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排序方式: 共有758条查询结果,搜索用时 31 毫秒
751.
G.E. Grechnev A.S. Panfilov A.V. Fedorchenko V.A. Desnenko S.L. Gnatchenko V. Tsurkan J. Deisenhofer A. Loidl D.A. Chareev O.S. Volkova A.N. Vasiliev 《Journal of magnetism and magnetic materials》2012
Magnetization studies were carried out for the novel FeSe1−xTex superconductors (0≤x≤1) to investigate a behavior of the intrinsic magnetic susceptibility χ in the normal state. The magnetic susceptibility was found to increase gradually with Te content. The temperature dependencies of the magnetic susceptibility χ and its anisotropy Δχ=χ∥−χ⊥ were measured for FeSe in the temperature range 4.2–300 K, and a growth of susceptibility with temperature was revealed. For FeTe a substantial increase of χ under pressure was found. Ab initio calculations of the band structure and magnetic susceptibility have shown, that FeSe1−xTex systems are close to magnetic instability with dominating enhanced spin paramagnetism. The calculated paramagnetic susceptibility exhibits a strong dependence on the unit cell volume V and especially the height of chalcogen species from the Fe plane. With appropriate values of these parameters the calculations have reproduced the experimental data on χ(T) and χ(P) for FeSe and FeTe, respectively. 相似文献
752.
In order to determine the key parameters that control the resistive switching mechanism in metal–complex oxides interfaces, we have studied the electrical properties of metal/YBa2Cu3O7−δ (YBCO) interfaces using metals with different oxidation energy and work function (Au, Pt, Ag) deposited by sputtering on the surface of a YBCO ceramic sample. By analyzing the IV characteristics of the contact interfaces and the temperature dependence of their resistance, we inferred that ion migration may generate or cancel conducting filaments, which modify the resistance near the interface, in accordance with the predictions of a recent model. 相似文献
753.
简述了高温超导体的特点,系统介绍了第二代高温超导体的研究状况、制备工艺,并分析了第二代高温超导体在核聚变领域的应用前景。 相似文献
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B. A. Albiss I. M. Obaidat M. Gharaibeh W. Hatamleh S. A. Barhoum M. K. Hasan 《Crystal Research and Technology》2009,44(9):930-936
The magnetic and transport properties of polycrystalline YBa2 (Cu1‐xMx)3 O7‐δ (M = B and Mn) superconductor was investigated. Samples of YBa2(Cu1‐xBx)3O7‐δ doped with several concentrations of boron B(x = 0.05 and 0.1) were investigated using magnetization measurements. A YBa2(Cu1‐xMnx)3O7‐δ sample doped with Mn with concentration of x = 0.02 was investigated using current‐voltage (I‐V) measurements. Our results on the YBa2(Cu1‐xBx)3O7‐δ samples reveal a considerable increase in the hysterisis width of the magnetization, M versus the applied magnetic field H with increasing boron concentration. The lower critical field was also found to be enhanced by boron doping. The critical current density, Jc was found to be significantly enhanced in the Mn‐doped sample. The enhancement of Jc was found to be more significant at the lower temperatures for all applied magnetic fields used (0 Oe, 300 Oe, and 500 Oe). Thus, chemical doping is suggested to enhance the vortex pinning forces in the YBCO samples. From the resistivity (R‐T) measurements, chemical doping of the samples was found to have no significant effect on the critical temperature, Tc. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
757.
因双根并绕堆叠结构的 YBCO 带材能够进一步增加设备承载电流密度, 被广泛应用于大型超导设备线圈绕制中. 本文研究了外层有包绕绝缘的双根并绕堆叠 YBCO 带材有缺陷情况下的失超传播特性, 应用有限元法方法, 建立了双根 YBCO 带材堆叠状态下失超仿真模型, 研究了存在不同缺陷的情况下双根堆叠超导带材的失超传播特性, 探索了堆叠带材在不同工作电流下传播速度(NZPV) 等参数的变化趋势, 同时探究了不同铜稳定层厚度下并绕堆叠带材失超传播规律. 结果表明缺陷区域面积增加以及铜稳定层厚度减小, 都将导致双根并绕堆叠结构的二代高温超导带材失超传播速度增加, 在带材上的温升增加, 增加失超的风险. 研究结果可以为超导设备安全稳定运行参数设置提供支持. 相似文献
758.