全文获取类型
收费全文 | 9293篇 |
免费 | 1866篇 |
国内免费 | 1114篇 |
专业分类
化学 | 2912篇 |
晶体学 | 105篇 |
力学 | 102篇 |
综合类 | 51篇 |
数学 | 148篇 |
物理学 | 5023篇 |
无线电 | 3932篇 |
出版年
2024年 | 60篇 |
2023年 | 170篇 |
2022年 | 285篇 |
2021年 | 343篇 |
2020年 | 408篇 |
2019年 | 281篇 |
2018年 | 212篇 |
2017年 | 324篇 |
2016年 | 464篇 |
2015年 | 401篇 |
2014年 | 580篇 |
2013年 | 879篇 |
2012年 | 729篇 |
2011年 | 666篇 |
2010年 | 497篇 |
2009年 | 647篇 |
2008年 | 592篇 |
2007年 | 651篇 |
2006年 | 692篇 |
2005年 | 582篇 |
2004年 | 498篇 |
2003年 | 411篇 |
2002年 | 343篇 |
2001年 | 317篇 |
2000年 | 278篇 |
1999年 | 175篇 |
1998年 | 147篇 |
1997年 | 105篇 |
1996年 | 81篇 |
1995年 | 67篇 |
1994年 | 62篇 |
1993年 | 47篇 |
1992年 | 42篇 |
1991年 | 36篇 |
1990年 | 34篇 |
1989年 | 20篇 |
1988年 | 18篇 |
1987年 | 18篇 |
1986年 | 11篇 |
1985年 | 15篇 |
1984年 | 20篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1977年 | 9篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
We present the explicit form of the symplectic structure of anti-self-dual Yang-Mills (ASDYM) equations in Yang’s J- and K-gauges in order to establish the bi-Hamiltonian structure of this completely integrable system. Dirac’s theory of constraints is applied to the degenerate Lagrangians that yield the ASDYM equations. The constraints are second class as in the case of all completely integrable systems which stands in sharp contrast to the situation in full Yang-Mills theory. We construct the Dirac brackets and the symplectic 2-forms for both J- and K-gauges. The covariant symplectic structure of ASDYM equations is obtained using the Witten-Zuckerman formalism. We show that the appropriate component of the Witten-Zuckerman closed and conserved 2-form vector density reduces to the symplectic 2-form obtained from Dirac’s theory. Finally, we present the Bäcklund transformation between the J- and K-gauges in order to apply Magri’s theorem to the respective two Hamiltonian structures. 相似文献
52.
Sunanda Banerjee Rohini M Godbole Sreerup Raychaudhuri Ben Allanach Sunanda Banerjee Satyaki Bhattacharyya Debajyoti Choudhury Siba Prasad Das Anindya Datta Rohini M Godbole Monoranjan Guchait Sabine Kraml Gobinda Majumdar David Miller Margarete Mühlleitner Nobuchika Okada Maxim Perelstein Santosh K Rai Sreerup Raychaudhuri Saurabh D Rindani DP Roy K Sridhar Rishikesh Vaidya D Zeppenfeld 《Pramana》2006,67(4):617-637
This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology
(WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these
problems by the subgroups formed during the workshop is included in this report. 相似文献
53.
54.
We give an account of the appearance and first developments of the statistical model of atoms proposed by Thomas and Fermi, focusing on the main results achieved by Fermi and his group in Rome. Particular attention is addressed to the unknown contribution to this subject by Majorana, anticipating some important results reached later by leading physicists. 相似文献
55.
Akhlesh Lakhtakia 《Optik》2004,115(4):151-158
57.
介绍未确知数学方法,并用未确知数学方法分析处理物理实验数据,与传统的数据处理方法比较,未确知数学方法不必对数据作任何假设,因此更合理,也更符合实际。 相似文献
58.
59.
Dinesh Topwal U. Manju Sugata Ray S. Raj D. D. Sarma S. R. Krishnakumar M. Bertolo S. La Rosa G. Cautero 《Journal of Chemical Sciences》2006,118(1):87-92
Disordered Sr2FeMoO6 shows a drastic reduction in saturation magnetization compared to highly ordered samples, moreover magnetization as a function
of the temperature for different disordered samples shows qualitatively different behaviours. We investigate the origin of
such diversity by performing spatially resolved photoemission spectroscopy on various disordered samples. Our results establish
that extensive electronic inhomogeneity, arising most probably from an underlying chemical inhomogeneity in disordered samples, is
responsible for the observed magnetic inhomogeneity. It is further pointed out that these inhomogeneities are connected with
composition fluctuations of the type Sr2Fe1+x
Mo1-x
O6 with Fe-rich (x > 0) and Mo-rich (x < 0) regions.
Dedicated to Prof J Gopalakrishnan on his 62nd birthday. 相似文献
60.
本文用准平衡模型分析讨论了线性电压扫描下MIS器件的I/V瞬态.文中除了给出一般的处理方法以外,还给出了几种不同电压扫描率下I/Y特性的计算结果,并与已往的模型作了比较. 相似文献