全文获取类型
收费全文 | 1890篇 |
免费 | 51篇 |
国内免费 | 6篇 |
专业分类
化学 | 1362篇 |
晶体学 | 14篇 |
力学 | 12篇 |
数学 | 273篇 |
物理学 | 286篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 32篇 |
2021年 | 41篇 |
2020年 | 37篇 |
2019年 | 48篇 |
2018年 | 37篇 |
2017年 | 25篇 |
2016年 | 66篇 |
2015年 | 63篇 |
2014年 | 63篇 |
2013年 | 137篇 |
2012年 | 129篇 |
2011年 | 152篇 |
2010年 | 103篇 |
2009年 | 107篇 |
2008年 | 139篇 |
2007年 | 117篇 |
2006年 | 109篇 |
2005年 | 99篇 |
2004年 | 87篇 |
2003年 | 56篇 |
2002年 | 57篇 |
2001年 | 23篇 |
2000年 | 19篇 |
1999年 | 22篇 |
1998年 | 13篇 |
1997年 | 16篇 |
1996年 | 18篇 |
1995年 | 13篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 2篇 |
1980年 | 8篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
排序方式: 共有1947条查询结果,搜索用时 15 毫秒
101.
Marcos T.O. Pimenta Sérgio H.M. Soares 《Journal of Mathematical Analysis and Applications》2012,390(1):274-289
Some superlinear fourth order elliptic equations are considered. A family of solutions is proved to exist and to concentrate at a point in the limit. The proof relies on variational methods and makes use of a weak version of the Ambrosetti–Rabinowitz condition. The existence and concentration of solutions are related to a suitable truncated equation. 相似文献
102.
Miguel Andrés Marcos 《Potential Analysis》2016,45(2):201-227
In this paper we introduce Bessel potentials and the Sobolev potential spaces resulting from them in the context of Ahlfors regular metric spaces. The Bessel kernel is defined using a Coifman type approximation of the identity, and we show integration against it improves the regularity of Lipschitz, Besov and Sobolev-type functions. For potential spaces, we prove density of Lipschitz functions, and several embedding results, including Sobolev-type embedding theorems. Finally, using singular integrals techniques such as the T1 theorem, we find that for small orders of regularity Bessel potentials are inversible, its inverse in terms of the fractional derivative, and show a way to characterize potential spaces, concluding that a function belongs to the Sobolev potential space if and only if itself and its fractional derivative are in Lp. Moreover, this characterization allows us to prove these spaces in fact coincide with the classical potential Sobolev spaces in the Euclidean case. 相似文献
103.
Given an Ext-injective stratifying system of Λ-modules satisfying that the projective dimension of Y is finite, we prove that the finitistic dimension of the algebra Λ is equal to the finitistic dimension of the category . Moreover, using the theory of stratifying systems we obtain bounds for the finitistic dimension of Λ. In particular, we get the optimal bound 2n-2 for the finitistic dimension of a standardly stratified algebra with n simples. 相似文献
104.
Lana Mara Rodrigues dos Santos Philippe Michelon Marcos Nereu Arenales Ricardo Henrique Silva Santos 《Annals of Operations Research》2011,190(1):165-180
In this article we propose a 0-1 optimization model to determine a crop rotation schedule for each plot in a cropping area. The rotations have the same duration in all the plots and the crops are selected to maximize plot occupation. The crops may have different production times and planting dates. The problem includes planting constraints for adjacent plots and also for sequences of crops in the rotations. Moreover, cultivating crops for green manuring and fallow periods are scheduled into each plot. As the model has, in general, a great number of constraints and variables, we propose a heuristics based on column generation. To evaluate the performance of the model and the method, computational experiments using real-world data were performed. The solutions obtained indicate that the method generates good results. 相似文献
105.
We investigate the existence and properties of solutions for a class of systems of Dirichlet problems involving the perturbed phi-Laplace operators. We apply variational methods associated with the Fenchel conjugate. Our results cover both sublinear and superlinear cases of nonlinearities. 相似文献
106.
Julio Becerra Guerrero Fernando Rambla-Barreno 《Journal of Mathematical Analysis and Applications》2009,360(1):254-264
We prove that for every member X in the class of real or complex JB*-triples or preduals of JBW*-triples, the following assertions are equivalent:
- (1) X has the fixed point property.
- (2) X has the super fixed point property.
- (3) X has normal structure.
- (4) X has uniform normal structure.
- (5) The Banach space of X is reflexive.
Keywords: JB*-triple; Fixed point; Normal structure 相似文献
107.
Julio Becerra Guerrero ngel Rodríguez Palacios 《Journal of Mathematical Analysis and Applications》2009,360(1):108-118
Almost transitive superreflexive Banach spaces have been considered in [C. Finet, Uniform convexity properties of norms on superreflexive Banach spaces, Israel J. Math. 53 (1986) 81–92], where it is shown that they are uniformly convex and uniformly smooth. We characterize such spaces as those convex transitive Banach spaces satisfying conditions much weaker than that of uniform convexity (for example, that of having a weakly locally uniformly rotund point). We note that, in general, the property of convex transitivity for a Banach space is weaker than that of almost transitivity. 相似文献
108.
We consider surfaces with parallel mean curvature vector field and finite total curvature in product spaces of type \({\mathbb {M}}^n(c)\times {\mathbb {R}}\), where \({\mathbb {M}}^n(c)\) is a space form and characterize certain of these surfaces. When \(n=2\), our results are similar to those obtained in Bérard et al. (Ann Glob Anal Geom 16(3):273–290, 1998) for surfaces with constant mean curvature in space forms. 相似文献
109.
110.