全文获取类型
收费全文 | 3533篇 |
免费 | 378篇 |
国内免费 | 175篇 |
专业分类
化学 | 2186篇 |
晶体学 | 32篇 |
力学 | 30篇 |
综合类 | 8篇 |
数学 | 907篇 |
物理学 | 923篇 |
出版年
2023年 | 9篇 |
2022年 | 14篇 |
2021年 | 56篇 |
2020年 | 88篇 |
2019年 | 110篇 |
2018年 | 115篇 |
2017年 | 128篇 |
2016年 | 108篇 |
2015年 | 126篇 |
2014年 | 118篇 |
2013年 | 205篇 |
2012年 | 193篇 |
2011年 | 231篇 |
2010年 | 228篇 |
2009年 | 375篇 |
2008年 | 351篇 |
2007年 | 283篇 |
2006年 | 192篇 |
2005年 | 175篇 |
2004年 | 112篇 |
2003年 | 128篇 |
2002年 | 113篇 |
2001年 | 93篇 |
2000年 | 83篇 |
1999年 | 60篇 |
1998年 | 66篇 |
1997年 | 49篇 |
1996年 | 39篇 |
1995年 | 33篇 |
1994年 | 24篇 |
1993年 | 17篇 |
1992年 | 30篇 |
1991年 | 19篇 |
1990年 | 13篇 |
1989年 | 5篇 |
1988年 | 18篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有4086条查询结果,搜索用时 20 毫秒
991.
Gennian Ge 《Discrete Mathematics》2006,306(1):52-65
In this paper, we investigate the existence of resolvable group divisible designs (RGDDs) with block size four, group-type hn and index three. The necessary conditions for the existence of such a design are n?4 and hn≡0. These necessary conditions are shown to be sufficient except for (h,n)∈{(2,4),(2,6)} and possibly excepting (h,n)=(2,54). 相似文献
992.
In this paper, the solution of the nonlinear evolution inclusion problem of the form u′(t)+B(t,u(t))∋f(t) is studied. In this problem, the operators are of type (M) or type (S+), which are different from those of pseudo-monotone operators that had been studied by many authors. At the same time, we study the perturbation problem. In fact, many kinds of evolution equations can be generalized by this problem. The former results are improved and generalized by our conclusions, and we will give more applications. 相似文献
993.
Satoru Fujishige 《Discrete Applied Mathematics》2006,154(6):950-970
In the theory of two-sided matching markets there are two standard models: (i) the marriage model due to Gale and Shapley and (ii) the assignment model due to Shapley and Shubik. Recently, Eriksson and Karlander introduced a hybrid model, which was further generalized by Sotomayor. In this paper, we propose a common generalization of these models by utilizing the framework of discrete convex analysis introduced by Murota, and verify the existence of a pairwise-stable outcome in our general model. 相似文献
994.
We present direct measurements of the lifetime of the 4F5/2 and 2H(2)9/2 manifold in Nd3+:YLiF4, using a fluorescence pump-probe technique. The technique populates the 4F5/2 and 2H(2)9/2 manifold directly with a pump pulse. Via excited state absorption from this excited manifold, the 2F(2)5/2 manifold of Nd3+ is populated with a delayed probe pulse. The population in the 4F5/2 and 2H(2)9/2 manifold is monitored as a function of time by observing the change in integrated UV fluorescence from the 2F(2)5/2 manifold for each time delay between pump and probe pulses. The pump and probe beams come from the fundamental and second harmonic wavelengths of a femtosecond Ti:sapphire regenerative amplifier. The measured lifetime agrees well with the energy gap law, based on other nonradiative lifetime measurements from the literature for Nd3+:YLiF4. 相似文献
995.
Vladimír Špirko 《Journal of Molecular Spectroscopy》2006,235(2):268-270
The potential energy curve of Be2 in its ground electronic state is constructed by morphing accurate MR-CI ab initio potentials from the literature to available experimental ro-vibrational data within the framework of the reduced potential curve (RPC) approach of Jen? and Plíva [Adv. At. Mol. Phys. 19 (1983) 265-307]. The resulting potential energy curves are in close harmony with experiment allowing thus for reliable prediction of the so-far experimentally unprobed part of the molecular potential energy function. 相似文献
996.
Vladimir Nikiforov 《Discrete Mathematics》2010,310(1):125-131
In this note we complete an investigation started by Erd?s in 1963 that aims to find the strongest possible conclusion from the hypothesis of Turán’s theorem in extremal graph theory.Let be the complete r-partite graph with parts of sizes s1≥2,s2,…,sr with an edge added to the first part. Letting tr(n) be the number of edges of the r-partite Turán graph of order n, we prove that:For all r≥2 and all sufficiently small c>0, every graph of sufficiently large order n with tr(n)+1 edges contains a .We also give a corresponding stability theorem and two supporting results of wider scope. 相似文献
997.
Hirobumi Mizuno 《Discrete Mathematics》2010,310(4):782-791
We give a decomposition formula for the determinant on the bond scattering matrix of a regular covering of G. Furthermore, we define an L-function of G, and give a determinant expression of it. As a corollary, we express the determinant on the bond scattering matrix of a regular covering of G by means of its L-functions. 相似文献
998.
Francisco J. Fernández-Polo 《Journal of Functional Analysis》2010,259(2):343-358
We establish several generalisations of Urysohn's lemma in the setting of JB∗-triples which provide full answers to Problems 1.12 and 1.13 in Fernández-Polo and Peralta (2007) [22]. These results extend the previous generalisations obtained by C.A. Akemann, G.K. Pedersen and L.G. Brown in the setting of C∗-algebras. A generalised Kadison's transitivity theorem is established for finite sums of pairwise orthogonal compact tripotents in JBW∗-triples. We introduce the notion of positively open tripotent in the bidual of a JB∗-triple as an extension of a concept which was already considered in the setting of ternary rings of operators. We investigate the connections appearing between positively open tripotents and hereditary inner ideals. 相似文献
999.
Yasuhiko Sato 《Journal of Functional Analysis》2010,259(2):453-476
For projectionless C∗-algebras absorbing the Jiang-Su algebra tensorially, we study a kind of the Rohlin property for automorphisms. We show that the crossed products obtained by automorphisms with this Rohlin property also absorb the Jiang-Su algebra tensorially under a mild technical condition on the C∗-algebras. In particular, for the Jiang-Su algebra we show the uniqueness up to outer conjugacy of the automorphism with this Rohlin property. 相似文献
1000.
Yongqiang Fu 《Journal of Mathematical Analysis and Applications》2010,363(2):679-689
The paper is concerned with the Dirichlet problem of higher order quasilinear elliptic equation: