全文获取类型
收费全文 | 2128篇 |
免费 | 54篇 |
国内免费 | 26篇 |
专业分类
化学 | 1177篇 |
晶体学 | 7篇 |
力学 | 38篇 |
数学 | 442篇 |
物理学 | 544篇 |
出版年
2023年 | 6篇 |
2022年 | 31篇 |
2021年 | 59篇 |
2020年 | 33篇 |
2019年 | 43篇 |
2018年 | 56篇 |
2017年 | 45篇 |
2016年 | 67篇 |
2015年 | 57篇 |
2014年 | 70篇 |
2013年 | 98篇 |
2012年 | 148篇 |
2011年 | 140篇 |
2010年 | 103篇 |
2009年 | 98篇 |
2008年 | 154篇 |
2007年 | 145篇 |
2006年 | 125篇 |
2005年 | 125篇 |
2004年 | 128篇 |
2003年 | 69篇 |
2002年 | 74篇 |
2001年 | 46篇 |
2000年 | 26篇 |
1999年 | 30篇 |
1998年 | 38篇 |
1997年 | 25篇 |
1996年 | 18篇 |
1995年 | 24篇 |
1994年 | 20篇 |
1993年 | 12篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有2208条查询结果,搜索用时 15 毫秒
991.
Large Deviations for Random Trees 总被引:1,自引:0,他引:1
We consider large random trees under Gibbs distributions and prove a Large Deviation Principle (LDP) for the distribution
of degrees of vertices of the tree. The LDP rate function is given explicitly. An immediate consequence is a Law of Large
Numbers for the distribution of vertex degrees in a large random tree. Our motivation for this study comes from the analysis
of RNA secondary structures. 相似文献
992.
Yuri V. Rogovchenko Fatoş Tuncay 《Nonlinear Analysis: Theory, Methods & Applications》2008,69(1):208-221
For a second-order nonlinear differential equation with a damping term, we obtain new oscillation criteria without an assumption that has been required for related results reported in the literature over the last two decades. Two approaches refining the standard integral averaging technique suggested in the paper can be used to derive a variety of simpler oscillation theorems for different classes of nonlinear differential equations, and both sets of oscillation criteria established in the paper are of independent interest. Several examples are provided to illustrate the relevance of the new theorems. 相似文献
993.
994.
Yuri Bakhtin 《Annales Henri Poincare》2012,13(5):1291-1303
We consider a dynamic mean-field ferromagnetic model in the low-temperature regime in the neighborhood of the zero magnetization state. We study the random time it takes for the system to make a decision, i.e., to exit the neighborhood of the unstable equilibrium and approach one of the two stable equilibrium points. We prove a limit theorem for the distribution of this random time in the thermodynamic limit. 相似文献
995.
Ivan S. Maksymov Arthur R. Davoyan Andrey E. Miroshnichenko Constantin Simovski Pavel Belov Yuri S. Kivshar 《Optics Communications》2012,285(5):821-824
We suggest a multifrequency Yagi–Uda-type nanoantenna loaded with an array of tapered plasmonic nanorods. The arrays of director nanorods can be used for the excitation of the nanoantenna by emitters matched spectrally with their resonant frequency and placed in their near-field region. An overlap of multifrequency operating bands of the nanoantenna provides novel opportunities for broadband operation, and the same nanoantenna architecture can be employed both as a transmitter and/or as a receiver, thus being useful for broadband wireless communication. 相似文献
996.
Yuri Bozhkov Igor Leite Freire 《Journal of Mathematical Analysis and Applications》2012,388(2):1279-1284
We carry out a complete group classification of the nonlinear Lane–Emden systems in dimension two. The Noether symmetries are found and their corresponding conservation laws are established. 相似文献
997.
998.
Numerical Algorithms - An algorithm is proposed for finding numerical solutions of a kinetic equation that describes an infinite system of point particles placed in $\mathbb {R}^{d} (d \geq 1)$ .... 相似文献
999.
This paper presents subjective evaluation results for images reproducing metallic luster. The images were produced by a six-band high-dynamic-range imaging technique, which provides high color fidelity and the capability of various tone mapping operations. The preferences for images produced by four kinds of tone mapping operations were evaluated by means of a paired comparison method under the conditions that observers could or could not refer to real scenes. The evaluation results indicated that preferences for images depend on tone mapping operations, especially for objects that have the luster changing over a large area with moderately high intensity. In addition, when referring to a real scene, the spatially varying tone compression, which reproduces the color and complex characteristics of metallic luster, was significantly preferable to the tone mappings by other approaches. Without a real scene, the preference was also strong for images produced by simply saturating pixel values at highlights. 相似文献
1000.
Yuri N. Belokon Victor I. Maleev Dmitri A. Kataev Tatiana F. Saveleva Tatiana V. Skrupskaya Yulia V. Nelyubina Michael North 《Tetrahedron: Asymmetry》2009,20(15):1746-1752
A series of Co(III) anionic complexes of Schiff bases obtained from substituted salicylaldehydes and optically active amino acids has been synthesized. The ion pairing of these anions to a lithium cation can be used to induce asymmetry into lithium-catalyzed trimethylsilylcyanation of aldehydes and Michael reactions. The influence of the temperature, solvent polarity and structural modification of the chiral anion on the enantioselectivity of the catalysis has been investigated. 相似文献