全文获取类型
收费全文 | 130篇 |
免费 | 8篇 |
国内免费 | 7篇 |
专业分类
化学 | 31篇 |
综合类 | 1篇 |
数学 | 4篇 |
物理学 | 109篇 |
出版年
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 15篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 13篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1988年 | 2篇 |
排序方式: 共有145条查询结果,搜索用时 281 毫秒
1.
In-plane single domain and vortex magnetization configurations of the magnetic dot in the hybrid superconductor–ferromagnet system are considered. Single domain configuration energy shift due to the presence of superconductor is calculated. The change of the phase curve of the ferromagnetic dot magnetization due to the repulsion of the magnetic field by the superconductor is obtained. Up to the two-fold decrease of the ferromagnetic dot critical radius due to the presence of the superconductor is predicted. 相似文献
2.
The effect of an applied magnetic field on an inhomogeneous superconductor is studied and the value of the upper critical magnetic field Hc3 at which superconductivity can nucleate is estimated. In addition, the authors locate the concentration of the order parameter, which depends on the inhomogeneous term a(x). Unlikely to the homogeneous case, the order parameter may concentrate in the interior of the superconducting material, due to the influence of the inhomogeneous term a(x). 相似文献
3.
The structural phase transition from orthorhombic (T) phase to tetragonal (T′) phase in substituted La2−x
R
x
CuO4 (R = Pr, Nd, Sm, Eu and Gd) and T′ to T-phase in Pr2−x
M
x
CuO4−y
(M = Sr, Ca) has been studied by X-ray diffraction technique. The T-phase of La2CuO4 is transferred to T′ phase abruptly atx=0.8, 0.4, 0.4, 0.3 and 0.4 respectively for substitution of Pr, Nd, Sm, Eu and Gd for La in La2CuO4 without evidence of the T* phase. The T′ structure of Pr2CuO4 (x = 0.0) gets transformed to the T* structure at 30% Ca doping (x=0.6) and then to the T structure at 50% Ca doping (x=1.0), while for Sr-contentx=0.0, 0.4 and 1.0 it shows T′, T* and T structure respectively. 相似文献
4.
Due to the Meissner effect, a permanent magnet is levitated, when released above a high temperature superconductor. When there is an inhomogeneous temperature field around the magnet, the magnet might start to oscillate with increasing amplitude until it remains in a continuous rotation. A mathematical model for the described effect is presented which couples heat transfer and electromagnetic forces with the equation of motion, yielding to a multiphysics task. In a detailed analysis it is found, that the torque which drives the rotation of the magnet, is explicitly given in terms of Bessel functions and the Fourier coefficients of order zero and one of the temperature field of the surrounding air. 相似文献
5.
介绍了一套制冷机冷却型小型超导强磁场系统。超导磁体线圈用铌钛超导线绕制,室温孔直径为75mm,磁场中心Φ25mm×250mm区域内最高场强达到3.64T,磁场不均匀性小于3%。在2.62T场强下连续闭环运行了20天,电流衰减率近似为零。采用4K级低温制冷机冷却防辐射冷屏,液氦蒸发率小于0.03升/小时,系统一次可注入液氦50升,补液周期大于60天。 相似文献
6.
T. Tsuneta T. Toshima K. Inagaki T. Shibayama S. Tanda S. Uji M. Ahlskog P. Hakonen M. Paalanen 《Current Applied Physics》2003,3(6):473-476
We succeed in synthesizing NbSe2 nanotubes along with nanofibers by chemical vapor transportation. They are stable crystalline systems and can be synthesized reproducibly in a nearly equilibrium reacting process. We have investigated these nanosize structures of NbSe2 by transmission electron microscopy and electron diffraction. Both of the structures have a similar size of 100–200 nm in diameter. While nanotubes consist of rolled-up NbSe2 layers, nanofibers are a pile of thin flat layers. We propose a mechanism of the formation of NbSe2 nanotubes and nanofibers on the basis of deseleniditive transition from a NbSe3 fiber-shaped crystal. We also measured electrical resistance of the nanofibers with conductive atomic force microscopy and demonstrated that the material show metallic behavior at room temperature. 相似文献
7.
8.
Crystalline samples of La3Ni2B2N3 were synthesized using solid state metathesis reactions from combinations of La, LaCl3, NiCl2 together with Li3BN2. The structure was determined by single crystal X‐ray diffraction (I4/mmm (No. 139), a = 372.95(2) pm, c = 2056.3(2) pm, R1 = 0.027, wR2 = 0.062) and confirmed earlier results from neutron powder diffraction. La3Ni2B2N3 contains BN units capping square planar Ni layers. Isolated nitrogen atoms reside in La6 octahedra. Magnetic measurements on several bulk samples exhibit superconductivity at temperatures below 14.6 K. 相似文献
9.
10.