全文获取类型
收费全文 | 527814篇 |
免费 | 3099篇 |
国内免费 | 1291篇 |
专业分类
化学 | 246596篇 |
晶体学 | 7396篇 |
力学 | 29856篇 |
综合类 | 9篇 |
数学 | 92307篇 |
物理学 | 156040篇 |
出版年
2020年 | 4531篇 |
2019年 | 5396篇 |
2018年 | 17625篇 |
2017年 | 17539篇 |
2016年 | 15990篇 |
2015年 | 5914篇 |
2014年 | 9405篇 |
2013年 | 19107篇 |
2012年 | 18347篇 |
2011年 | 27405篇 |
2010年 | 19046篇 |
2009年 | 19573篇 |
2008年 | 23256篇 |
2007年 | 25033篇 |
2006年 | 15610篇 |
2005年 | 14874篇 |
2004年 | 14162篇 |
2003年 | 13592篇 |
2002年 | 12840篇 |
2001年 | 12184篇 |
2000年 | 9829篇 |
1999年 | 7265篇 |
1998年 | 6637篇 |
1997年 | 6531篇 |
1996年 | 6092篇 |
1995年 | 5221篇 |
1994年 | 5314篇 |
1993年 | 5325篇 |
1992年 | 5476篇 |
1991年 | 5873篇 |
1990年 | 5731篇 |
1989年 | 5763篇 |
1988年 | 5465篇 |
1987年 | 5484篇 |
1986年 | 5202篇 |
1985年 | 6336篇 |
1984年 | 6678篇 |
1983年 | 5565篇 |
1982年 | 5967篇 |
1981年 | 5547篇 |
1980年 | 5201篇 |
1979年 | 5806篇 |
1978年 | 6038篇 |
1977年 | 6156篇 |
1976年 | 6200篇 |
1975年 | 5827篇 |
1974年 | 5688篇 |
1973年 | 5985篇 |
1972年 | 4636篇 |
1971年 | 4159篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Generic polynomials for the symmetric group S4, the Klein group V4, the cyclic group of order 4, the dihedral group D4, and the alternating group A4 over fields of characteristic 2 are described explicitly. Bibliography: 5 titles.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 330, 2006, pp. 247–258. 相似文献
912.
V. A. Sadovnichy V. V. Alexandrov E. Soto T. B. Alexandrova T. G. Astakhova R. Vega N. V. Kulikovskaya V. I. Kurilov S. S. Migunov N. E. Shulenina 《Journal of Mathematical Sciences》2007,146(3):5938-5947
A mathematical model of the system composed of two sensors, the semicircular canal and the sacculus, is suggested. The model
is described by three lines of blocks, each line of which has the following structure: a biomechanical block, a mechanoelectrical
transduction mechanism, and a block describing the hair cell ionic currents and membrane potential dynamics. The response
of this system to various stimuli (head rotation under gravity and falling) is investigated. Identification of the model parameters
was done with the experimental data obtained for the axolotl (Ambystoma tigrinum) at the Institute of Physiology, Autonomous
University of Puebla, Mexico. Comparative analysis of the semicircular canal and sacculus membrane potentials is presented.
__________
Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 11, No. 7, pp. 207–220, 2005. 相似文献
913.
Testing exponentiality against a class of alternatives which includes the RNBUE distributions based on the empirical laplace transform 总被引:1,自引:0,他引:1
S. G. Meintanis Ya. Yu. Nikitin A. V. Tchirina 《Journal of Mathematical Sciences》2007,145(2):4871-4879
A scale-free test for exponentiality is proposed which is consistent within an extended set of models, including, but not
limited to, the “renewal new better than used in expectation” (RNBUE) class of life distributions. The limiting null distribution of the test statistics is derived, and the approximate local
Bahadur efficiency is calculated for several families of alternatives. Finite-sample properties of the proposed procedures
are investigated via simulation. Bibliography: 24 titles.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 339, 2006, pp. 63–77. 相似文献
914.
Yu-hai WU~ 《中国科学A辑(英文版)》2007,50(7):925-940
This paper concerns the number and distributions of limit cycles in a Z_2-equivariant quintic planar vector field.25 limit cycles are found in this special planar polynomial system and four different configurations of these limit cycles are also given by using the methods of the bifurcation theory and the qualitative analysis of the differential equation.It can be concluded that H(5)≥25=5~2, where H(5)is the Hilbert number for quintic polynomial systems.The results obtained are useful to study the weakened 16th Hilbert problem. 相似文献
915.
916.
Morten Nielsen 《Advances in Computational Mathematics》2007,27(2):195-209
Given a dilation matrix A :ℤd→ℤd, and G a complete set of coset representatives of 2π(A
−Tℤd/ℤd), we consider polynomial solutions M to the equation ∑
g∈G
M(ξ+g)=1 with the constraints that M≥0 and M(0)=1. We prove that the full class of such functions can be generated using polynomial convolution kernels. Trigonometric
polynomials of this type play an important role as symbols for interpolatory subdivision schemes. For isotropic dilation matrices,
we use the method introduced to construct symbols for interpolatory subdivision schemes satisfying Strang–Fix conditions of
arbitrary order.
Research partially supported by the Danish Technical Science Foundation, Grant No. 9701481, and by the Danish SNF-PDE network. 相似文献
917.
V. V. Bilykh 《Journal of Experimental and Theoretical Physics》2007,104(5):814-818
The polarition linewidth is calculated as a function of magnetic field applied perpendicular to the microcavity plane for microcavity excition-polaritons scattered by free electrons in a quantum well. The calculated function exhibits oscillatory behavior; i.e., the scattering rate either increases or decreases with magnetic induction. Possible applications of this effect are discussed. 相似文献
918.
Yen-Shung TSAI 《中国科学A辑(英文版)》2007,50(7):1026-1034
By means of further investigation of solid codes,the problem“Is every fd-domain uni- formly dense”proposed by Yuqi Guo,C.M.Reis and G.Thierrin in 1988 is solved in this paper. 相似文献
919.
920.
We present a study of the temporal compression of nanosecond laser pulses resulting from the coherent control peculiarities of the propagation dynamics in a regime of electromagnetically induced transparency. We describe the general theoretical framework and discuss the crucial conditions required in order to experimentally realize such a temporal compression scheme. A proof-of-concept experimental realization of a scheme of this type in a sample of hot sodium vapors is currently being implemented: we describe in detail the experimental setup designed for this purpose. 相似文献