全文获取类型
收费全文 | 130篇 |
免费 | 2篇 |
国内免费 | 23篇 |
专业分类
力学 | 1篇 |
数学 | 128篇 |
物理学 | 26篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 2篇 |
2011年 | 7篇 |
2010年 | 9篇 |
2009年 | 14篇 |
2008年 | 9篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有155条查询结果,搜索用时 250 毫秒
71.
This is a collection of open problems which touch on Neil Hindman's mathematics and were collected in conjunction with the Conference on Ramsey Theory and Topological Algebra in his honor. 相似文献
72.
73.
For a Tychonoff space X , we denote by Cp(X) and Cc(X) the space of continuous real-valued functions on X equipped with the topology of pointwise convergence and the compact-open topology respectively. Providing a characterization of the Lindelöf Σ-property of X in terms of Cp(X), we extend Okunev?s results by showing that if there exists a surjection from Cp(X) onto Cp(Y) (resp. from Lp(X) onto Lp(Y)) that takes bounded sequences to bounded sequences, then υY is a Lindelöf Σ-space (respectively K-analytic) if υX has this property. In the second part, applying Christensen?s theorem, we extend Pelant?s result by proving that if X is a separable completely metrizable space and Y is first countable, and there is a quotient linear map from Cc(X) onto Cc(Y), then Y is a separable completely metrizable space. We study also a non-separable case, and consider a different approach to the result of J. Baars, J. de Groot, J. Pelant and V. Valov, which is based on the combination of two facts: Complete metrizability is preserved by ?p-equivalence in the class of metric spaces (J. Baars, J. de Groot, J. Pelant). If X is completely metrizable and ?p-equivalent to a first-countable Y, then Y is metrizable (V. Valov). Some additional results are presented. 相似文献
74.
Jan J. Dijkstra 《Proceedings of the American Mathematical Society》2008,136(12):4461-4466
We prove that every separable and metrizable space admits a metrizable compactification with a remainder that is both path connected and locally path connected. This result answers a question of P. Simon.
75.
Scott A. Starks Olga Kosheleva Vladik Kreinovich 《International Journal of Theoretical Physics》2006,45(3):576-588
After the 1916 success of general relativity that explained gravity by adding time as a fourth dimension, physicists have been trying to explain other physical fields by adding extra dimensions. In 1921, Kaluza and Klein has shown that under certain conditions like cylindricity (∂ g
ij
/∂ x
5 = 0), the addition of the 5th dimension can explain the electromagnetic field. The problem with this approach is that while the model itself is geometric, conditions like cylindricity are not geometric. This problem was partly solved by Einstein and Bergman who proposed, in their 1938 paper, that the 5th dimension is compactified into a small circle S
1 so that in the resulting cylindric 5D space-time R
4× S
1 the dependence on x
5 is not macroscopically noticeable. We show that if, in all definitions of vectors, tensors, etc., we replace R
4 with R
4× S
1, then conditions like cylindricity automatically follow – i.e., these conditions become fully geometric.
PACS: 11.10.Kk Field theories in dimensions other than four, 04.50.+h Gravity in more than four dimensions. 相似文献
76.
We define the gamma-compactification of an arbitrary measurable space and study its structure and properties in the general and topological cases. We introduce and study the notion of gamma-extension of a singleton in a topological space. We consider the procedure of extension of finitely additive measures from the original space to regular countably additive measures on the gamma-compactification of the space. 相似文献
77.
Mahmoud Filali 《Journal of Functional Analysis》2007,250(1):144-166
The paper proposes a unified approach to many key theorems proved in the last twenty years in different areas of abstract harmonic analysis. This approach is based on the so-called slowly oscillating functions which were introduced in coarse geometry. In addition to this method being the most natural and simple, it also leads to the generalisation of some of the results and to the achievement of some new results. Several of these results concern the topological centres of convolution algebras and semigroup compactifications. 相似文献
78.
S. V. Shadrin 《Functional Analysis and Its Applications》2002,36(2):162-163
For any connected component H
0 of the space of real meromorphic functions we construct a compactification N(H
0). Then we express the Euler characteristics of the spaces H
0 and N(H
0) in terms of topological invariants of functions in H
0. 相似文献
79.
We investigate the structure of singular Calabi–Yau varieties in moduli spaces that contain a Brieskorn–Pham point. Our main tool is a construction of families of deformed motives over the parameter space. We analyze these motives for general fibers and explicitly compute the L-series for singular fibers for several families. We find that the resulting motivic L-functions agree with the L-series of modular forms whose weight depends both on the rank of the motive and the degree of the degeneration of the variety. Surprisingly, these motivic L-functions are identical in several cases to L-series derived from weighted Fermat hypersurfaces. This shows that singular Calabi–Yau spaces of non-conifold type can admit a string worldsheet interpretation, much like rational theories, and that the corresponding irrational conformal field theories inherit information from the Gepner conformal field theory of the weighted Fermat fiber of the family. These results suggest that phase transitions via non-conifold configurations are physically plausible. In the case of severe degenerations we find a dimensional transmutation of the motives. This suggests further that singular configurations with non-conifold singularities may facilitate transitions between Calabi–Yau varieties of different dimensions. 相似文献
80.
An endomorphism on an algebra 𝒜 is said to be “strong” if it is compatible with every congruence on 𝒜; and 𝒜 is said to have the “strong endomorphism kernel property” if every congruence on 𝒜, different from the universal congruence, is the kernel of a strong endomorphism on 𝒜. Here we consider this property in the context of Ockham algebras. In particular, for those MS-algebras that have this property we describe the structure of their dual space in terms of 1-point compactifications of discrete spaces. 相似文献