全文获取类型
收费全文 | 789篇 |
免费 | 22篇 |
专业分类
化学 | 579篇 |
晶体学 | 10篇 |
力学 | 19篇 |
数学 | 113篇 |
物理学 | 90篇 |
出版年
2023年 | 4篇 |
2022年 | 11篇 |
2021年 | 29篇 |
2020年 | 16篇 |
2019年 | 13篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 29篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 39篇 |
2012年 | 51篇 |
2011年 | 46篇 |
2010年 | 31篇 |
2009年 | 40篇 |
2008年 | 49篇 |
2007年 | 45篇 |
2006年 | 55篇 |
2005年 | 44篇 |
2004年 | 34篇 |
2003年 | 39篇 |
2002年 | 30篇 |
2001年 | 17篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 10篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有811条查询结果,搜索用时 15 毫秒
101.
102.
Giovanna Carnovale 《Acta Appl Math》1998,53(2):187-228
This paper answers a few questions about algebraic aspects of bialgebras, associated with the family of solutions of the quantum Yang–Baxter equation in Acta Appl. Math. 41 (1995), pp. 57–98. We describe the relations of the bialgebras associated with these solutions and the standard deformations of GLn and of the supergroup GL(m|n). We also show how the existence of zero divisors in some of these algebras are related to the combinatorics of their related matrix, providing a necessary and sufficient condition for the bialgebras to be a domain. We consider their Poincaré series, and we provide a Hopf algebra structure to quotients of these bialgebras in an explicit way. We discuss the problems involved with the lift of the Hopf algebra structure, working only by localization. 相似文献
103.
Riassunto Si dimostrano teoremi di esistenza, di unicità e di regolarizzazione per la soluzione del problema di Cauchy-Dirichlet per
una classe di sistemi parabolici a coefficienti misurabili.
Lavoro eseguito nell'ambito del gruppo G.N.A.F.A. del C.N.R. 相似文献
Summary We show that the Cauchy-Dirichlet problem for a class of parabolic systems with measurable coefficients admits a unique solution. We show, also, regularity's properties for the solution.
Lavoro eseguito nell'ambito del gruppo G.N.A.F.A. del C.N.R. 相似文献
104.
We study bilateral problems for a second order parabolic operator with principal part not of divergence form. We prove existence, uniqueness, Holder-continuity and approximation results for both strong and generalized solutions. 相似文献
105.
Giovanna Pizzirani Pierluigi Magagnini Paolo Giusti 《Journal of Polymer Science.Polymer Physics》1971,9(6):1133-1145
The glass transition temperatures of a number of poly(vinyl phenyl ketones), poly-(vinyl benzoates), and poly(phenyl acrylates) have been measured by a refractometric method. The effects exerted on Tg by the nature and position of the ring substituents and by the different groups binding the pendant phenyl rings to the polyvinyl chain are discussed. The importance of knowledge of the side-group motions in the glassy state for the interpretation of glass temperature data is emphasized. 相似文献
106.
107.
Giovanna Carnovale 《Algebras and Representation Theory》2006,9(1):99-120
We show which H
op
-cleft extensions of k for a dual quasi-triangular Hopf algebra (H, r) are H-Azumaya. The result is given in terms of bijectivity of a map defined in terms of the universal r-form r and the 2-cocycle σ, generalizing a well-known result for the commutative and co-commutative case. We illustrate the Theorem with an explicit computation for the Hopf algebras of type E(n).Presented by A. Verschoren 相似文献
108.
Giancarlo Consolo Carmela Currò Giovanna Valenti 《Mathematical Methods in the Applied Sciences》2020,43(18):10474-10489
The formation of Turing vegetation patterns in flat arid environments is investigated in the framework of a generalized version of the hyperbolic Klausmeier model. The extensions here considered involve, on the one hand, the strength of the rate at which rainfall water enters into the soil and, on the other hand, the functional dependence of the inertial times on vegetation biomass and soil water. The study aims at elucidating how the inclusion of these generalized quantities affects the onset of bifurcation of supercritical Turing patterns as well as the transient dynamics observed from an uniformly vegetated state towards a patterned state. To achieve these goals, linear and multiple-scales weakly nonlinear stability analysis are addressed, this latter being inspected in both large and small spatial domains. Analytical results are then corroborated by numerical simulations, which also serve to describe more deeply the spatio-temporal evolution of the emerging patterns as well as to characterize the different timescales involved in vegetation dynamics. 相似文献
109.
In this note we extend the main result in [6] on artinian ideals failing Lefschetz properties, varieties satisfying Laplace equations and existence of suitable singular hypersurfaces. Moreover we characterize the minimal generation of ideals generated by powers of linear forms by the configuration of their dual points in the projective plane and we use this result to improve some propositions on line arrangements and Strong Lefschetz Property at range 2 in [6]. The starting point was an example in [3]. Finally we show the equivalence among failing SLP, Laplace equations and some unexpected curves introduced in [3]. 相似文献
110.
Manlio Gaudioso Giovanni Giallombardo Giovanna Miglionico Adil M. Bagirov 《Journal of Global Optimization》2018,71(1):37-55
We introduce a proximal bundle method for the numerical minimization of a nonsmooth difference-of-convex (DC) function. Exploiting some classic ideas coming from cutting-plane approaches for the convex case, we iteratively build two separate piecewise-affine approximations of the component functions, grouping the corresponding information in two separate bundles. In the bundle of the first component, only information related to points close to the current iterate are maintained, while the second bundle only refers to a global model of the corresponding component function. We combine the two convex piecewise-affine approximations, and generate a DC piecewise-affine model, which can also be seen as the pointwise maximum of several concave piecewise-affine functions. Such a nonconvex model is locally approximated by means of an auxiliary quadratic program, whose solution is used to certify approximate criticality or to generate a descent search-direction, along with a predicted reduction, that is next explored in a line-search setting. To improve the approximation properties at points that are far from the current iterate a supplementary quadratic program is also introduced to generate an alternative more promising search-direction. We discuss the main convergence issues of the line-search based proximal bundle method, and provide computational results on a set of academic benchmark test problems. 相似文献