全文获取类型
收费全文 | 63560篇 |
免费 | 11449篇 |
国内免费 | 10052篇 |
专业分类
化学 | 32253篇 |
晶体学 | 755篇 |
力学 | 2681篇 |
综合类 | 651篇 |
数学 | 5025篇 |
物理学 | 17936篇 |
无线电 | 25760篇 |
出版年
2024年 | 274篇 |
2023年 | 1310篇 |
2022年 | 2054篇 |
2021年 | 2421篇 |
2020年 | 2289篇 |
2019年 | 2220篇 |
2018年 | 2035篇 |
2017年 | 2319篇 |
2016年 | 2615篇 |
2015年 | 3246篇 |
2014年 | 3934篇 |
2013年 | 4905篇 |
2012年 | 5603篇 |
2011年 | 5554篇 |
2010年 | 4700篇 |
2009年 | 4856篇 |
2008年 | 5172篇 |
2007年 | 4534篇 |
2006年 | 4228篇 |
2005年 | 3423篇 |
2004年 | 2625篇 |
2003年 | 2205篇 |
2002年 | 2171篇 |
2001年 | 1932篇 |
2000年 | 1791篇 |
1999年 | 1165篇 |
1998年 | 828篇 |
1997年 | 688篇 |
1996年 | 615篇 |
1995年 | 528篇 |
1994年 | 488篇 |
1993年 | 395篇 |
1992年 | 334篇 |
1991年 | 243篇 |
1990年 | 249篇 |
1989年 | 157篇 |
1988年 | 156篇 |
1987年 | 128篇 |
1986年 | 123篇 |
1985年 | 67篇 |
1984年 | 56篇 |
1983年 | 60篇 |
1982年 | 55篇 |
1981年 | 45篇 |
1980年 | 28篇 |
1979年 | 32篇 |
1978年 | 17篇 |
1977年 | 13篇 |
1974年 | 12篇 |
1925年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
We report on a new type of Fano effect, named as Andreev-Fano effect, in a hybrid normal-metal/supeeconductor (N/S) interferometer embedded with a quantum dot. Compared with the conventional Fano effect, AndreevFano effect has some new features related to the characteristics of Andreev reflection. In the Iinear response regime, the line shape is the square of the conventional Fano shape, while in the nonlinear transport, a sharp resonant structure is superposed on an expanded interference pattern, which is qualitatively different from the conventional Fano effect. The phase dependence of the hybrid N/S interferometer is also distinguished from those of all-N or all-S interferometers. 相似文献
103.
104.
105.
For vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated feedback, there exist several synchronization
types such as synchronizations between total powers and synchronizations between separate polarization modes. Based on the
two-mode rate equations, we study and compare numerically the performances of different synchronization types. Our results
show that three synchronization types exhibit good performances when their synchronization conditions are satisfied. They
are the complete synchronization between total powers, complete synchronization between x-polarized modes, and generalized synchronization between x-polarized and y-polarized modes. The former two types are sensitive to the injection rate and spontaneous emission, while the third type
is contrary. Synchronization type with the best performance may switch from one to another, with changing of injection rate
and spontaneous emission factor. 相似文献
106.
107.
108.
109.
Investigation of remelting and cladding processing with laminar plasma jets on several metals has been conducted looking for possible development of a new surface modification technique. The remelting tests illustrated that the new method could evidently improve the material microstructure and properties of cast iron. The cladding was done with Al2O3 ceramic powder on stainless steel. The energy dispersive spectra (EDS) analysis was used to determine the distribution of the major cladding element in the plasma-processed layers, for which the microstructure observations and hardness measurements were also performed. 相似文献
110.
C.-S. Huang T. Li L. Wei Q.-S. Yan 《The European Physical Journal C - Particles and Fields》2002,23(1):195-199
It is shown that new sources of CP violation can be generated in models with more than one extra dimension. In the supersymmetric models on the space-time , where the radius moduli have auxiliary vacuum expectation values and the supersymmetry breaking is mediated by the Kaluza–Klein
states of the gauge supermultiplets, we analyze the gaugino masses and trilinear couplings for two scenarios and obtain the
result that there exist relative CP violating phases among the gaugino masses and trilinear couplings.
Received: 10 October 2001 / Published online: 20 December 2001 相似文献