全文获取类型
收费全文 | 1710篇 |
免费 | 71篇 |
国内免费 | 107篇 |
专业分类
化学 | 37篇 |
晶体学 | 2篇 |
力学 | 45篇 |
综合类 | 30篇 |
数学 | 1627篇 |
物理学 | 147篇 |
出版年
2024年 | 1篇 |
2023年 | 23篇 |
2022年 | 11篇 |
2021年 | 29篇 |
2020年 | 50篇 |
2019年 | 60篇 |
2018年 | 78篇 |
2017年 | 69篇 |
2016年 | 72篇 |
2015年 | 21篇 |
2014年 | 75篇 |
2013年 | 268篇 |
2012年 | 47篇 |
2011年 | 81篇 |
2010年 | 70篇 |
2009年 | 97篇 |
2008年 | 114篇 |
2007年 | 90篇 |
2006年 | 85篇 |
2005年 | 71篇 |
2004年 | 81篇 |
2003年 | 70篇 |
2002年 | 65篇 |
2001年 | 51篇 |
2000年 | 30篇 |
1999年 | 34篇 |
1998年 | 33篇 |
1997年 | 31篇 |
1996年 | 15篇 |
1995年 | 17篇 |
1994年 | 5篇 |
1993年 | 11篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1969年 | 1篇 |
1957年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有1888条查询结果,搜索用时 62 毫秒
71.
Pavel Rehak 《Czechoslovak Mathematical Journal》2001,51(2):303-321
We study oscillatory properties of the second order half-linear difference equation
. It will be shown that the basic facts of oscillation theory for this equation are essentially the same as those for the linear equation
. We present here the Picone type identity, Reid Roundabout Theorem and Sturmian theory for equation (HL). Some oscillation criteria are also given. 相似文献
72.
Let G be a -compact, locally compact group and I be a closed2-sided ideal with finite codimension in L1(G). It is shownthat there are a closed left ideal L having a right boundedapproximate identity and a closed right ideal R having a leftbounded approximate identity such that I = L + R. The proofuses ideas from the theory of boundaries of random walks ongroups. 2000 Mathematics Subject Classification: primary 43A20;secondary 42A85, 43A07, 46H10, 46H40, 60B11. 相似文献
73.
Cecí lia Ferreira Armando Machado 《Proceedings of the American Mathematical Society》2000,128(7):2181-2186
Let denote the set of all -roots of the identity in a Lie group . We show that is always an embedded submanifold of , having the conjugacy classes of its elements as open submanifolds. These conjugacy classes are examples of -symmetric spaces and we show, more generally, that every -symmetric space of a Lie group is a covering manifold of an embedded submanifold of . We compute also the Hessian of the inclusions of and into , relative to the natural connection on the domain and to the symmetric connection on .
74.
Ramanujan's partition congruences can be proved by first showing that the coefficients in the expansions of (q; q)
r
satisfy certain divisibility properties when r = 4, 6 and 10. We show that much more is true. For these and other values of r, the coefficients in the expansions of (q; q)
r
satisfy arithmetic relations, and these arithmetic relations imply the divisibility properties referred to above. We also obtain arithmetic relations for the coefficients in the expansions of (q; q)
r
(q
t; q
t)
s
, for t = 2, 3, 4 and various values of r and s. Our proofs are explicit and elementary, and make use of the Macdonald identities of ranks 1 and 2 (which include the Jacobi triple product, quintuple product and Winquist's identities). The paper concludes with a list of conjectures. 相似文献
75.
76.
A unifying representation for the existing generalized Ball bases and the Bernstein bases are given. Then the dual bases for the Bézier-Said-Wang type generalized bases (BSWGB for short) are presented. The Marsden identity and the mutual transformation formulas between Bézier curve and Bézier-Said-Wang type generalized curve (BSWGB curve) are also given. These results are very useful for the applications of BSWGB curves and their popularization in CAGD. Numerical examples are also given to show the effectiveness of our methods. 相似文献
77.
The dividends-penalty identity is a relation between three functions: the discounted penalty function without dividends, the discounted penalty function if a barrier dividend strategy is applied, and the expected discounted dividends until ruin. The classical model of risk theory is modified in that the deterministic premiums are replaced by a compound Poisson process with exponential jumps. In this model, the dividends-penalty identity is new and can be derived by interpretation. Then the dividends-penalty identity in the classical model is obtained as a limit. 相似文献
78.
79.
Hjalmar Rosengren 《Journal of Combinatorial Theory, Series A》2008,115(3):376-406
We study Schur Q-polynomials evaluated on a geometric progression, or equivalently q-enumeration of marked shifted tableaux, seeking explicit formulas that remain regular at q=1. We obtain several such expressions as multiple basic hypergeometric series, and as determinants and pfaffians of continuous q-ultraspherical or continuous q-Jacobi polynomials. As special cases, we obtain simple closed formulas for staircase-type partitions. 相似文献
80.
Jeffrey Goldstein 《Nonlinear dynamics, psychology, and life sciences》2001,5(3):197-204
This article examines recent attempts to gain insight into philosophical paradoxes through using NDS models employing iterated difference equations and resulting phase portraits and escape time diagrams. The temporal nature of such models is contrasted with an alternative approach based on the a-temporal and non-dynamical construct of a lattice. Finally, there is a discussion of how such strategies for understanding paradox transcend the realm of empirical research and enter territory in the philosophy of mathematics. 相似文献