全文获取类型
收费全文 | 564篇 |
免费 | 49篇 |
国内免费 | 68篇 |
专业分类
化学 | 85篇 |
晶体学 | 2篇 |
力学 | 42篇 |
综合类 | 16篇 |
数学 | 431篇 |
物理学 | 105篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 18篇 |
2019年 | 11篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 19篇 |
2013年 | 52篇 |
2012年 | 24篇 |
2011年 | 36篇 |
2010年 | 19篇 |
2009年 | 30篇 |
2008年 | 41篇 |
2007年 | 36篇 |
2006年 | 46篇 |
2005年 | 35篇 |
2004年 | 25篇 |
2003年 | 27篇 |
2002年 | 29篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 23篇 |
1998年 | 18篇 |
1997年 | 19篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1936年 | 1篇 |
排序方式: 共有681条查询结果,搜索用时 15 毫秒
91.
首先证明了正三角形的外接椭圆中面积最小的是一个圆.进而用初等方法证明了二维情形的F.John定理. 相似文献
92.
93.
陈计 《宁波大学学报(理工版)》1993,(1)
Erds和Klamkin在1973年建立了如下命题:若A,B,C是一个三角形的内角,λ≥2且0≤μ≤λ,则存在以cos~μ(A/λ),cos~μ(B/λ),cos~μ(C/λ)为边的三角形。本文把μ的范围延拓成0≤μ≤λ~2/2后,证明原结论照样成立。 相似文献
94.
Let f and g be elements of the isometry group Isom(H2) of the hyperbolic plane H2, and assume that one of them is orientation-reversing. We determine when the group (f,g) they generate is discrete; in particular, we obtain the classification of such groups. As an application to knot theory, we completely determine the tunnel number one Montesinos knots. 相似文献
95.
We prove the following extended version of Simons' inequality and present its applications. Let be a set and be a subset of . Let be a subset of a Hausdorff topological vector space which is invariant under infinite convex combinations. Let be a bounded function such that the functions are convex for all and whenever 0$">, and Let be a sequence in . Assume that, for every , there exists satisfying . Then
If , then the set in the above inequality can be replaced by .
If , then the set in the above inequality can be replaced by .
96.
V. I. Parusnikov 《Mathematical Notes》2005,77(3-4):523-538
Davenport and Swinnerton-Dyer found the first 19 extremal ternary cubic forms g
i, which have the same meaning as the well-known Markov forms in the binary quadratic case. Bryuno and Parusnikov recently computed the Klein polyhedra for the forms g
1 – g
4. They also computed the convergents for various matrix generalizations of the continued fractions algorithm for multiple root vectors and studied their position with respect to the Klein polyhedra. In the present paper, we compute the Klein polyhedra for the forms g
5, – g
7 and the adjoint form g
7
*
. Their periods and fundamental domains are found and the expansions of the multiple root vectors of these forms by means of the matrix algorithms due to Euler, Jacobi, Poincaré, Brun, Parusnikov, and Bryuno, are computed. The position of the convergents of the continued fractions with respect to the Klein polyhedron is used as a measure of quality of the algorithms. Eulers and Poincarés algorithms proved to be the worst ones from this point of view, and the Bryuno one is the best. However, none of the algorithms generalizes all the properties of continued fractions.Translated from Matematicheskie Zametki, vol. 77, no. 4, 2005, pp. 566–583.Original Russian Text Copyright © 2005 by V. I. Parusnikov.This revised version was published online in April 2005 with a corrected issue number. 相似文献
97.
Defining nonlocality in a no-input closed quantum network scenario is a new area of interest nowadays. Gisin, in [Entropy 21, 325 (2019)], proposed a possible condition for non-tri-locality of the trivial no-input closed network scenario, triangle network, by introducing a new kind of joint measurement bases and a probability bound. In [npj Quantum Information (2020) 6:70] they found a shred of numerical evidence in support of Gisin's probability bound. Now based on that probability bound, it finds the nature of the correlation in a triangle network scenario. This study observes how far the probability lies from that Gisin's bound with every possible combination of entangled and local pure states distributed from three independent quantum sources. Here, it uses the generalized Elegant Joint Measurements bases for each party and find that there is a dependency of non-locality on the entanglement of these joint measurement bases. It also checks the probability bound for the polygon structure. 相似文献
98.
Ewan Davies Rmi de Joannis de Verclos Ross J. Kang Franois Pirot 《Random Structures and Algorithms》2020,57(3):730-744
We prove two distinct and natural refinements of a recent breakthrough result of Molloy (and a follow‐up work of Bernshteyn) on the (list) chromatic number of triangle‐free graphs. In both our results, we permit the amount of color made available to vertices of lower degree to be accordingly lower. One result concerns list coloring and correspondence coloring, while the other concerns fractional coloring. Our proof of the second illustrates the use of the hard‐core model to prove a Johansson‐type result, which may be of independent interest. 相似文献
99.
On Schwarzian Triangle Functions,Automorphic Forms and a Generalization of Ramanujan’s Triple Differential Equations 下载免费PDF全文
Li Chien Shen 《数学学报(英文版)》2018,34(11):1648-1662
Let G be the group of the fractional linear transformations generated by where m, n is a pair of integers with either n ≥ 2,m ≥ 3 or n ≥ 3,m ≥ 2; τ lies in the upper half plane H.
A fundamental set of functions f0, fi and f∞ automorphic with respect to G will be constructed from the conformal mapping of the fundamental domain of G. We derive an analogue of Ramanujan’s triple differential equations associated with the group G and establish the connection of f0, fi and f∞ with a family of hypergeometric functions. 相似文献
$$T(\tau ) = \tau + \lambda ,S(\tau ) = \frac{{\tau \cos \frac{\pi }{n} + \sin \frac{\pi }{n}}}{{ - \tau \sin \frac{\pi }{n} + \cos \frac{\pi }{n}}};$$
$$\lambda = 2\frac{{\cos \frac{\pi }{m} + \cos \frac{\pi }{n}}}{{\sin \frac{\pi }{n}}};$$
100.
In the present work, we first modify the Sprott's nonlinear love triangle model by introducing the competition term and find that the new system also exhibits chaotic behavior. Then, to make the model more realistic, we go further to construct its corresponding fractional-order system and get the necessary condition for the existence of chaotic attractors. Finally, based on an improved version of Adams Bashforth Moulton numerical algorithm, we validate the chaotic attractors of this new fractional-order love triangle system by computer simulations. 相似文献