全文获取类型
收费全文 | 159篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
化学 | 45篇 |
晶体学 | 2篇 |
力学 | 2篇 |
物理学 | 127篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 7篇 |
2013年 | 25篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 250 毫秒
81.
Polarized fluorescence spectroscopy is used to investigate the photophysical behavior of poly(p-phenylphenylenevinylene) (PPPV) in polystyrene matrix in comparison with oligomeric model compounds. For this purpose PPPV is modeled by a chain consisting of a distribution of independent oligomeric segments. Excitation energy transfer (EET) between the segments depends on the wavelength of excitation, not only for transfer along an isolated polymer chain, but also for intermolecular transfer at high concentration of PPPV. The spatial range of EET, as indicated by fluorescence depolarization, is reduced for excitation at the long wavelength edge of the absorption spectrum (“red-edge-effect”). © 1995 John Wiley & Sons, Inc. 相似文献
82.
W. S. Weiglhofer 《International Journal of Infrared and Millimeter Waves》1998,19(7):993-1005
Novel expressions for the depolarization dyadics in an axially uniaxial bianisotropic medium (AUBM) are presented. Explicit formulae for the depolarization dyadics are derived for cubical, cylindrical and spherical geometries and their dependence on the magnetoelectric coupling parameter is studied graphically. 相似文献
83.
利用菲涅尔公式分析了Zig—Zag板条中全反射退偏对谐振光束的影响和能量损耗。分析了当谐振光偏振方向与Zig-Zag板条的选偏方向存在偏差时,线偏光经过板条后的偏振态,并计算了各因素对Zig—Zag板条全反射退偏损耗的影响。根据板条全反面的镀膜特点设计合理的谐振光全反射次数可有效地降低Zig—Zag板条的全反射退偏损耗。 相似文献
84.
Raman spectroscopy is widely used for the characterization of bonding type in carbon‐based materials, including carbonized surface layer in ion‐implanted polymers. Studies of the polarization properties of Raman scattering from amorphous carbonaceous materials, however, are very scarce. In this paper, we investigate the polarized Raman spectra of polymethylmethacrylate (PMMA) implanted with 50‐keV Si+ ions at fluences in the range 3.2 × 1014–1.0 × 1017 ions/cm2 and for different visible excitation wavelengths. The spectra of the implanted samples are dominated by the D‐ and G‐bands of sp2 carbon, which evidence strong carbonization of the ion‐modified layer. The multiwavelength excitation allowed us to resonantly probe the depolarization ratios for sp2 clusters of different sizes. We established that the depolarization ratio ρG of the G‐band correlates with the sp2 cluster size approaching the random orientation limit of 0.75 for the smallest clusters and a limiting value of 0.41 for the largest clusters. The experimental findings give evidence for a preferable orientation of the larger size clusters with their hexagonal planes perpendicular to the surface of the sample. A plausible explanation for such an arrangement is that the sp2 clusters form tile‐like arrangements along the ion tracks. This finding may give clues for understanding of the strong transconductance of the ion‐modified layer, and open prospects for the application of polarized Raman spectroscopy as a characterization tool for surface morphology in ion‐implanted materials. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
85.
A general expression that involves only the ranks of the molecular polarizabilties of the two molecules involved in a pair interaction yielding translational and rotational collision‐induced light scattering (CILS) is obtained. It may be used to investigate the behaviour of individual interactions that contribute to the incremental collision‐induced pair polarizability. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
86.
87.
A new circularly polarized (CP) Raman spectrometer is described that demonstrates simultaneous acquisition of all four forms of circular polarization Raman optical activity (ROA). The instrument is a design extension of a commercially available back scattering circular polarization (SCP) ROA spectrometer. Circular polarization of the incident beam is introduced with a quarter‐wave plate, and a half‐wave plate alternately positioned in and out of the beam controls the modulation between right circular polarization (RCP) or left circular polarization (LCP) states. Combining this modulation with the simultaneous detection of RCP and LCP scattered Raman radiation allows the measurement of incident circular polarization (ICP), SCP, in‐phase dual circular polarization(DCPI) and out‐of‐phase DCPII‐ROA. In addition, three different forms of backscattered Raman spectra, namely unpolarized, highly polarized, and depolarized Raman spectra, as well as a degree of circularity spectrum are obtained. The performance of the new all‐CP ROA spectrometer is evaluated with neat α‐pinene and aqueous hen lysozyme solution. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
88.
建立了平均功率激光辐照下,边界主动加热的电光晶体内3维各向异性热传输有限元模型及其热应力双折射模型,在此基础上分析了等离子体普克尔盒热效应。提出了边界主动加热控制电光晶体横向温度梯度热管理思想,并给出平均功率普克尔盒的光开关性能。结果表明:对于50J/10Hz、光束口径为50mm×30mm的激光系统,普克尔盒最大退偏损耗为3.58%,平均退偏损耗为0.9%,波前畸变为1.59λ。采用边界加热控制后,当加热功率密度为500W/m2时,最大退偏损耗为0.17%、平均退偏损耗为0.05%、波前畸变为0.26λ,普克尔盒热效应显著降低,满足设计要求。 相似文献
89.
A. W. Domański D. Budaszewski M. Sierakowski T. R. Woliński 《Opto-Electronics Review》2006,14(4):305-310
In the paper we present results of analysis of partially coherent light depolarization in two types of liquid crystals possessing
linear birefringence controlled by temperature and external electric field changes. Some experimental results of degree of
polarization measurements for different light sources as a superluminescent diode and a laser diode are also presented. 相似文献
90.