全文获取类型
收费全文 | 90篇 |
免费 | 0篇 |
专业分类
化学 | 19篇 |
数学 | 9篇 |
物理学 | 62篇 |
出版年
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2003年 | 4篇 |
2001年 | 2篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有90条查询结果,搜索用时 15 毫秒
71.
本文报导了采用氩离子激光器来泵浦Rr ̄(3+):YLF晶体,应用声光调制器实现了主动锁模;同时应用振动─高反射平面镜也实现了被动锁模,两种锁模均得到了ps光脉冲。据作者了解这是这种晶体材料的第一次锁模运转。 相似文献
72.
73.
Marie Colmont El Mostafa Ketatni Olivier Mentré 《Journal of solid state chemistry》2003,176(1):221-233
The crystal structure of the new Bi∼3Cd∼3.72Co∼1.28O5(PO4)3 has been refined from single crystal XRD data, R1=5.37%, space group Abmm, a=11.5322(28) Å, b=5.4760(13) Å, c=23.2446(56) Å, Z=4. Compared to Bi∼1.2M∼1.2O1.5(PO4) and Bi∼6.2Cu∼6.2O8(PO4)5, this compound is an additional example of disordered Bi3+/M2+ oxyphosphate and is well described from the arrangement of double [Bi4Cd4O6]8+ (=D) and triple [Bi2Cd3.44Co0.56O4]6+ (=T) polycationic ribbons formed of edge-sharing O(Bi,M)4 tetrahedra surrounded by PO4 groups. According to the nomenclature defined in this work, the sequence is TT/DtDt, where t stands for the tunnels created by PO4 between two subsequent double ribbons and occupied by Co2+. The HREM study allows a clear visualization of the announced sequence by comparison with the refined crystal structure. The Bi3+/M2+ statistic disorder at the edges of T and D entities is responsible for the PO4 multi-configuration disorder around a central P atom. Infrared spectroscopy and neutron diffraction of similar compounds (without the highly absorbing Cadmium) even suggests the long range ordering loss for phosphates. Therefore, electron diffraction shows the existence of a modulation vector q*=1/2a*+(1/3+ε)b* which pictures cationic ordering in the (001) plane, at the crystallite scale. This ordering is largely lost at the single crystal scale. The existence of mixed Bi3+/M2+ positions also enables a partial filling of the tunnels by Co2+ and yields a composition range checked by solid state reaction. The title compound can be prepared as a single phase and also the M=Zn2+ term can be obtained in a biphasic mixture. For M=Cu2+, a monoclinic distortion has been evidenced from XRD and HREM patterns but surprisingly, the orthorhombic ideal form can also be obtained in similar conditions. 相似文献
74.
Marie Colmont El Mostafa Ketatni Olivier Mentré 《Journal of solid state chemistry》2006,179(7):2111-2119
Two solid solutions BiMxMg(2−x)PO6 (with M2+=Zn or Cd) have been studied through 31P MAS NMR. The analysis has been performed on the basis of refined crystal structures through X-ray diffraction and neutron diffraction. The BiZnxMg(2−x)PO6 does not provide direct evidence for sensitive changes in the phosphorus local symmetry. This result is in good agreement with structural data which show nearly unchanged lattices and atomic separations through the Zn2+ for Mg2+ substitution. On the other hand, the Cd2+ for Mg2+ substitution behaves differently. Indeed, up to five resonances are observed, each corresponding to one of the five first-cationic neighbour distributions, i.e. 4Mg/0Cd, 3Mg/1Cd, 2Mg/2Cd, 1Mg/3Cd and 0Mg/4Cd. Their intensities match rather well the expected weight for each configuration of the statistical Cd2+/Mg2+ mixed occupancy. The match is further improved when one takes into account the influence of the 2nd cationic sphere that is available from high-field NMR data (18.8 T). Finally, the fine examination of the chemical shift for each resonance versus x allows to de-convolute the mean Z/a2 effective field into two sub-effects: a lattice constraint-only term and a chemical-only term whose effects are directly quantifiable. 相似文献
75.
76.
Alves GA Amato S Anjos JC Appel JA Astorga J Bracker SB Cremaldi LM Dagenhart WD Darling CL Dixon RL Errede D Fenker HC Gay C Green DR Jedicke R Karchin PE Kennedy C Kwan S Lueking LH de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A Passmore D Rafatian A dos Reis AC Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wallace A Wu Z 《Physical review letters》1996,77(12):2392-2395
77.
78.
79.
80.