全文获取类型
收费全文 | 152篇 |
免费 | 4篇 |
国内免费 | 12篇 |
专业分类
化学 | 4篇 |
力学 | 2篇 |
数学 | 151篇 |
物理学 | 11篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 12篇 |
2013年 | 26篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 7篇 |
2009年 | 10篇 |
2008年 | 12篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有168条查询结果,搜索用时 15 毫秒
11.
We offer an almost self-contained development of Perron–Frobenius type results for the numerical range of an (irreducible) nonnegative matrix, rederiving and completing the previous work of Issos, Nylen and Tam, and Tam and Yang on this topic. We solve the open problem of characterizing nonnegative matrices whose numerical ranges are regular convex polygons with center at the origin. Some related results are obtained and some open problems are also posed. 相似文献
12.
13.
In this paper, the minimal and maximal nonnegative solutions for second order m-point boundary value problems at resonance are investigated by using a new fixed point theorem of increasing operators. And the monotone iterative sequences which converge to solutions are given. The method is different essentially from the previous papers used by coincidence degree continuation theorem of Mawhin. 相似文献
14.
Due to the extensive applications of nonnegative matrix factorizations (NMFs) of nonnegative matrices, such as in image processing, text mining, spectral data analysis, speech processing, etc., algorithms for NMF have been studied for years. In this paper, we propose a new algorithm for NMF, which is based on an alternating projected gradient (APG) approach. In particular, no zero entries appear in denominators in our algorithm which implies no breakdown occurs, and even if some zero entries appear in numerators new updates can always be improved in our algorithm. It is shown that the effect of our algorithm is better than that of Lee and Seung’s algorithm when we do numerical experiments on two known facial databases and one iris database. 相似文献
15.
G. Landi E. Loli Piccolomini 《Applied mathematics and computation》2011,218(5):2091-2107
In this work, the problem of the restoration of images corrupted by space invariant blur and noise is considered. This problem is ill-posed and regularization is required. The image restoration problem is formulated as a nonnegatively constrained minimization problem whose objective function depends on the statistical properties of the noise corrupting the observed image. The cases of Gaussian and Poisson noise are both considered. A Newton-like projection method with early stopping of the iterates is proposed as an iterative regularization method in order to determine a nonnegative approximation to the original image. A suitable approximation of the Hessian of the objective function is proposed for a fast solution of the Newton system. The results of the numerical experiments show the effectiveness of the method in computing a good solution in few iterations, when compared with some methods recently proposed as best performing. 相似文献
16.
17.
On the Spectra of Striped Sign Patterns 总被引:4,自引:0,他引:4
J. J. McDonald D. D. Olesky M. J. Tsatsomeros P. van den Driessche 《Linear and Multilinear Algebra》2003,51(1):39-48
Sign patterns consisting of some positive and some negative columns, with at least one of each kind, are shown to allow any self-conjugate spectrum, and thus to allow any inertia. In the case of the n ×n sign pattern with all columns positive, given any self-conjugate multiset consisting of n -1 complex numbers supplemented by a sufficiently large positive number, it is shown how to construct a positive normal matrix whose spectrum is this multiset. Thus, the positive sign pattern allows any inertia with at least one positive eigenvalue. 相似文献
18.
Thomas J. Laffey 《Linear algebra and its applications》2006,416(1):148-159
The nonnegative inverse eigenvalue problem (NIEP) is the problem of determining necessary and sufficient conditions for a list of complex numbers σ to be the spectrum of a nonnegative matrix. In this paper the problem is completely solved in the case when all numbers in the given list σ except for one (the Perron eigenvalue) have real parts smaller than or equal to zero. 相似文献
19.
20.
该文讨论了有M P逆的Abel范畴中态射方程αxα*=β的非负定解和正定解.作为其应用,给出了p 除环上矩阵方程AXA*=B的相关结果 相似文献