全文获取类型
收费全文 | 596篇 |
免费 | 82篇 |
国内免费 | 15篇 |
专业分类
化学 | 18篇 |
晶体学 | 1篇 |
力学 | 23篇 |
综合类 | 12篇 |
数学 | 438篇 |
物理学 | 201篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 7篇 |
2018年 | 15篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 17篇 |
2014年 | 34篇 |
2013年 | 60篇 |
2012年 | 28篇 |
2011年 | 38篇 |
2010年 | 29篇 |
2009年 | 34篇 |
2008年 | 32篇 |
2007年 | 48篇 |
2006年 | 41篇 |
2005年 | 40篇 |
2004年 | 44篇 |
2003年 | 22篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 12篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 13篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有693条查询结果,搜索用时 31 毫秒
621.
本文改进了文[1]的结果,利用体上矩阵的初等行和列变换,给出了任意体上的矩阵方程AmsXas=Bms的一种更为实用的简便解法。 相似文献
622.
We propose here a new optical modified signed-digit (MSD) adder module based on bit plane pattern encoding of MSD digits and pattern operations. The pattern operations required in the algorithm are duplication, combination and shifting. They are simply performed by using optical components such as beam splitters, mirrors and parallel plates, instead of optical logic arrays. An optical MSD adder module comprised of six properly interacting blocks with all optical components packaged on a common substrate is presented in detail. We analyze the system errors caused by manufacture and alignment of optical components, the information throughput, the intensity nonuniformity and the system volume of the adder module. 相似文献
623.
根据振荡电路产生不同周期的计时信号,对打点计时器的供电电源进行了改进。改进后,实验者可根据不同的运动速度来选择适宜的打点计时单位,使纸带上的点疏密程度较为合理,从而减少测量误差。 相似文献
624.
625.
626.
Experimental results on the multiplicative orders of Gauss periods in finite fields are presented. These results indicate that Gauss periods have high order and are often primitive (self-dual) normal elements in finite fields. It is shown that Gauss periods can be exponentiated in quadratic time. An application is an efficient pseudorandom bit generator.
627.
628.
Neeta Singh 《Proceedings of the American Mathematical Society》1996,124(8):2561-2569
We prove the existence and nontriviality of tertiary exotic characteristic classes extending the results of Peterson and Ravenel for secondary exotic classes.
629.
Gerrit Coddens 《Foundations of Physics Letters》1995,8(3):261-277
We give a simple deductive derivation of the Dirac equation for a free particle. Our construction provides a clear distinction between what are the physical contents and what are purely mathematical expedients in the formalism of quantum mechanics (QM). 相似文献
630.
Information processing in nonlinear neural networks with a finite numberq of stored patterns is studied. Each network is characterized completely by its synaptic kernelQ. At low temperatures, the nonlinearity typically results in 2q–2–q metastable, pure states in addition to theq retrieval states that are associated with theq stored patterns. These spurious states start appearing at a temperature
, which depends onq. We give sufficient conditions to guarantee that the retrieval states bifurcate first at a critical temperatureT
c
and that
/T
c
0 asq. Hence, there is a large temperature range whereonly the retrieval states and certain symmetric mixtures thereof exist. The latter are unstable, as they appear atT
c
. For clipped synapses, the bifurcation and stability structure is analyzed in detail and shown to approach that of the (linear) Hopfield model asq. We also investigate memories that forget and indicate how forgetfulness can be explained in terms of the eigenvalue spectrum of the synaptic kernelQ. 相似文献