全文获取类型
收费全文 | 416244篇 |
免费 | 21317篇 |
国内免费 | 10989篇 |
专业分类
化学 | 244952篇 |
晶体学 | 6202篇 |
力学 | 19682篇 |
综合类 | 539篇 |
数学 | 42529篇 |
物理学 | 134646篇 |
出版年
2022年 | 5086篇 |
2021年 | 5680篇 |
2020年 | 6304篇 |
2019年 | 6317篇 |
2018年 | 6253篇 |
2017年 | 5980篇 |
2016年 | 9576篇 |
2015年 | 7870篇 |
2014年 | 10371篇 |
2013年 | 20602篇 |
2012年 | 18435篇 |
2011年 | 20839篇 |
2010年 | 14057篇 |
2009年 | 13751篇 |
2008年 | 16921篇 |
2007年 | 16300篇 |
2006年 | 15463篇 |
2005年 | 13672篇 |
2004年 | 11687篇 |
2003年 | 10311篇 |
2002年 | 9812篇 |
2001年 | 11745篇 |
2000年 | 9068篇 |
1999年 | 7816篇 |
1998年 | 6191篇 |
1997年 | 6191篇 |
1996年 | 6219篇 |
1995年 | 5523篇 |
1994年 | 5393篇 |
1993年 | 4816篇 |
1992年 | 5538篇 |
1991年 | 5443篇 |
1990年 | 5088篇 |
1989年 | 4852篇 |
1988年 | 4651篇 |
1987年 | 4589篇 |
1986年 | 4313篇 |
1985年 | 5485篇 |
1984年 | 5459篇 |
1983年 | 4462篇 |
1982年 | 4606篇 |
1981年 | 4408篇 |
1980年 | 4293篇 |
1979年 | 4601篇 |
1978年 | 4961篇 |
1977年 | 4710篇 |
1976年 | 4619篇 |
1975年 | 4400篇 |
1974年 | 4315篇 |
1973年 | 4368篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
T. Nakamura 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):33-37
We present the recent experimental results on the 6He structure studied by the 6Li(t, 3He)6He reaction at 336 MeV. Above the conspicuous peaks for ground and first excited states for 6He, we have observed a broad structures at E
x∼ 5 MeV, and E
x∼ 15 MeV. The angular distribution of this structure exhibits the dominance of a ΔL = 1 transition, indicating the existence of intruder dipole states at low excitation energies in 6He. A slight admixture of positive-parity states in this structure has been indicated as well.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
992.
993.
994.
Electronic properties of model quantum-dot structures in zero and finite magnetic fields 总被引:1,自引:0,他引:1
H. Saarikoski E. Räsänen S. Siljamäki A. Harju M.J. Puska R.M. Nieminen 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(2):241-252
We have computed electronic structures and total energies of circularly confined two-dimensional quantum dots and their lateral
dimers in zero and finite uniform external magnetic fields using different theoretical schemes: the spin-density-functional
theory (SDFT), the current-and-spin-density-functional theory (CSDFT), and the variational quantum Monte Carlo (VMC) method.
The SDFT and CSDFT calculations employ a recently-developed, symmetry-unrestricted real-space algorithm allowing solutions
which break the spin symmetry. Results obtained for a six-electron dot in the weak confinement limit and in zero magnetic
field as well as in a moderate confinement and in finite magnetic fields enable us to draw conclusions about the reliability
of the more approximative SDFT and CSDFT schemes in comparison with the VMC method. The same is true for results obtained
for the two-electron quantum dot dimer as a function of inter-dot distance. The structure and role of the symmetry-breaking
solutions appearing in the SDFT and CSDFT calculations for the above systems are discussed.
Received 16 October 2001 and Received in final form 17 January 2002 相似文献
995.
996.
997.
P. Paasche T. Valenzuela D. Biswas C. Angelescu G. Werth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):295-300
We have examined experimentally the motional spectrum of an electron cloud confined in a Penning trap. When the axial oscillation
is excited by a radio frequency field the resonance exhibits a double structure. Both components depend differently on the
number of trapped electrons and have different shape and width. We conclude that one of them corresponds to the excitation
of the individual electrons while the other is the center-of-mass mode of the cloud. The threshold behaviour of the center-of-mass
resonance suggests that it is a parametric instability of a Mathieu type equation of motion.
Received 11 July 2001 and Received in final form 12 November 2001 相似文献
998.
999.
1000.