全文获取类型
收费全文 | 267717篇 |
免费 | 2051篇 |
国内免费 | 623篇 |
专业分类
化学 | 141984篇 |
晶体学 | 4162篇 |
力学 | 11922篇 |
综合类 | 9篇 |
数学 | 29481篇 |
物理学 | 82833篇 |
出版年
2019年 | 2289篇 |
2018年 | 3114篇 |
2017年 | 3110篇 |
2016年 | 4482篇 |
2015年 | 2656篇 |
2014年 | 4279篇 |
2013年 | 10671篇 |
2012年 | 8067篇 |
2011年 | 9892篇 |
2010年 | 7081篇 |
2009年 | 6874篇 |
2008年 | 9308篇 |
2007年 | 9509篇 |
2006年 | 8878篇 |
2005年 | 8069篇 |
2004年 | 7420篇 |
2003年 | 6732篇 |
2002年 | 6657篇 |
2001年 | 7325篇 |
2000年 | 5659篇 |
1999年 | 4359篇 |
1998年 | 3859篇 |
1997年 | 3844篇 |
1996年 | 3583篇 |
1995年 | 3332篇 |
1994年 | 3491篇 |
1993年 | 3189篇 |
1992年 | 3663篇 |
1991年 | 3666篇 |
1990年 | 3599篇 |
1989年 | 3457篇 |
1988年 | 3568篇 |
1987年 | 3463篇 |
1986年 | 3285篇 |
1985年 | 4360篇 |
1984年 | 4631篇 |
1983年 | 3872篇 |
1982年 | 4005篇 |
1981年 | 3931篇 |
1980年 | 3908篇 |
1979年 | 3876篇 |
1978年 | 4190篇 |
1977年 | 4107篇 |
1976年 | 4173篇 |
1975年 | 3849篇 |
1974年 | 3894篇 |
1973年 | 4050篇 |
1972年 | 2851篇 |
1971年 | 2378篇 |
1970年 | 2177篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Steven G. Buyske 《Geometriae Dedicata》1992,44(1):7-16
In 1980 Chern and Terng defined a Bäcklund transformation for affine minimal surfaces. In this paper we show that this Bäcklund transformation can be simply represented by an involution and translation of the affine conormal. 相似文献
92.
93.
G. O. Balabanyan 《Theoretical and Mathematical Physics》1991,89(1):1106-1119
Moscow Institute of Electronic Engineering. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 89, No. 1, pp. 132–150, October, 1991. 相似文献
94.
A new microscopic model of anomalous muonium for the elemental semiconductors is proposed. The relevant configuration consisting
of both a diamagrentic molecule Si−Mu and an unpaired orbital e− is contained into a semivacancy of the real lattice. By using the unrestricted Hartree-Fock computational method the principal
properties of the system are established. A dynamical version of the model together with a question on the formation of such
system are discussed. 相似文献
95.
A random-medium model which is a correlated distribution of points (particles) randomly positioned in the 3-dimensional space
is considered. The construction of the medium starts from a noncorrelated (Poisson) distribution of parent particles, each
of them initiates a finite Markov chain of its descendants. The complete collection of correlation functions of all orders
within the scope of the model have been obtained. The use of the 3-dimensional stable law (Lévy law) as a transition probability
allows us to present the correlation function in an explicit form.
Proceedings of the XVII Seminar on Stability Problems for Stochastic Models, Kazan, Russian, 1995, Part II. 相似文献
96.
97.
V. G. Lomadze 《Acta Appl Math》1994,34(3):305-312
Kalman's theory is extended to a complete, smooth, and irreducible algebraic curve of arbitrary genus. 相似文献
98.
A method is proposed for evaluating the resistance of a flywheel rim to radial stresses in free rotation. The method is based on loading a rim segment in pure bending and calculating the limiting moment and the corresponding limiting angular velocity. Applicability of the method is substantiated theoretically by investigating the similarity of the radial stress diagrams in rotation and pure bending. The method is verified experimentally for the strained state of a rim segment in pure bending.Translated from Mekhanika Kompozitnykh Materialov, Vol. 29, No. 4, pp. 521–526, July–August, 1993. 相似文献
99.
A. G. Meshkov 《Physics letters. A》1992,170(6):405-408
The equation for the Noether operator is obtained. It gives the necessary conditions for complete integrability of the field equations. For several double-component models the Hamiltonian pairs and the recursion operators are presented. 相似文献
100.
Poly (n-butylisocyanate)-benzene solutions prepared by solubilization at 45°C, followed by aging at room temperature were found to be metastable for months, although, eventually, they separated into a birefringent polymer-rich phase and an isotropic solution. These metastable solutions, as well as isothermally phase-separated biphasic samples, flowed and exhibited dynamic moduli indicative of low polymer connectivity. By contrast samples prepared by a freeze-thaw cycle were uniformly and highly birefringent and showed network (gel) behavior at room temperature. The mechanism of gel formation is most likely the exclusion of the polymer from the benzene crystal during crystallization, forcing the polymer to align and exist at grain boundaries. Films formed from solutions have different moduli than those formed from gels, and are consistent with the proposed mechanism. 相似文献