全文获取类型
收费全文 | 1374篇 |
免费 | 38篇 |
国内免费 | 99篇 |
专业分类
化学 | 7篇 |
晶体学 | 1篇 |
力学 | 23篇 |
综合类 | 16篇 |
数学 | 1251篇 |
物理学 | 213篇 |
出版年
2024年 | 4篇 |
2023年 | 12篇 |
2022年 | 20篇 |
2021年 | 13篇 |
2020年 | 18篇 |
2019年 | 23篇 |
2018年 | 31篇 |
2017年 | 31篇 |
2016年 | 23篇 |
2015年 | 12篇 |
2014年 | 33篇 |
2013年 | 116篇 |
2012年 | 68篇 |
2011年 | 55篇 |
2010年 | 37篇 |
2009年 | 75篇 |
2008年 | 85篇 |
2007年 | 86篇 |
2006年 | 77篇 |
2005年 | 59篇 |
2004年 | 54篇 |
2003年 | 45篇 |
2002年 | 59篇 |
2001年 | 51篇 |
2000年 | 52篇 |
1999年 | 46篇 |
1998年 | 36篇 |
1997年 | 30篇 |
1996年 | 28篇 |
1995年 | 18篇 |
1994年 | 21篇 |
1993年 | 20篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 15篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1978年 | 12篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1974年 | 3篇 |
排序方式: 共有1511条查询结果,搜索用时 15 毫秒
91.
An algorithm is presented for the design of optimal detection filters in radar and communications systems, subject to inequality constraints on the maximum output sidelobe levels. This problem was reduced in an earlier paper (Ref. 1) to an unconstrained one in the dual space of regular Borel measures, with a nondifferentiable cost functional. Here, the dual problem is solved via steepest descent, using the directional Gateaux differential. The algorithm is shown to be convergent, and numerical results are presented.This research was supported by the Australian Research Grants Committee. 相似文献
92.
S. Tanimoto 《Journal of Optimization Theory and Applications》1980,31(3):331-342
For a convex-concave functionL(x, y), we define the functionf(x) which is obtained by maximizingL with respect toy over a specified set. The minimization problem with objective functionf is considered. We derive necessary conditions of optimality for this problem. Based upon these necessary conditions, we define its dual problem. Furthermore, a duality theorem and a converse duality theorem are obtained. It is made clear that these results are extensions of those derived in studies on a class of nondifferentiable mathematical programming problems.This work was supported by the Japan Society for the Promotion of Sciences. 相似文献
93.
94.
We generalize the self-dual parameterization of the SU(2) Yang–Mills field proposed by Niemi and Faddeev for describing the infrared limit of the theory to the case of the gauge group SU(3). We demonstrate that the duality property intrinsic to the SU(2) gauge field cannot be transferred automatically to the higher-rank group case. We interpret the algebraic structures appearing in the Lagrangian for the new compact variables in terms of the group products SU(2)3. 相似文献
95.
Let be a nonempty closed convex subset of a real Banach space and be a Lipschitz pseudocontractive self-map of with . An iterative sequence is constructed for which as . If, in addition, is assumed to be bounded, this conclusion still holds without the requirement that Moreover, if, in addition, has a uniformly Gâteaux differentiable norm and is such that every closed bounded convex subset of has the fixed point property for nonexpansive self-mappings, then the sequence converges strongly to a fixed point of . Our iteration method is of independent interest.
96.
For any subset A of the unit sphere of a Banach space X and for [0,2) the notion of -flatness is introduced as a measure of non-flatness of A. For any positive , construction of locally finite tilings of the unit sphere by -flat sets is carried out under suitable -renormings of X in a quite general context; moreover, a characterization of spaces having separable dual is provided in terms of the existence of such tilings. Finally, relationships between the possibility of getting such tilings of the unit sphere in the given norm and smoothness properties of the norm are discussed. 相似文献
97.
Christopher Allday Bernhard Hanke Volker Puppe 《Proceedings of the American Mathematical Society》2003,131(10):3275-3283
Let , or more generally be a finite -group, where is an odd prime. If acts on a space whose cohomology ring fulfills Poincaré duality (with appropriate coefficients ), we prove a mod congruence between the total Betti number of and a number which depends only on the -module structure of . This improves the well known mod congruences that hold for actions on general spaces.
98.
Regina Sandra Burachik B. F. Svaiter 《Proceedings of the American Mathematical Society》2003,131(8):2379-2383
Recently, the authors studied the connection between each maximal monotone operator and a family of convex functions. Each member of this family characterizes the operator and satisfies two particular inequalities.
The aim of this paper is to establish the converse of the latter fact. Namely, that every convex function satisfying those two particular inequalities is associated to a unique maximal monotone operator.
99.
Jeffrey Hakim 《Journal of Number Theory》2003,100(2):251-269
If G is a totally disconnected group and H is a closed subgroup then, according to the Gelfand-Kazhdan Lemma, if the double coset space H?G/H is preserved by an antiautomorphism of G of order two then (G,H) must be a Gelfand pair in the sense that HomH(π,1) has dimension at most one for each irreducible, admissible representation π of G. Under certain rather general restrictions, we show that if the symmetry property holds only for almost all double cosets, then (G,H) is a supercuspidal Gelfand pair in the sense that for all irreducible, supercuspidal representations π of G. There exist examples of supercuspidal Gelfand pairs which are not Gelfand pairs. 相似文献
100.
S. J. Brodsky 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):638-644
The AdS/CFT correspondence between conformal field theory and string states in an extended space-time has provided new insights
into not only hadron spectra, but also their light-front wave functions. We show that there is an exact correspondence between
the fifth-dimensional coordinate of anti-de Sitter space z and a specific impact variable ζ which measures the separation of the constituents within the hadron in ordinary space-time. This connection allows one to
predict the form of the light-front wave functions of mesons and baryons, the fundamental entities which encode hadron properties
and scattering amplitudes. A new relativistic Schr?dinger light-front equation is found which reproduces the results obtained
using the fifth-dimensional theory. Since they are complete and orthonormal, the AdS/CFT model wave functions can be used
as an initial ansatz for a variational treatment or as a basis for the diagonalization of the light-front QCD Hamiltonian.
A number of applications of light-front wave functions are also discussed. 相似文献