全文获取类型
收费全文 | 23450篇 |
免费 | 713篇 |
国内免费 | 63篇 |
专业分类
化学 | 15058篇 |
晶体学 | 381篇 |
力学 | 729篇 |
综合类 | 1篇 |
数学 | 1815篇 |
物理学 | 6242篇 |
出版年
2023年 | 242篇 |
2022年 | 578篇 |
2021年 | 540篇 |
2020年 | 597篇 |
2019年 | 718篇 |
2018年 | 657篇 |
2017年 | 635篇 |
2016年 | 927篇 |
2015年 | 648篇 |
2014年 | 1070篇 |
2013年 | 1934篇 |
2012年 | 1580篇 |
2011年 | 1697篇 |
2010年 | 1114篇 |
2009年 | 942篇 |
2008年 | 1135篇 |
2007年 | 1110篇 |
2006年 | 878篇 |
2005年 | 768篇 |
2004年 | 604篇 |
2003年 | 466篇 |
2002年 | 424篇 |
2001年 | 254篇 |
2000年 | 245篇 |
1999年 | 183篇 |
1998年 | 127篇 |
1997年 | 154篇 |
1996年 | 178篇 |
1995年 | 170篇 |
1994年 | 165篇 |
1993年 | 180篇 |
1992年 | 218篇 |
1991年 | 156篇 |
1990年 | 146篇 |
1989年 | 161篇 |
1988年 | 135篇 |
1987年 | 134篇 |
1986年 | 115篇 |
1985年 | 168篇 |
1984年 | 186篇 |
1983年 | 134篇 |
1982年 | 144篇 |
1981年 | 134篇 |
1980年 | 142篇 |
1979年 | 145篇 |
1978年 | 149篇 |
1977年 | 133篇 |
1976年 | 95篇 |
1975年 | 92篇 |
1974年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
We discuss the nature of the pairing mechanism and the physical properties associated with the normal as well as the superconducting state of cubic perovskites Ba0.6K0.4BiO3using the strong coupling theory. An interaction potential which includes the Coulomb, electron–optical phonon and electron–plasmon interactions is developed to elucidate the superconducting state. A model dielectric function is constructed with these interactions fulfilling thef-sum rule. The screening parameter (μ* = 0.26) infers the poor screening of charge carriers. The electron–optical phonon strength (λ) estimated as 0.98 is consistent with an attractive electron–electron interaction and supports the moderate to strong coupling theory. The superconducting transition temperature of Ba0.6K0.4BiO3is then estimated as 32 K. Ziman's formula of resistivity is employed to analyse and compare this with the temperature-dependent resistivity of a single crystal. The estimated contribution from the electron–optical phonon together with the residual resistivity clearly infers a difference when a comparison is made with experimental data. The subtracted data infer a quadratic temperature dependence in the temperature domain (30 ≤ T ≤ 200 K). The quadratic temperature dependence of ρ [ = ρexp − (ρ0 + ρe–ph)] is understood in terms of 3D electron–electron inelastic scattering. The presence of these el–el and el–ph interactions allows a coherent interpretation of the physical properties. Analysis reveals that a moderate to strong coupling exists in the Ba0.6K0.4BiO3system and the coupling of electrons with the high-energy optical phonons of the oxygen breathing mode will be a reason for superconductivity. The implications of the above analysis are discussed. 相似文献
82.
83.
Triorganotin(IV) and triorganolead(IV) derivatives of the types Me3Sn(SCZ) and Ph3Pb(SCZ) (where SCZ? is the anion of a semicarbanzone ligand) have been synthesized by substitution reactions of trimethyltin chloride and triphenyl-lead chloride with semicarbazones derived from heterocyclic ketones. The resulting complexes have been characterized by elemental analyses, molecualr weight determinations and conductivity measurements. The mode of bonding has been established on the basis of infrared and 1H, 13C and 119Sn NMR spectroscopic studies. Some respresentative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria; the results of these investigations have been reported in the present paper. 相似文献
84.
Koijam Manihar Singh K. S. Bhamra 《International Journal of Theoretical Physics》1990,29(9):1015-1029
The dynamics of a radiating viscous fluid universe coupled with zero-mass scalar field is investigated in the Einstein formalism and two exact solutions are obtained. Both the solutions give expanding models. Their many physical and geometrical properties are studied. The model universe corresponding to the first solution turns out to be a big bang model. The second model shows an interesting feature of absorbing radiation rather than emitting it under certain conditions. 相似文献
85.
Anjos JC Appel JA Bean A Bracker SB Browder TE Cremaldi LM Duboscq JE Elliott JR Escobar CO Gibney MC Hartner GF Karchin PE Kumar BR Losty MJ Luste GJ Mantsch PM Martin JF McHugh S Menary SR Morrison RJ Nash T Ong P Pinfold J Punkar G Purohit MV Santoro AF Sidhu JS Sliwa K Sokoloff MD Souza MH Spalding WJ Streetman ME Stundia AB Witherell MS 《Physical review letters》1990,64(24):2885-2888
86.
87.
88.
89.
90.