全文获取类型
收费全文 | 549篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
化学 | 317篇 |
晶体学 | 5篇 |
力学 | 10篇 |
数学 | 46篇 |
物理学 | 190篇 |
出版年
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 16篇 |
2014年 | 12篇 |
2013年 | 26篇 |
2012年 | 28篇 |
2011年 | 30篇 |
2010年 | 17篇 |
2009年 | 28篇 |
2008年 | 43篇 |
2007年 | 31篇 |
2006年 | 31篇 |
2005年 | 36篇 |
2004年 | 23篇 |
2003年 | 23篇 |
2002年 | 23篇 |
2001年 | 15篇 |
2000年 | 18篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有568条查询结果,搜索用时 15 毫秒
81.
K. Tanaka K. Yoshizawa T. Koike T. Yamabe J. Yamauchi Y. Deguchi S. Yata 《Solid State Communications》1984,52(3):343-345
ESR measurements have been performed on the polyacenic material prepared by the pyrolytic treatment of phenol-formaldehyde resin. Six kinds of samples (A)-(F) with various electrical conductivity (σ) were employed for the measurements. Each sample shows a single narrow line, the g-values of which suggest the existence of unpaired electrons of π-type. If the sample (F) (σ = 1 × 10° S cm?1) the single narrow line becomes drastically diminished in the presence of a small amount of oxygen. 相似文献
82.
The 13C NMR spectra of β-carboline alkaloids were determined, and unambiguous assignments of the spectra were carried out from the long-range coupling constants. 相似文献
83.
The detection limit for tris(1,1,1-trifluoro-4-(2-thienyl)-2,4-butanediono)-europium(III) is established as 2 pg l-1. A highly sensitive fluorimetric system consisting of a nitrogen laser and a pulse-gated photon counter is used. 相似文献
84.
Matsuo Maeda Sadao Hibi Fumihiro Itoh Shunji Nomura Tatsuro Kawaguchi Hiromichi Kawai 《Journal of Polymer Science.Polymer Physics》1970,8(8):1303-1322
A mathematical representation of the transformation of an orientation function between two sets of Cartesian coordinates is discussed in terms of a series expansion of the distribution function in generalized spherical harmonics. A general procedure for calculating the mechanical anisotropy of a single-phase system (a polycrystalline material) from the orientation of its structural units and the intrinsic mechanical anisotropy of the structural unit is discussed in relation to the transformation of the orientation distribution function, i.e., mutual conversion of the coefficients in the expansion of the distribution function between the two sets of Cartesian coordinates. The procedure is extended to a two-phase systems (semicrystalline polymers) containing structural units composed of crystalline and noncrystalline materials in three different geometrical arrangements. 相似文献
85.
86.
Optical near-field plasmon-enhancement techniques have made marked contributions to the field of subwavelength optical beam
spot generation for photonic devices. However, the metal material used is not sufficiently heat resistant for high-temperature
operating requirements, such as laser-assisted magnetic recording storage. Therefore, it is preferable to use a dielectric
material as a heat source for this application. To realize a subwavelength optical beam spot size using a dielectric material,
we extensively analyze a leaky mode dielectric waveguide with a thin core. Finally, we show a new ridge-type dielectric waveguide
using a leaky mode operation for a subwavelength beam spot. 相似文献
87.
During the past decade, the Ratip program has been found useful for calculating a variety of atomic properties, including energies, transition probabilities, Auger parameters as well as a number of excitation, ionization and capture cross sections for processes with a single electron in the continuum. Recently, in addition, this suite of programs was extended to predict also the isotope shift and hyperfine parameters of open-shell atoms and ions. Here, we review the latest developments of the Ratip program with emphasis on the specific mass-shift M sms and field-shift F parameters. Detailed computations for these parameters have been carried out especially for the $4s\;^2S_{1/2} - 4p\;^2P_{1/2,3/2}$ transitions at ~ 397 nm of singly-charged Ca?+? ions and are compared with available data from the literature. 相似文献
88.
89.
90.
In this paper, we investigate the Gauss maps of a Ricci-mean curvature flow. A Ricci-mean curvature flow is a coupled equation of a mean curvature flow and a Ricci flow on the ambient manifold. Ruh and Vilms (Trans Am Math Soc 149: 569–573, 1970) proved that the Gauss map of a minimal submanifold in a Euclidean space is a harmonic map, and Wang (Math Res Lett 10(2–3):287–299, 2003) extended this result to a mean curvature flow in a Euclidean space by proving its Gauss maps satisfy the harmonic map heat flow equation. In this paper, we deduce the evolution equation for the Gauss maps of a Ricci-mean curvature flow, and as a direct corollary we prove that the Gauss maps of a Ricci-mean curvature flow satisfy the vertically harmonic map heat flow equation when the codimension of submanifolds is 1. 相似文献