全文获取类型
收费全文 | 245899篇 |
免费 | 3395篇 |
国内免费 | 605篇 |
专业分类
化学 | 127854篇 |
晶体学 | 3548篇 |
力学 | 9978篇 |
综合类 | 6篇 |
数学 | 30866篇 |
物理学 | 77647篇 |
出版年
2021年 | 2077篇 |
2020年 | 2402篇 |
2019年 | 2552篇 |
2018年 | 3585篇 |
2017年 | 3406篇 |
2016年 | 5330篇 |
2015年 | 3593篇 |
2014年 | 4854篇 |
2013年 | 11892篇 |
2012年 | 9826篇 |
2011年 | 11147篇 |
2010年 | 7663篇 |
2009年 | 7270篇 |
2008年 | 10043篇 |
2007年 | 10003篇 |
2006年 | 9426篇 |
2005年 | 8676篇 |
2004年 | 7965篇 |
2003年 | 6910篇 |
2002年 | 6600篇 |
2001年 | 7221篇 |
2000年 | 5762篇 |
1999年 | 4384篇 |
1998年 | 3507篇 |
1997年 | 3433篇 |
1996年 | 3313篇 |
1995年 | 2987篇 |
1994年 | 2909篇 |
1993年 | 2744篇 |
1992年 | 3129篇 |
1991年 | 3042篇 |
1990年 | 2991篇 |
1989年 | 2725篇 |
1988年 | 2780篇 |
1987年 | 2750篇 |
1986年 | 2573篇 |
1985年 | 3370篇 |
1984年 | 3591篇 |
1983年 | 2927篇 |
1982年 | 3099篇 |
1981年 | 3082篇 |
1980年 | 2889篇 |
1979年 | 2981篇 |
1978年 | 3073篇 |
1977年 | 3065篇 |
1976年 | 3144篇 |
1975年 | 2893篇 |
1974年 | 2879篇 |
1973年 | 3016篇 |
1972年 | 1906篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
971.
A. I. Golovashkin G. N. Izmaïlov G. V. Kuleshova T. Q. Khánh A. M. Tskhovrebov L. N. Zherikhina 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):243-249
A scheme of magnetic calorimeter for registration of rare events
characterized by small energy release (cosmic rays, WIMPs, solitary X-ray
quanta) is proposed. The calorimeter is brought to operation by adiabatic
demagnetization, and its magnetic response is measured by a quantum
interferometer (SQUID, A. Barone and G. Paterno, Physics and applications of Josephson Effect). Special consideration is given to the specific
features of calorimeter operation in the ferromagnetic transition region.
The trigger registration of ultrasmall energy release by a ferromagnetic
system in the metastable state is described. 相似文献
972.
We characterize the sequences of orthogonal polynomials on the unit circle whose derivatives are also orthogonal polynomials on the unit circle. Some relations for the sequences of derivatives of orthogonal polynomials are provided. Finally, we pose some problems about orthogonality-preserving maps and differential equations for orthogonal polynomials on the unit circle. 相似文献
973.
974.
D. Guyomard C. Pagnoux J. J. Zah Letho A. Verbaere Y. Piffard 《Journal of solid state chemistry》1991,90(2)
The single phase compound Na3SbO(PO4)2 was prepared by a solid state reaction. It crystallizes in the orthorhombic system, space group P212121 with a = 6.964(1) Å, b = 9.284(2) Å, c = 12.425(2) Å, Z = 4. The structure was determined from 968 reflections collected on a Nonius CAD4 automatic diffractometer with MoKα radiation. The final R index and weighted Rw index are 0.031 and 0.039, respectively. The structure is built up from strings of corner-sharing SbO6 octahedra to which phosphate groups are linked by two of their vertices. These chains, running parallel to the a-axis, are separated from each other by sodium atoms. 相似文献
975.
976.
977.
978.
The classical Voigt functions occur frequently in a wide variety of problems in astrophysical spectroscopy, emission, absorption
and transfer of radiation in heated atmosphere, and plasma dispersion, and indeed also in the theory of neutron reactions.
Here, in the present paper, by applying several known upper bounds for the first-kind Bessel function J
ν
(x) given recently by (for example) Landau, Olenko and Krasikov, sharp bounding inequalities are obtained for the unified multivariable
Voigt function V
μ,ν
(x; y) in terms of the confluent Fox-Wright function 1ψ0 and its incomplete variant 1ψ0. Connections of the unified multivariable Voigt function V
μ,ν
(x; y) with other unifications and generalizations of the classical Voigt function are also briefly pointed out. 相似文献
979.
D. Boilley A. Marchix B. Jurado K. -H. Schmidt 《The European Physical Journal A - Hadrons and Nuclei》2007,33(1):47-52
We propose a new formula for the saddle-to-scission time that is more general that the one based on Kramers' approach. Its
validity and applicability is then studied in detail. Such a formula is useful for the evaluation of the fission time of very
heavy nuclei. 相似文献
980.
The charge distribution of fragments originatingfrom the fission of the 236U compound nucleus is calculated within a stochastic approach based on Langevin equations. The elongation coordinate, the neck-thickness coordinate, and the charge-asymmetry coordinate are chosen as collective variables. The friction parameter of the charge mode is calculated on the basis of two nuclear-viscosity mechanisms, that of one-body and that of two-body dissipation. It is shown that the Langevin approach is applicable to studying isobaric distributions. In addition, the charge distribution in question is studied as a function of the excitation energy of the compound nucleus and as a function of the coefficient of two-body viscosity. 相似文献