全文获取类型
收费全文 | 1068篇 |
免费 | 513篇 |
国内免费 | 117篇 |
专业分类
化学 | 121篇 |
晶体学 | 11篇 |
力学 | 120篇 |
综合类 | 30篇 |
数学 | 111篇 |
物理学 | 1305篇 |
出版年
2024年 | 1篇 |
2023年 | 10篇 |
2022年 | 34篇 |
2021年 | 36篇 |
2020年 | 41篇 |
2019年 | 25篇 |
2018年 | 33篇 |
2017年 | 43篇 |
2016年 | 33篇 |
2015年 | 48篇 |
2014年 | 121篇 |
2013年 | 101篇 |
2012年 | 82篇 |
2011年 | 85篇 |
2010年 | 105篇 |
2009年 | 115篇 |
2008年 | 86篇 |
2007年 | 76篇 |
2006年 | 88篇 |
2005年 | 82篇 |
2004年 | 71篇 |
2003年 | 64篇 |
2002年 | 64篇 |
2001年 | 55篇 |
2000年 | 46篇 |
1999年 | 16篇 |
1998年 | 20篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 9篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1976年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有1698条查询结果,搜索用时 15 毫秒
121.
V. V. Azharonok I. I. Filatova I. V. Voshchula V. A. Dlugunovich O. V. Tsaryuk T. N. Gorzhanova 《Journal of Applied Spectroscopy》2007,74(4):465-471
We have used laser Stokes polarimetry to study changes in the structure of paper for offset printing when exposed to a high-frequency
electromagnetic field. We have shown that the effect of a high-frequency electromagnetic field on paper appears as a decrease
in the structural ordering of the material and a change in the shape of the indicatrix of the reflected radiation power from
an He-Ne laser at the wavelength 632.8 nm, a decrease in the bidirectional reflection and transmission coefficients of the
paper. We have established that when the force lines of the magnetic component of the high-frequency electromagnetic field
are oriented perpendicular to the plane of the sheet of paper, we observe a more substantial decrease in the anisotropy in
the surface layer and within the interior (the volume) of the paper than when the lines of force are oriented parallel to
the plane of the paper.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 4, pp. 421–426, July–August, 2007. 相似文献
122.
Mohsen Timoumi 《Reports on Mathematical Physics》2004,54(1):1-21
In this paper we study in some particular cases, the existence and multiplicity of closed trajectories of a relativistic particle moving in some electromagnetic fields. To solve this problem, we use Hamiltonian systems and variational methods. 相似文献
123.
A potential for the bounded part of the Maxwell tensor associated to the Liénard-Wiechert field has been obtained by van Weert.
In this paper we explicitly derive the non-local potential for the radiative part of such a tensor. 相似文献
124.
In this work, we are interested in the numerical approximation of an eigenvalue problem arising from the computation of guided modes in integrated optics waveguides which are particular cases of open waveguides. 相似文献
125.
126.
127.
铈对纳米铁氧体粉末电磁学性质影响的研究 总被引:12,自引:1,他引:11
采用固相反应制备的Ce0 .2 5FeNiO3,FeNiO5,Fe3O4 ,Fe2 O34种纳米粉体 ,在 1~ 2 0 0 0MHz范围内进行了电磁学性质 (μ′,μ″ ,ε′,ε″)及吸波特性的比较研究。发现 4种纳米粉体的 μ′数据大小顺序为Ce0 .2 5FeNiO3>FeNiO5>Fe3O4 >Fe2 O3,μ″的变化幅度为Ce0 .2 5FeNiO3>Fe3O4 >FeNiO5>Fe2 O3。Ce0 .2 5FeNiO3的ε′和ε″的变化幅度大于其他几种纳米粉体。结果表明 ,加入稀土铈的铁氧体纳米粉体性能优于其他几种材料 相似文献
128.
129.
A. R. Usha Devi R. Prabhu M. S. Uma 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):133-138
Production and analysis of non-Gaussian radiation fields has evinced a lot of attention recently.
Simplest way of generating such non-Gaussians is through adding (subtracting) photons to
Gaussian fields.
Interestingly, when photons are added to classical Gaussian fields, the resulting states exhibit
non-classicality.
Two important classical Gaussian radiation fields are coherent and thermal states. Here, we
study the non-classical features of
such states when photons are added to them. Non-classicality of these states shows up in the
negativity of the
Wigner function. We also work out the entanglement potential, a recently proposed measure
of non-classicality for these states. Our analysis reveals that photon added coherent states are
non-classical for all seed beam intensities; their non-classicality increases with the addition
of more number of photons. Thermal state exhibits non-classicality at all temperatures, when a
photon is added; lower the temperature, higher is their non-classicality. 相似文献
130.
《Electroanalysis》2005,17(9):794-799
The effectiveness of high frequency electromagnetic field influence on the analytical signal value in the stripping voltammetry method depending on such factors as the nature and concentration of the defined element, nature and concentration of the supporting electrolyte and agitation velocity has been studied. It has been demonstrated that an analytical signal increase may be achieved that allows one to lower a detection limit and to reduce the time of individual definition. The highest peak current is observed at some definite frequencies of the exterior field depending on the nature of the element and on the supporting electrolyte as well. 相似文献