全文获取类型
收费全文 | 3234篇 |
免费 | 978篇 |
国内免费 | 270篇 |
专业分类
化学 | 1061篇 |
晶体学 | 51篇 |
力学 | 159篇 |
综合类 | 26篇 |
数学 | 192篇 |
物理学 | 2993篇 |
出版年
2024年 | 8篇 |
2023年 | 39篇 |
2022年 | 95篇 |
2021年 | 97篇 |
2020年 | 102篇 |
2019年 | 78篇 |
2018年 | 81篇 |
2017年 | 134篇 |
2016年 | 145篇 |
2015年 | 155篇 |
2014年 | 234篇 |
2013年 | 266篇 |
2012年 | 209篇 |
2011年 | 242篇 |
2010年 | 191篇 |
2009年 | 216篇 |
2008年 | 263篇 |
2007年 | 218篇 |
2006年 | 242篇 |
2005年 | 184篇 |
2004年 | 170篇 |
2003年 | 154篇 |
2002年 | 132篇 |
2001年 | 105篇 |
2000年 | 110篇 |
1999年 | 94篇 |
1998年 | 91篇 |
1997年 | 69篇 |
1996年 | 60篇 |
1995年 | 42篇 |
1994年 | 34篇 |
1993年 | 38篇 |
1992年 | 39篇 |
1991年 | 23篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 9篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有4482条查询结果,搜索用时 15 毫秒
21.
22.
Sean D. Brooks M. F. Mahmood J. A. Donaldson 《Journal of Mathematical Modelling and Algorithms》2004,3(1):19-29
A numerical investigation, based on the split-step Fourier transform algorithm of all optical switching of solitons in a low
birefringent optical fiber is presented. The numerical algorithm is described in detail.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
23.
24.
25.
Takayuki Sakaguchi 《Optical Review》2003,10(3):136-139
We have succeeded in the operation of rotating a fine particle which was held without mechanical contact by circularly polarized laser beams with opposite propagation directions. A polystyrene latex particle 11.9 μm in diameter deformed in a disk-like shape was dispersed in water, and was trapped using the anti-parallel collinear laser beams which were set up so that they had the circular polarization rotating in the same direction. It was observed that the trapped particle rotated in the same direction as the rotation of the circular polarization of light. Inversion of the rotational direction of the circular polarization of light reversed the direction of the rotation of the particle. Although the rotational speed of a particle varied significantly from particle to particle, it was found to be proportional to the laser beam intensity. A typical value for the rotational speed per beam intensity was 2.1 Hz/W. 相似文献
26.
27.
In this note we make a correction in the paper [1] by two of the authors. Specifically we modify an auxiliary localization
result and prove that the applications to the saturation theory of some outstanding conservative operators remain valid. Moreover,
we enrich a corollary dealing with the well-known Szász-Mirakjan operators.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
28.
M. Ferro-Luzzi Z.-L. Zhou J.F.J. van den Brand H.J. Bulten J. Lang H.R. Poolman 《Hyperfine Interactions》1997,110(3-4):239-257
We present data showing hyperfine transitions in an atomic deuterium beam induced by the (476 MHz) radio-frequency field of
a 704 MeV electron beam in a storage ring. A polarized deuterium beam, produced in an atomic beam source, was crossed with
a stored electron beam and analyzed with a Breit--Rabi polarimeter. Electron-beam induced transitions were singled out by
injecting different combinations of hyperfine states. Transition probabilities as high as 70% were measured at large currents
(~ 100 mA). All possible deuterium transitions for a radio-frequency of 476 MHz were observed. In addition, a 1--6 transition
resulting from the first harmonic (952 MHz) was observed.
The effects of these transitions are of general importance for the polarized internal target technique applied in nuclear
and particle physics experiments. The data are reasonably described by numerical estimates. The observed mechanism can be
exploited to create nuclear polarized atoms when injecting electron polarized atoms with no net nuclear polarization into
a storage cell. However, when nuclear polarized atoms are injected, care should be taken to avoid this mechanism, since it
would result in depolarization of the atoms. The studies enabled us to choose the magnetic guide field during our spin-dependent
electron--deuteron scattering experiments, such that electron-beam induced depolarizing effects were avoided.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
29.
The effect of radiation gain saturation in quantum-well heretostructures was investigated in the system GaAs—AlGaAs with regard
to the spectral line broadening and the type of radiation polarization.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 6, pp. 797–800, November–December, 1997. 相似文献
30.
Applied Biochemistry and Biotechnology - 相似文献