全文获取类型
收费全文 | 200篇 |
免费 | 4篇 |
专业分类
化学 | 107篇 |
力学 | 3篇 |
数学 | 5篇 |
物理学 | 89篇 |
出版年
2022年 | 1篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 2篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有204条查询结果,搜索用时 859 毫秒
71.
72.
Space-time correlation functions have been derived for the time-varying intensities of speckle patterns in image space produced by a series of moving random-phase screens. The time-correlation length, which measures the changing rate of intensity fluctuations, is evaluated from the correlation functions to examine the effects of the imaging properties on the temporal behaviour of the speckles resulting from the multiple scattering. It is shown that the average velocity and velocity dispersion of the phase screens can be measured from the time-correlation length by using imaging systems which have a small and a large point spread at the front focal plane of the systems, respectively. Theoretical results for the relationship between the focal position of the imaging lens and the time-correlation length are also presented. 相似文献
73.
74.
Dispersion theory of linear and nonlinear susceptibilities are considered with the aid of complex analysis. 相似文献
75.
The polarized intensity enhancement of the light backscattered multiply from a fractal aggregate of particles is numerically investigated using Monte Carlo simulations. It is confirmed only for the co-polarized intensity component that an effective mean free pathlength lD defined for a fractal medium has the same physical meaning as a mean free pathlength l for a homogeneously random medium. Furthermore, co- and crosspolarized components of the backscattering intensity enhancement decrease in accordance with θ2.16-1.03D and θ4-1.8D in the far-field plane and with ζ0.93D-3.94 and ζ1.07D-3.98 in the boundary plane between the scattering medium and the air. Therefore, the two-dimensional Fourier transform relation is satisfied only between the co-polarized intensity distributions in the far-field and the boundary planes but not the cross-polarized ones with the accuracy of the numerical simulation. Finally, we notice the applicability of the enhanced backscattering light to estimating the dimension of the absorbent fractal medium on the basis of the result that the slope of the intensity decay of the intensity peak is directly proportional to the dimension of the medium but is independent of the absorption. 相似文献
76.
Some properties of diffraction patterns produced by randomized triadic Koch curves are investigated. Randomization is realized by employing Gaussian random numbers for the values of parameters specifying the arrangements of the line segments in a generator of Koch curves. Laser diffraction experiments were performed using the randomized fractals as objects. It is shown that only a slight deviation from the regularity of object fractals causes a considerable degree of randomization in their diffraction patterns. For a sufficient degree of randomization, the diffraction patterns become speckle patterns of unusual appearance. Angular-average intensity distributions obtained experimentally change gradually from a function with many peaks to a relatively smooth function with an increase of randomness of the object fractals. For a sufficiently random object, the angular-average intensity takes the form of the power law as expected. 相似文献
77.
Toshimitsu Yamazaki 《Hyperfine Interactions》1985,21(1-4):85-94
The mesonic aspects of nuclear magnetic moments are discussed with the author's personal proximity and reminiscence. It is emphasized that the observed anomaly in orbitalg factors, traditionally related to the meson exchange effect, may have to be reconsidered from the viewpoint of quark structure of nuclei. 相似文献
78.
The temporal fluctuations in the intensity of light scattered by a moving layer of emulsions and suspensions containing Brownian particles are investigated experimentally, and a comparison is made with light scattered by a translating phase screen. The intensity fluctuations of the scattered light are detected through an imaging system, which collects the light emanating only from a limited volume in the medium. The effect of translational motion of the particle layer on the decay rate of the autocorrelation function of intensity fluctuations depends on the illuminating form of a laser beam and on the point spread function of the imaging system. The Brownian motion of the particles causes the scattered light to fluctuate more rapidly than that arising from the translating phase screen. In the multiple-scattering regime, the influence of this diffusional motion increases with an increase of the particle concentration in the layer. 相似文献
79.
We investigate the phenomenon of the enhanced backscattering of light from soft sediments of fractal clusters. The clusters consist of spherical PMMA particles with the diameter of 0.4 μ, aggregated in aqueous solutions of NaCl. We found that the kinetics of aggregation, which determines the average cluster size in sediments, is controlled by the salt concentration and that the sediments are mutually self-similar media. In comparison to uniform random media, specific features for the enhancement peaks are revealed. It is found that the peak line-shape reflects the particularities of the density of scatterers in a fractal-like medium. It is shown experimentally that the enhancement factor in the light backscattered by fractal aggregated media is sensitive to the average cluster size. On this basis, we suggest a possible way to distinguish between mutually self-similar media. 相似文献
80.
Temporal power spectra of the speckle signal detected by a simple optical fiber probe are analyzed as a function of the laser spot size at a moving scatter plate, the velocity of the plate, the core diameter of the detecting fiber and the numerical aperture of it. The fiber probe is shown to be useful for velocity measurements of the moving scatter plate. 相似文献