全文获取类型
收费全文 | 173篇 |
免费 | 5篇 |
国内免费 | 12篇 |
专业分类
化学 | 4篇 |
力学 | 9篇 |
数学 | 140篇 |
物理学 | 37篇 |
出版年
2022年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 22篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 12篇 |
2009年 | 21篇 |
2008年 | 11篇 |
2007年 | 17篇 |
2006年 | 15篇 |
2005年 | 15篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1989年 | 1篇 |
排序方式: 共有190条查询结果,搜索用时 31 毫秒
1.
This paper presents a technique that allows the direct linearidentification of frequency response functions from the computation ofa weighted integral transform. This transform allows toemphasize the influence of the poles and zeros of the frequencyresponse functions its formation is based on the Cauchy--Weierstrass theorem. It isthen shown that this transform is directly linked to a complex wavelettransform. This representation with a wavelet transform provides abetter understanding of the amplification effects of the weightedintegral transform and allows the singularities analysis. 相似文献
2.
《Analytical letters》2012,45(6):1167-1186
ABSTRACT A signal processing technique based on orthogonal wavelet analysis is applied to process various simulated electroanalytical signals. The results indicate that if the scale parameters are selected, the orthogonal wavelet processing method (OWPM) can remove high-frequency noise. Experimental signal was recorded by computer and used to test the OWPM procedure. After processing with OWPM, the processed data was used to analyze the mechanism of the electrode reactions. Processed results of the experimental data are also satisfactory. 相似文献
3.
Cartoon-like images, i.e., C2 functions which are smooth apart from a C2 discontinuity curve, have by now become a standard model for measuring sparse (nonlinear) approximation properties of directional representation systems. It was already shown that curvelets, contourlets, as well as shearlets do exhibit sparse approximations within this model, which are optimal up to a log-factor. However, all those results are only applicable to band-limited generators, whereas, in particular, spatially compactly supported generators are of uttermost importance for applications.In this paper, we present the first complete proof of optimally sparse approximations of cartoon-like images by using a particular class of directional representation systems, which indeed consists of compactly supported elements. This class will be chosen as a subset of (non-tight) shearlet frames with shearlet generators having compact support and satisfying some weak directional vanishing moment conditions. 相似文献
4.
Solving diffusion equation using wavelet method 总被引:1,自引:0,他引:1
Xuefeng ChenJiawei Xiang 《Applied mathematics and computation》2011,217(13):6426-6432
A wavelet-based numerical method based on wavelets of Hermite cubic splines is presented for computing singularly perturbed convection-dominated diffusion equation. The advantages of the method are explained. To improve the accuracy of singular areas, wavelets are configured hierarchically for solving algebraic equations. Numerical examples show that the proposed method has good efficiency and precision. 相似文献
5.
Commodity futures have long been used to facilitate risk management and inventory stabilization. The study of commodity futures prices has attracted much attention in the literature because they are highly volatile and because commodities represent a large proportion of the export value in many developing countries. Previous research has found apparently contradictory findings about the presence of long memory or more generally, long-range dependence. This note investigates the nature of long-range dependence in the volatility of 14 energy and agricultural commodity futures price series using the improved Hurst coefficient (H) estimator of Abry, Teyssière and Veitch. This estimator is motivated by the ability of wavelets to detect self-similarity and also enables a test for the stability of H. The results show evidence of long-range dependence for all 14 commodities and of a non-stationary H for 9 of 14 commodities. 相似文献
6.
A new wavelet multigrid method 总被引:1,自引:0,他引:1
The standard multigrid procedure performs poorly or may break down when used to solve certain problems, such as elliptic problems with discontinuous or highly oscillatory coefficients. The method discussed in this paper solves this problem by using a wavelet transform and Schur complements to obtain the necessary coarse grid, interpolation, and restriction operators. A factorized sparse approximate inverse is used to improve the efficiency of the resulting method. Numerical examples are presented to demonstrate the versatility of the method. 相似文献
7.
Solving Multi-dimensional Evolution Problems with Localized Structures using Second Generation Wavelets 总被引:2,自引:0,他引:2
Oleg V. Vasilyev 《International Journal of Computational Fluid Dynamics》2013,27(2):151-168
A dynamically adaptive numerical method for solving multi-dimensional evolution problems with localized structures is developed. The method is based on the general class of multi-dimensional second-generation wavelets and is an extension of the second-generation wavelet collocation method of Vasilyev and Bowman to two and higher dimensions and irregular sampling intervals. Wavelet decomposition is used for grid adaptation and interpolation, while O ( N ) hierarchical finite difference scheme, which takes advantage of wavelet multilevel decomposition, is used for derivative calculations. The prowess and computational efficiency of the method are demonstrated for the solution of a number of two-dimensional test problems. 相似文献
8.
The stock market is a complex self-interacting system, characterized by intermittent behaviour. Periods of high activity alternate with periods of relative calm. In the present work we investigate empirically the possibility that the market is in a self-organized critical state (SOC). A wavelet transform method is used in order to separate high activity periods, related to the avalanches found in sandpile models, from quiescent. A statistical analysis of the filtered data shows a power law behaviour in the avalanche size, duration and laminar times. The memory process, implied by the power law distribution of the laminar times, is not consistent with classical conservative models for self-organized criticality. We argue that a “near-SOC” state or a time dependence in the driver, which may be chaotic, can explain this behaviour. 相似文献
9.
Anestis Antoniadis Andrey Feuerverger Paulo Gonçalves 《Annals of the Institute of Statistical Mathematics》2006,58(4):779-807
Stable distributions are characterized by four parameters which can be estimated via a number of methods, and although approximate
maximum likelihood estimation techniques have been proposed, they are computationally intensive and difficult to implement.
This article describes a fast, wavelet-based, regression-type method for estimating the parameters of a stable distribution.
Fourier domain representations, combined with a wavelet multiresolution approach, are shown to be effective and highly efficient
tools for inference in stable law families. Our procedures are illustrated and compared with other estimation methods using
simulated data, and an application to a real data example is explored. One novel aspect of this work is that here wavelets
are being used to solve a parametric problem, rather than a nonparametric one, which is the more typical context in wavelet
applications. 相似文献
10.
本文在离散多尺度分析框架了讨论了关于给定数据的分解和回复过程的数值特征.它给出了数据分解和回复算法的一般设计原则,它能有效地解释在正交小波基和双正交小波基下的数据分解回复过程.据此设计原则,文中还给出了一种新的数据分解回复方法,它可以在线性分层基背景下得到解释. 相似文献