全文获取类型
收费全文 | 12577篇 |
免费 | 1525篇 |
国内免费 | 856篇 |
专业分类
化学 | 1404篇 |
晶体学 | 23篇 |
力学 | 702篇 |
综合类 | 164篇 |
数学 | 6646篇 |
物理学 | 2425篇 |
无线电 | 3594篇 |
出版年
2024年 | 33篇 |
2023年 | 96篇 |
2022年 | 165篇 |
2021年 | 218篇 |
2020年 | 263篇 |
2019年 | 258篇 |
2018年 | 271篇 |
2017年 | 384篇 |
2016年 | 450篇 |
2015年 | 359篇 |
2014年 | 618篇 |
2013年 | 922篇 |
2012年 | 768篇 |
2011年 | 704篇 |
2010年 | 681篇 |
2009年 | 729篇 |
2008年 | 777篇 |
2007年 | 833篇 |
2006年 | 763篇 |
2005年 | 695篇 |
2004年 | 607篇 |
2003年 | 533篇 |
2002年 | 525篇 |
2001年 | 481篇 |
2000年 | 415篇 |
1999年 | 387篇 |
1998年 | 303篇 |
1997年 | 272篇 |
1996年 | 228篇 |
1995年 | 196篇 |
1994年 | 141篇 |
1993年 | 113篇 |
1992年 | 107篇 |
1991年 | 97篇 |
1990年 | 69篇 |
1989年 | 60篇 |
1988年 | 47篇 |
1987年 | 50篇 |
1986年 | 45篇 |
1985年 | 53篇 |
1984年 | 53篇 |
1983年 | 20篇 |
1982年 | 36篇 |
1981年 | 22篇 |
1980年 | 20篇 |
1979年 | 26篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1976年 | 11篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
SOI材料的全介质隔离技术与高频互补双极工艺的结合是研制抗辐照能力强、频带宽、速度高的集成运算放大器的理想途径,从实验的角度提出了一种SOI材料全介质隔离与高频互补双极工艺兼容的工艺途径。 相似文献
72.
O. Yu. Dashkova 《Algebra and Logic》2007,46(5):297-302
We are concerned with infinite-dimensional locally soluble linear groups of infinite central dimension that are not soluble
A3-groups and all of whose proper subgroups, which are not soluble A3-groups, have finite central dimension. The structure of groups in this class is described. The case of infinite-dimensional
locally nilpotent linear groups satisfying the specified conditions is treated separately. A similar problem is solved for
infinite-dimensional locally soluble linear groups of infinite fundamental dimension that are not soluble A3-groups and all of whose proper subgroups, which are not soluble A3-groups, have finite fundamental dimension.
__________
Translated from Algebra i Logika, Vol. 46, No. 5, pp. 548–559, September–October, 2007. 相似文献
73.
We study problems of interpolation of positive linear operators in couples of ordered Banach spaces. From this viewpoint, we study couples of noncommutative spaces L 1, L ∞ associated with weights and traces on von Neumann algebras. 相似文献
74.
Juan Pablo Vielma 《Operations Research Letters》2007,35(1):29-35
Two independent proofs of the polyhedrality of the split closure of mixed integer linear program have been previously presented. Unfortunately neither of these proofs is constructive. In this paper, we present a constructive version of this proof. We also show that split cuts dominate a family of inequalities introduced by Köppe and Weismantel. 相似文献
75.
本文提出了一种宽线性共轭梯度算法,分析了算法在均值意义下的收敛性,并给出了算法稳定条件。仿真表明,新算法应用于码分多址系统多址干扰抑制时的性能优于Yin(2003)及Schober(2004)所提出的算法。 相似文献
76.
J. MALINEN O. NEVANLINNA V. TURUNEN Z. YUAN 《数学学报(英文版)》2007,23(4):745-748
Let T be a bounded linear operator in a Banach space, with σ(T)={1}. In 1983, Esterle-Berkani' s conjecture was proposed for the decay of differences (I - T) T^n as follows: Eitheror lim inf (n→∞(n+1)||(I-T)T^n||≥1/e or T = I. We prove this claim and discuss some of its consequences. 相似文献
77.
In this paper, we consider questions related to the structure of inverse matrices of linear bounded operators acting in infinite-dimensional complex Banach spaces. We obtain specific estimates of elements of inverse matrices for bounded operators whose matrices have a special structure. Matrices are introduced as special operator-valued functions on an index set. The matrix structure is described by the behavior of the given function on elements of a special partition of the index set. The method used for deriving the estimates is based on an analysis of Fourier series of strongly continuous periodic functions. 相似文献
78.
Ying Zhang Gang Hu Shigang Chen H.A. Cerdeira 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(3):381-384
A method of controlling global stochasticity in Hamiltonian systems by applying nonlinear perturbation is proposed. With the
well-known standard map we demonstrate that this control method can convert global stochasticity into regular motion in a
wide chaotic region for arbitrary initial condition, in which the control signal remains very weak after a few kicks. The
system in which chaos has been controlled approximates to the original Hamiltonian system, and this approach appears robust
against small external noise. The mechanism underlying this high control efficiency is intuitively explained.
Received 15 January 2002 Published online 6 June 2002 相似文献
79.
Michael Giudici 《Designs, Codes and Cryptography》2006,39(2):163-172
We determine all linear codes C containing the constant code E, for which there is a weight-preserving group of semilinear automorphisms which acts transitively on the set of nontrivial
cosets of E in C.
Michael Giudici - The author holds an Australian Postdoctoral Fellowship. 相似文献
80.
Linear complexity and linear complexity profile are important characteristics of a sequence for applications in cryptography
and Monte-Carlo methods.
The nonlinear congruential method is an attractive alternative to the classical linear congruential method for pseudorandom
number generation.
Recently, a weak lower bound on the linear complexity profile of a general nonlinear congruential pseudorandom number generator
was proven by Gutierrez, Shparlinski and the first author. For most nonlinear generators a much stronger lower bound is expected.
Here, we obtain a much stronger lower bound on the linear complexity profile of nonlinear congruential pseudorandom number
generators with Dickson polynomials. 相似文献