 |
2004年 | 268篇 |
2003年 | 304篇 |
2002年 | 253篇 |
2001年 | 209篇 |
2000年 | 199篇 |
1999年 | 169篇 |
1998年 | 178篇 |
1997年 | 151篇 |
1996年 | 101篇 |
1995年 | 73篇 |
1994年 | 65篇 |
1993年 | 50篇 |
1992年 | 35篇 |
1991年 | 32篇 |
1990年 | 29篇 |
1989年 | 27篇 |
1988年 | 31篇 |
1987年 | 26篇 |
1986年 | 16篇 |
1985年 | 35篇 |
1984年 | 21篇 |
1983年 | 14篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1974年 | 4篇 |
1973年 | 5篇 |
排序方式: 共有7394条查询结果,搜索用时 31 毫秒
71.
D. H. Armitage 《Journal of Approximation Theory》2002,118(2):225-234
For each compact subset K of
N let
(K) denote the space of functions that are harmonic on some neighbourhood of K. The space
(K) is equipped with the topology of uniform convergence on K. Let Ω be an open subset of
N such that 0Ω and
N\Ω is connected. It is shown that there exists a series ∑Hn, where Hn is a homogeneous harmonic polynomial of degree n on
N, such that (i) ∑Hn converges on some ball of centre 0 to a function that is continuous on Ω and harmonic on Ω, (ii) the partial sums of ∑Hn are dense in
(K) for every compact subset K of
N\Ω with connected complement. Some refinements are given and our results are compared with an analogous theorem concerning overconvergence of power series. 相似文献
72.
Aliasing effects are investigated for spherical random fields sampled on a finite grid. Using the spherical harmonics expansion, it is shown that for a band-limited spherical random field its trend and spectrum can be uniquely reconstructed from the sampled field if the sampling points are judiciously designed. Analytical expressions are also obtained for aliasing errors in the trend and the spectrum when the field is not band-limited. 相似文献
73.
Suppose that the signal X to be estimated is a diffusion process in a random medium W and the signal is correlated with the observation noise. We study the historical filtering problem concerned with estimating the signal path up until the current time based upon the back observations. Using Dirichlet form theory, we introduce a filtering model for general rough signal X
W
and establish a multiple Wiener integrals representation for the unnormalized pathspace filtering process. Then, we construct a precise nonlinear filtering model for the process X itself and give the corresponding Wiener chaos decomposition. 相似文献
74.
青岛港货运吞吐量的时间序列模型 总被引:2,自引:0,他引:2
运用时间序列分析方法对时间序列建立ARMA,ARIMA模型.搜集了青岛港1999年1月~2003年5月的货运吞吐量数据,对进行分析,建立了青岛港货运吞吐量的模型.通过预留的部分数据对模型进行检验,并对模型的残差进行检验,得出模型比较合理. 相似文献
75.
76.
Josef Obermaier 《Journal of Approximation Theory》2003,125(2):303-312
Let
be compact with #S=∞ and let C(S) be the set of all real continuous functions on S. We ask for an algebraic polynomial sequence (Pn)n=0∞ with deg Pn=n such that every fC(S) has a unique representation f=∑i=0∞ αiPi and call such a basis Faber basis. In the special case of
, 0<q<1, we prove the existence of such a basis. A special orthonormal Faber basis is given by the so-called little q-Legendre polynomials. Moreover, these polynomials state an example with A(Sq)≠U(Sq)=C(Sq), where A(Sq) is the so-called Wiener algebra and U(Sq) is the set of all fC(Sq) which are uniquely represented by its Fourier series. 相似文献
77.
用无限阶Toeplitz矩阵求常系数微分方程的级数解 总被引:1,自引:0,他引:1
无限阶Toeplitz矩阵的属于0的特征向量可递推地求得,可表示常系数齐次微分方程的解.用它的逆可求得常系数非齐次微分方程的特解. 相似文献
78.
U. Goginava 《分析论及其应用》2007,23(3):255-265
In this paper we prove that iff ∈ C([-π,π]2) and the function f is bounded partial p-variation for some p ∈ [1, ∞), then the double trigonometric Fourier series of a function f is uniformly (C;-α,-β) summable (α β< 1/p,α,β> 0) in the sense of Pringsheim. If α β≥ 1/p, then there exists a continuous function f0 of bounded partial double trigonometric Fourier series of fo diverge over cubes. 相似文献
79.
A. G. García M. A. Hernndez-Medina 《Journal of Mathematical Analysis and Applications》2003,280(2):221-231
The close relationship between discrete Sturm–Liouville problems belonging to the so-called limit-circle case, the indeterminate Hamburger moment problem and the search of self-adjoint extensions of the associated semi-infinite Jacobi matrix is well known. In this paper, all these important topics are also related with associated sampling expansions involving analytic Lagrange-type interpolation series. 相似文献
80.
Periodica Mathematica Hungarica - 相似文献