全文获取类型
收费全文 | 1376篇 |
免费 | 88篇 |
国内免费 | 196篇 |
专业分类
化学 | 47篇 |
晶体学 | 6篇 |
力学 | 66篇 |
综合类 | 32篇 |
数学 | 1265篇 |
物理学 | 244篇 |
出版年
2024年 | 6篇 |
2023年 | 20篇 |
2022年 | 20篇 |
2021年 | 31篇 |
2020年 | 39篇 |
2019年 | 49篇 |
2018年 | 53篇 |
2017年 | 70篇 |
2016年 | 17篇 |
2015年 | 24篇 |
2014年 | 44篇 |
2013年 | 351篇 |
2012年 | 29篇 |
2011年 | 63篇 |
2010年 | 30篇 |
2009年 | 60篇 |
2008年 | 72篇 |
2007年 | 84篇 |
2006年 | 57篇 |
2005年 | 55篇 |
2004年 | 60篇 |
2003年 | 62篇 |
2002年 | 50篇 |
2001年 | 52篇 |
2000年 | 47篇 |
1999年 | 42篇 |
1998年 | 47篇 |
1997年 | 28篇 |
1996年 | 21篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1660条查询结果,搜索用时 520 毫秒
101.
扭曲的方法在构造新的代数结构与余代数结构中起了重要的作用.本文首先把扭曲的方法运用到模与余模的构造中,得到扭曲模和扭曲余模;其次在更加一般的情形下给出相关扭曲Hopf模的基本同构定理;最后考虑在HopfYD模中如何使扭曲模构成相关Yetter-Drinfel'd模和相关Hopf模. 相似文献
102.
本文利用Finsler约度量函数与度量张量获得了二维Finsler空间是共形平坦的若干令新的充要条件.此外,还推导了在共形映射下,局部Minkowski空间、常曲率Finsler空间与零曲率Finsler空间保持不变的新的充要条件. 相似文献
103.
本文研究局部对称共形平坦黎曼流形中紧致极小子流形,得到了这类子流形第二基本形式模长平方关于外围空间Ricci曲率的—个拼挤定理,推广了文[1]中的结果. 相似文献
104.
Let M be a concircularly flat totally real minimal submanifold in CP~4. The infimum V_m of the volume V(M) of M is obtained, also the necessary and sufficient conditions of "V(M)=V_m" is given. 相似文献
105.
Jean-Christophe Aval 《Discrete Mathematics》2002,256(3):557-575
The aim of this work is to study some lattice diagram determinants ΔL(X,Y) as defined in (Adv. Math. 142 (1999) 244) and to extend results of Aval et al. (J. Combin. Theory Ser. A, to appear). We recall that ML denotes the space of all partial derivatives of ΔL. In this paper, we want to study the space Mi,jk(X,Y) which is defined as the sum of ML spaces where the lattice diagrams L are obtained by removing k cells from a given partition, these cells being in the “shadow” of a given cell (i,j) in a fixed Ferrers diagram. We obtain an upper bound for the dimension of the resulting space Mi,jk(X,Y), that we conjecture to be optimal. This dimension is a multiple of n! and thus we obtain a generalization of the n! conjecture. Moreover, these upper bounds associated to nice properties of some special symmetric differential operators (the “shift” operators) allow us to construct explicit bases in the case of one set of variables, i.e. for the subspace Mi,jk(X) consisting of elements of 0 Y-degree. 相似文献
106.
We have investigated two conformally flat tilted Bianchi Type-V cosmological models in general relativity. To get a determinate
solution, we have assumed a supplementary conditionA =B
n between metric potentials wheren is a constant. The behaviour of the model forn = 2 is discussed in detail. Various physical and geometrical aspects of the models are also discussed. 相似文献
107.
O. I. Mokhov 《Theoretical and Mathematical Physics》2002,133(2):1557-1564
We prove that two Dubrovin–Novikov Hamiltonian operators are compatible if and only if one of these operators is the Lie derivative of the other operator along a certain vector field. We consider the class of flat manifolds, which correspond to arbitrary pairs of compatible Dubrovin–Novikov Hamiltonian operators. Locally, these manifolds are defined by solutions of a system of nonlinear equations, which is integrable by the method of the inverse scattering problem. We construct the integrable hierarchies generated by arbitrary pairs of compatible Dubrovin–Novikov Hamiltonian operators. 相似文献
108.
关于随机共轭空间的各种定义及随机线性泛函各种有界性的某些评论 总被引:2,自引:0,他引:2
中心目的是详细廉政论在随机共轭空间理论形成过程中所经历的三个阶段的工作,尤其指出了这三个阶段工作之间的联系及本质差别;给出了强有界、拓扑有界及几乎处处有界随机线性泛函之间的关系;亦指出了在概率赋范空间上线性算子理论研究中目前存在的不足. 相似文献
109.
O. I. Mokhov 《Theoretical and Mathematical Physics》2007,152(2):1183-1190
We prove that the associativity equations of two-dimensional topological quantum field theories are very natural reductions
of the fundamental nonlinear equations of the theory of submanifolds in pseudo-Euclidean spaces and give a natural class of
flat torsionless potential submanifolds. We show that all flat torsionless potential submanifolds in pseudo-Euclidean spaces bear natural structures
of Frobenius algebras on their tangent spaces. These Frobenius structures are generated by the corresponding flat first fundamental
form and the set of the second fundamental forms of the submanifolds (in fact, the structural constants are given by the set
of the Weingarten operators of the submanifolds). We prove that each N-dimensional Frobenius manifold can be locally represented
as a flat torsionless potential submanifold in a 2N-dimensional pseudo-Euclidean space. By our construction, this submanifold
is uniquely determined up to motions. Moreover, we consider a nonlinear system that is a natural generalization of the associativity
equations, namely, the system describing all flat torsionless submanifolds in pseudo-Euclidean spaces, and prove that this
system is integrable by the inverse scattering method.
To the memory of my wonderful mother Maya Nikolayevna Mokhova (4 May 1926–12 September 2006)
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 152, No. 2, pp. 368–376, August, 2007. 相似文献
110.
Jiu-Kang Yu 《Compositio Mathematica》2003,138(2):189-197
We formulate and prove a Sato–Tate equidistribution law for Drinfeld modules. 相似文献