全文获取类型
收费全文 | 357篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
化学 | 5篇 |
力学 | 1篇 |
数学 | 330篇 |
物理学 | 26篇 |
出版年
2023年 | 22篇 |
2022年 | 21篇 |
2021年 | 15篇 |
2020年 | 20篇 |
2019年 | 13篇 |
2018年 | 13篇 |
2017年 | 19篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 20篇 |
2013年 | 43篇 |
2012年 | 8篇 |
2011年 | 23篇 |
2010年 | 13篇 |
2009年 | 23篇 |
2008年 | 16篇 |
2007年 | 22篇 |
2006年 | 14篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有362条查询结果,搜索用时 15 毫秒
1.
3.
Canonical correlation analysis based on information theory 总被引:2,自引:0,他引:2
In this article, we propose a new canonical correlation method based on information theory. This method examines potential nonlinear relationships between p×1 vector Y-set and q×1 vector X-set. It finds canonical coefficient vectors a and b by maximizing a more general measure, the mutual information, between aTX and bTY. We use a permutation test to determine the pairs of the new canonical correlation variates, which requires no specific distributions for X and Y as long as one can estimate the densities of aTX and bTY nonparametrically. Examples illustrating the new method are presented. 相似文献
4.
PSN is a fast forward permutation if for each m the computational complexity of evaluating Pm(x) is small independently of m and x. Naor and Reingold constructed fast forward pseudorandom cycluses and involutions. By studying the evolution of permutation graphs, we prove that the number of queries needed to distinguish a random cyclus from a random permutation in SN is Θ(N) if one does not use queries of the form Pm(x), but is only Θ(1) if one is allowed to make such queries. We construct fast forward permutations which are indistinguishable from random permutations even when queries of the form Pm(x) are allowed. This is done by introducing an efficient method to sample the cycle structure of a random permutation, which in turn solves an open problem of Naor and Reingold. 相似文献
5.
A statistic is found to combinatorially generate the cycle-counting q-hit numbers, defined algebraically by Haglund [Adv. in Appl. Math. 17 (1996) 408–459]. We then define the notion of a cycle-Mahonian pair of statistics (generalizing that of a Mahonian statistic), and show that our newly discovered statistic is part of such a pair. Finally, we note a second example of a cycle-Mahonian pair of statistics which leads us to define the stronger property of being a cycle-Euler–Mahonian pair. 相似文献
6.
《Journal of computational and graphical statistics》2013,22(4):946-953
When designing programs or software for the implementation of Monte Carlo (MC) hypothesis tests, we can save computation time by using sequential stopping boundaries. Such boundaries imply stopping resampling after relatively few replications if the early replications indicate a very large or a very small p value. We study a truncated sequential probability ratio test (SPRT) boundary and provide a tractable algorithm to implement it. We review two properties desired of any MC p value, the validity of the p value and a small resampling risk, where resampling risk is the probability that the accept/reject decision will be different than the decision from complete enumeration. We show how the algorithm can be used to calculate a valid p value and confidence intervals for any truncated SPRT boundary. We show that a class of SPRT boundaries is minimax with respect to resampling risk and recommend a truncated version of boundaries in that class by comparing their resampling risk (RR) to the RR of fixed boundaries with the same maximum resample size. We study the lack of validity of some simple estimators of p values and offer a new, simple valid p value for the recommended truncated SPRT boundary. We explore the use of these methods in a practical example and provide the MChtest R package to perform the methods. 相似文献
7.
We consider four classes of polynomials over the fields , , , , , , , where . We find sufficient conditions on the pairs for which these polynomials permute and we give lower bounds on the number of such pairs. 相似文献
8.
Magdy H. Metry Allan R. Sampson 《Journal of computational and graphical statistics》2013,22(2):209-223
Abstract This article introduces an approach for characterizing the classes of empirical distributions that satisfy certain positive dependence notions. Mathematically, this can be expressed as studying certain subsets of the class SN of permutations of 1, …, N, where each subset corresponds to some positive dependence notions. Explicit techniques for it-eratively characterizing subsets of SN that satisfy certain positive dependence concepts are obtained and various counting formulas are given. Based on these techniques, graph-theoretic methods are used to introduce new and more efficient algorithms for constructively generating and enumerating the elements of various of these subsets of SN. For example, the class of positively quadrant dependent permutations in SN is characterized in this fashion. 相似文献
9.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(6):1884-1897
This paper proposes a novel color image cryptosystem based on synchronization of two different six-dimensional hyperchaotic systems. In the transmitter end, we apply the drive system to generate the diffusion matrices and scrambling ones, which are used to change the image pixel value and position, respectively. Thus the ciphered image is obtained. In the receiver, synchronization of two nonidentical hyperchaotic systems can be achieved by designing the appropriate controllers. The response system is employed to yield the corresponding diffusion matrices and scrambling ones using the same generation method in the encryption algorithm. Then the cipher-image can be decrypted by the decryption algorithm, which is similar to that of the encryption process but in the reversed order. The experimental results show that the presented image cryptosystem has high security and can resist noise and crop attacks. 相似文献