全文获取类型
收费全文 | 717篇 |
免费 | 20篇 |
国内免费 | 2篇 |
专业分类
化学 | 342篇 |
晶体学 | 10篇 |
力学 | 19篇 |
数学 | 140篇 |
物理学 | 228篇 |
出版年
2022年 | 18篇 |
2021年 | 9篇 |
2020年 | 15篇 |
2019年 | 15篇 |
2018年 | 17篇 |
2017年 | 13篇 |
2016年 | 21篇 |
2015年 | 14篇 |
2014年 | 16篇 |
2013年 | 30篇 |
2012年 | 36篇 |
2011年 | 30篇 |
2010年 | 25篇 |
2009年 | 38篇 |
2008年 | 40篇 |
2007年 | 33篇 |
2006年 | 27篇 |
2005年 | 18篇 |
2004年 | 22篇 |
2003年 | 8篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 15篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 18篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1977年 | 19篇 |
1976年 | 16篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 5篇 |
排序方式: 共有739条查询结果,搜索用时 15 毫秒
1.
2.
We present a general scheme for entangling any degree of freedom of two uncorrelated identical particles from independent
sources by a combination of two-particle interferometry and which-way detection. We show that this entanglement generation
procedure works for completely random initial states of the variable to be entangled. We also demonstrate a curious complementarity
exhibited by our scheme and its applications in estimating the generated entanglement as a function of wave packet overlap
at the beamsplitter. 相似文献
3.
4.
We have given design of a very small residual dispersion fiber system consisting of a small dispersion fiber(SDF) with flat modal field and a corresponding dual core coaxial dispersion compensating fiber (DCF). 相似文献
5.
We show by general considerations that it is not possible to test violation of the existing versions of Bell’s inequality
in entangled neutral kaons system using experimentally accessible thin regenerators. We point out the loophole in the recent
argument (A Bramon and M Nowakowski, Phys. Rev. Lett.
83, 1 (1999)) that claimed such a test to be possible. 相似文献
6.
We give a review and a comparison of recent methods of analyzing circular and noncircular optical waveguides. Comparison among competing methodologies is made as follows: Galerkin's method is used with Laguerre-Gauss basis functions in circular geometry to examine the modal solution in a step index fiber, and comparison with the exact solution is made. A W-fiber, which has no exact solution, is then examined. Rectangular geometry is considered, and discussion centers on the use of Galerkin's method using trigonometric basis functions and Hermite-Gauss basis functions. Re difficulty arising from the use of basis functions that do not decay exponentially for large argument (trigonometric functions) is illustrated. Finally, a square step index waveguide is used to illustrate a comparison between a variational method that uses the Gaussian approximation as the starting point, and Galerkin's method using Hermite-Gauss basis functions. We conclude that the variational method does well in predicting the propagation constant β but does not do well in predicting the modal field. 相似文献
7.
We review a little-used but powerful method of solving the scalar wave equation. It uses a modification of the well-known Airy functions, which are easily calculated on desktop computers. The techniques are reminiscent of the WKBJ methodology, but the solution, although approximate, is much more useful than the traditional WKBJ solution and can be used with almost as much ease. Re method is extremely powerful but, to our knowledge, is not used in the optics community. It is useful in analyzing integrated optical waveguide components. 相似文献
8.
From flash photolysis data of benzil and 2,2′-dichlorobenzil, the role of conformeric triplets in the formation of hydrogen
adduct radicals has been discussed. The planar relaxed triplet absorbing at 470 nm is less efficient in forming a hydrogen
adduct radical as compared to its puckered conformeric partner. Among the hydrogen donors, triethyl amine and isopropanol,
the former is more efficient in converting puckered triplets and less efficient in the case of planar conformers. Absorptions
of radicals and radical anions of 2,2′-dichlorobenzil appear at 355 nm and 460 nm respectively. These are blue-shifted as
compared to those of the parent compound benzil appearing at 370 nm and 540 nm, respectively. This blue-shift has been discussed
in terms of steric hindrance due to ortho-substitution. 相似文献
9.
Vijay K. Goyal Rakesh K. Kapania 《International Journal of Solids and Structures》2008,45(10):2799-2817
Because of the inherent complexity of fiber-reinforced laminated composites, it can be challenging to manufacture composite structures according to their exact design specifications, resulting in unwanted material and geometric uncertainties. Thus the understanding of the effect of uncertainties in laminated structures on their static and dynamic responses is highly important for a reliable design of such structures. In this research, we focus on the probabilistic stability analysis of laminated structures subject to subtangential loading, a combination of conservative and nonconservative tangential loads, using the dynamic criterion. In order to study the dynamic behavior by including uncertainties into the problem, three models were developed: exact Monte Carlo simulation, sensitivity-based Monte Carlo simulation, and probabilistic FEA. These methods were integrated into the existing finite element analysis. Also, perturbation and sensitivity analysis have been used to study nonconservative problems to study the stability analysis using the dynamic criterion. 相似文献
10.
P. S. Goyal 《Pramana》2004,63(1):15-24
Inter University Consortium for Department of Atomic Energy Facilities (IUC-DAEF) is an autonomous institute of the University
Grants Commission and provides an interface between the university fraternity and the institutions of Department of Atomic
Energy. Mumbai Centre of IUC-DAEF promotes and supports the use of neutron facilities at Dhruva reactor by the university
scientists. To augment the existing neutron scattering facilities, IUC-DAEF has developed a neutron beam line at Dhruva reactor.
The present paper gives a brief survey of the activities and achievements of Mumbai Centre of IUC-DAEF. 相似文献