全文获取类型
收费全文 | 104篇 |
免费 | 0篇 |
专业分类
化学 | 41篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 1篇 |
物理学 | 58篇 |
出版年
2023年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 6篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1972年 | 1篇 |
排序方式: 共有104条查询结果,搜索用时 15 毫秒
81.
82.
We investigate experimentally and numerically a novel method of modifying photorefractive waveguides in a lithium niobate crystal by a guided beam. The guided beam with a strong optical power can change the refractive index of the photorefractive waveguide because of the photorefractive effect. The modification of waveguide structure can be utilized for optical dynamic interconnection. Changes of optical characteristics of a probe beam caused by a modification beam are investigated. Experimental results show that the transmitted power or the peak intensity of the probe beam decreases exponentially as a function of total exposure energy of the modification beam. We also numerically analyze the refractive index change caused by the modification beam in the photorefractive waveguide. The numerical results show good agreement with the experimental results. 相似文献
83.
S. Matsuki S. Nakamura M. Hyakutake M. Matoba Y. Yoshida I. Kumabe 《Nuclear Physics A》1973,201(3):608-620
The energy levels of 91Nb were studied by means of the (p, nγ) reaction. The de-excitation γ-rays were observed with a Ge(Li) detector in the proton energy range from 3.25 to 5.51 MeV in steps of about 30 keV. Resonances attributed to isobaric analog states in the compound system 91Nb were observed in the excitation functions of the de-excitation γ-rays. From an analysis of these analog resonances, a Hauser-Feshbach analysis and the γ-decay scheme, the spin-parities of the levels up to 2792.6 keV (22 levels) were assigned. 相似文献
84.
85.
86.
To extract effectively the absorber information embedded in a homogeneous scattering medium in the transmission geometry, a method of taking the ratio of the output intensity in a measured medium to that in a reference medium is evaluated. The reference medium is a virtual one with the same scattering coefficient distribution as that of the measured medium, but with a uniform absorption coefficient distribution. Numerical results show that the proposed method can enhance the output signal by extracting the ballistic-like component. We also apply a backprojection method to reconstruct the single absorber using many pairs of input and output intensity ratio distributions. The reconstruction position error and the quantitative measurement of absorption coefficient are discussed. 相似文献
87.
88.
Arif Yanuar Ridwan Ryuta Matoba Jing Wu Jae-Hoon Choi Hirofumi Hirai Hirokazu Kawagishi 《Tetrahedron letters》2018,59(26):2559-2561
Nine compounds including a new cinnamamide (1), N-(1-cinnamoylpyrrolidin-2-yl)cinnamamide, and two compounds (8 and 9) first isolated from natural sources, were obtained from the edible mushroom Pholiota lubrica. Their structures were determined by the interpretation of spectroscopic data. Compounds 1, 3 and 9 exhibited the inhibitory activity against lettuce, while compounds 2 and 7 promoted the growth of lettuce. 相似文献
89.
Nobuatsu Tanaka 《国际流体数值方法杂志》1999,30(8):957-976
A simple, efficient, flexible and accurate interpolation method, CIVA, is introduced for use with mesh‐free methods for flow simulations. The method enables mesh‐free cubic interpolation with the local co‐ordinate system, such as volume and area co‐ordinates, by utilizing the concept of the CIP scheme and allows the development of new highly accurate mesh‐free methods. The mesh‐free methods integrate the gridless, particle and CIP methods since they have flexibility in the treatment of moving calculation points. For achieving high accuracy with the CIVA method, it is also important to correctly evaluate particle movement. The improvement of the evaluating algorithm is another objective of this study. The validity of the algorithms is confirmed by applying them to the convection and convection–diffusion problems. Since the CIVA‐based mesh‐free methods enable flexible, efficient and accurate fluid simulation, they make it possible to perform highly accurate simulations of many kinds of problems that involve complicated geometries and phenomena. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
90.
Nobuatsu Tanaka 《国际流体数值方法杂志》2000,34(5):403-424
This is the second report on the development of a highly accurate interpolation method, which is called cubic interpolation with volume/area (CIVA) co‐ordinates, for mesh‐free flow simulations. In this paper, the method of determining the c‐parameter of CIVA using a constant curvature condition is first considered for the two‐ and three‐dimensional cases. A computation of a three‐dimensional passive scalar advection problem is performed for accuracy verification and for comparison with widely used methods. Then, an application algorithm of the CIVA method respecting incompressible fluid simulation is presented. As the incompressible condition based on Lagrangian approaches causes problems, in this paper we consider the condition based on the conventional Eulerian approach. The CIVA‐based incompressible flow simulation algorithm enables a highly accurate simulation of many kinds of problems that have complicated geometries and involve complicated phenomena. To confirm the facts, numerical analyzes are executed for some benchmark problems, namely flow in a square cavity, free surface sloshing and moving boundary problems in complex geometries. The results show that the method achieves high accuracy and has high flexibility, even for the flows involving high Reynolds number, complicated geometries, moving boundaries and free surfaces. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献