全文获取类型
收费全文 | 182篇 |
免费 | 14篇 |
国内免费 | 17篇 |
专业分类
化学 | 1篇 |
晶体学 | 1篇 |
力学 | 18篇 |
综合类 | 3篇 |
数学 | 166篇 |
物理学 | 24篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 27篇 |
2012年 | 9篇 |
2011年 | 12篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 24篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有213条查询结果,搜索用时 31 毫秒
161.
Yutaka Hiramine 《Discrete Mathematics》2008,308(15):3257-3264
In this paper we show that if a square transversal design TDλ[k;u], say D(=(P,B)), admits a class semiregular automorphism group G of order s, then we have a by matrix M with entries from G∪{0} satisfying , where , if i=j, and , otherwise. As an application of (*), we show that any symmetric TD2[12;6] admits no nontrivial elation. We also obtain a result that gives us a restriction on the existence of elations of putative projective planes of composite order. 相似文献
162.
Hao Wu 《Transactions of the American Mathematical Society》2008,360(7):3365-3389
We establish some inequalities for the Khovanov-Rozansky cohomologies of braids. These give new upper bounds of the self-linking numbers of transversal links in standard contact which are sharper than the well-known bound given by the HOMFLY polynomial. We also introduce a sequence of transversal link invariants and discuss some of their properties.
163.
We show that a Lipschitz domain can be expanded solely near a part of its boundary, assuming that the part is enclosed by
a piecewise C
1 curve. The expanded domain as well as the extended part are both Lipschitz. We apply this result to prove a regular decomposition
of standard vector Sobolev spaces with vanishing traces only on part of the boundary. Another application in the construction
of low-regularity projectors into finite element spaces with partial boundary conditions is also indicated. 相似文献
164.
1000多年前, 英国著名学者Alcuin曾提出过一个古老的渡河问题, 即狼、羊和卷心菜的渡河问题. 最近, Prisner和Csorba等考虑了一般``冲突图"上的渡河问题. 将这一问题推广到超图$H=(V,\mathcal{E})$\,上, 考虑一类情况更一般的运输计划问题. 现在监管者 欲运输超图中的所有点\,(代表``items")\,渡河, 这里$V$的点子 形成超边 当且仅当这些点代表的``items"在无人监管的情况下不能留在一起. 超图$H$的Alcuin数是指超图$H$具有可行运输方案\,(即把$V$的点代表的``items" 全部运到河对岸)\,时船的最小容量. 给出了 $r$-一致完全二部超图和它的伴随超图, 以及$r$-一致超图的Alcuin数, 同时证明了判断$r$-一致超图是否为小船图是NP 困难的. 相似文献
165.
Yueshan XIONG 《Frontiers of Mathematics in China》2015,10(2):395
The homotopy connectedness theorem for invariant immersions in Sasakian manifolds with nonnegative transversal q-bisectional curvature is proved. Some Barth-Lefschetz type theorems for minimal submanifolds and (k, ?)-saddle submanifolds in Sasakian manifolds with positive transversal q-Ricci curvature are proved by using the weak (?-)asymptotic index. As a corollary, the Frankel type theorem is proved. 相似文献
166.
167.
168.
TiNi相变悬臂梁的横向冲击特性实验研究 总被引:10,自引:0,他引:10
利用改装的霍普金森压杆装置对TiNi形状记忆合金圆截面悬臂梁进行了横向冲击实验研究,并与45#钢悬臂梁的实验结果进行了对比,目的是探索相变对结构动态响应的影响。结果表明:在同样冲击条件下,TiNi悬臂梁的吸能效率优于钢悬臂梁;发现冲击过程中,TiNi试件根部内侧可能形成局部相变铰,使阻力曲线的斜率发生变化;卸载后相变铰消失,TiNi悬臂梁试件基本回复原状,钢试件则留下显著的残余变形。TiNi悬臂梁的冲击特性受热弹性马氏体相变和逆相变的支配,不同于传统的弹塑性机制。 相似文献
169.
Katica 《Acta Mechanica Sinica》2007,23(2):221-229
The double plate system with a discontinuity in the elastic bonding layer of Winker type is studied in this paper. When the
discontinuity is small, it can be taken as an interface crack between the bi-materials or two bodies (plates or beams). By
comparison between the number of multifrequencies of analytical solutions of the double plate system free transversal vibrations
for the case when the system is with and without discontinuity in elastic layer we obtain a theory for experimental vibration
method for identification of the presence of an interface crack in the double plate system. The analytical analysis of free
transversal vibrations of an elastically connected double plate systems with discontinuity in the elastic layer of Winkler
type is presented. The analytical solutions of the coupled partial differential equations for dynamical free and forced vibration
processes are obtained by using method of Bernoulli’s particular integral and Lagrange’s method of variation constants. It
is shown that one mode vibration corresponds an infinite or finite multi-frequency regime for free and forced vibrations induced
by initial conditions and one-frequency or corresponding number of multi-frequency regime depending on external excitations.
It is shown for every shape of vibrations. The analytical solutions show that the discontinuity affects the appearance of
multi-frequency regime of time function corresponding to one eigen amplitude function of one mode, and also that time functions
of different vibration basic modes are coupled. From final expression we can separate the new generalized eigen amplitude
functions with corresponding time eigen functions of one frequency and multi-frequency regime of vibrations.
The English text was polished by Keren Wang. 相似文献
170.
A transversal cover is a set of gk points in k disjoint groups of size g and a minimum collection of transversal subset s, called blocks, such that any pair of points not contained in the same group appear in at least one block. The case g = 2 was investigated and completely solved by Sperner, Renyi, Katona, Kleitman, and Spencer. For all g, asymptotic results are known, but little is understood for small values of k. Sloane and others have initiated the investigation of g = 3. The present article is concerned with constructive techniques for all g and k. One of the principal constructions generalizes Wilson's theorem for transversal designs. This article also discusses a simulated annealing algorithm for finding transversal covers and gives a table of the best known transversal covers at this time. © 1999 John Wiley & Sons, Inc. J Combin Designs 7: 185–203, 1999 相似文献