全文获取类型
收费全文 | 3937篇 |
免费 | 77篇 |
国内免费 | 21篇 |
专业分类
化学 | 2731篇 |
晶体学 | 42篇 |
力学 | 48篇 |
数学 | 181篇 |
物理学 | 1033篇 |
出版年
2022年 | 16篇 |
2021年 | 33篇 |
2020年 | 44篇 |
2019年 | 54篇 |
2018年 | 38篇 |
2017年 | 21篇 |
2016年 | 54篇 |
2015年 | 68篇 |
2014年 | 64篇 |
2013年 | 162篇 |
2012年 | 169篇 |
2011年 | 222篇 |
2010年 | 103篇 |
2009年 | 139篇 |
2008年 | 205篇 |
2007年 | 212篇 |
2006年 | 216篇 |
2005年 | 178篇 |
2004年 | 169篇 |
2003年 | 155篇 |
2002年 | 168篇 |
2001年 | 131篇 |
2000年 | 106篇 |
1999年 | 69篇 |
1998年 | 51篇 |
1997年 | 56篇 |
1996年 | 52篇 |
1995年 | 41篇 |
1994年 | 53篇 |
1993年 | 62篇 |
1992年 | 74篇 |
1991年 | 58篇 |
1990年 | 50篇 |
1989年 | 57篇 |
1988年 | 43篇 |
1987年 | 56篇 |
1986年 | 47篇 |
1985年 | 55篇 |
1984年 | 51篇 |
1983年 | 39篇 |
1982年 | 27篇 |
1981年 | 41篇 |
1980年 | 30篇 |
1979年 | 48篇 |
1978年 | 40篇 |
1977年 | 25篇 |
1976年 | 31篇 |
1975年 | 24篇 |
1974年 | 28篇 |
1973年 | 21篇 |
排序方式: 共有4035条查询结果,搜索用时 15 毫秒
41.
Raman scattering spectra on a layer type compound 3RNbS2 were measured at 300 and 77 K, and three peaks were observed at 382, 325 and 281 cm?1 at 300 K. The vibration modes were analyzed in terms of Bromley's nearest neighbour model, and a good agreement with the experiment was obtained. 相似文献
42.
The field evaporation mass spectra of LaB6 are obtained with time-of-flight atom-probe field ion microscope in vacuum and in the presence of hydrogen, nitrogen and oxygen. The spectra are consistent with a preferential chemisorption of these gases on boron sites. 相似文献
43.
方永得 张玉虎 M.Oshima Y.Toh 周小红 M.Koizumi A.Osa A.Kimura Y.Hatsukawa T.Morikawa M.Nakamura M.Sugawara H.Kusakari 《中国物理 C》2006,30(2):99-104
利用在束γ谱学实验技术, 通过173Yb(19F,4nγ)反应
布居了188Au的高自旋态, 并对其准粒子带结构进行了研究. 基于实验测量结果, 对原有的双奇核188Au能级纲图做了较大的修改. 通过系统性比较, 对15+以上的能级结构进行了讨论. 相似文献
44.
Yoshimasa Nakamura 《Annali di Matematica Pura ed Applicata》1981,129(1):153-160
Summary
For the stationary axially symmetric vacuum, field, the Einstein equations reduce to a system for the logarithmic derivatives of the unknown function. An inverse scattering formula and a Bäcklund transformation are presented for the reduced system. As the simplest case, successive uses of the Bäcklund transformation give the Kasner type solutions and their generalization starting from the Minkowski metric. 相似文献
45.
The surface electromigration (SE) of ultrathin In films on Si(111)4 × 1-In surfaces has been investigated using experimental techniques based on μ-electron beams. On the basis of the finding that the SE velocity enhances as the strength of the electrostatic field (EF) fed through the substrate enhances, it is strongly suggested that the driving force of SE is an EF rather than a DC current fed through the substrate. It is found that a patch of ultrathin In film changes to an In patch of 1 × 1 periodicity during SE which is accompanied by spotty parts (named fine-polygons) at both the cathode and anode sides of the In patch. It is found that the fine-polygons are created at the cathode side and are stationary but grow in size to be eventually incorporated into the In-patch. A few In-islands are found on the cathode side of the In-patch and they show no translation but cycles of appearance, growth, decay, and disappearance during SE, by which mass-transportation is achieved. A plausible microscopic model for the SE is presented based on these findings. 相似文献
46.
M. Koizumi T. T. Inamura K. Morita M. Takami M. Wakasugi A. Yoshida M. Azuma H. Katsuragawa T. Horiguchi T. Ishizuka I. Nakamura M. Nakaoka A. Iivonen K. Valli S. Matsuki T. Murayama K. Shimomura T. Shinozuka I. Sugai Y. Tagishi 《Hyperfine Interactions》1992,74(1-4):181-191
We have constructed a fast atomic-beam collinear laser spectroscopy system connected to the on-line isotope separator facility
GARIS/IGISOL at RIKEN. This system is potentially powerful in studying refractory elements. To test the system, an off-line
collinear experiment was made on stable Hf isotopes produced by means of laser ablation technique. For production of radioactive
Hf isotopes, the use of the inverse kinematics of a fusion reaction,9Be(166Er,xn)175-x
Hf, was investigated. The radioactive isotope169Hf was successfully extracted from GARIS/IGISOL and accelerated up to 30 keV. 相似文献
47.
The modified wave and scattering operators are shown to be bounded between weighted L
2-spaces for two-body Schrödinger operators with long range potentials. 相似文献
48.
C. Kimura B. Beckford T. Fujibayashi T. Fujii Y. Fujii K. Futatsukawa T. Gogami O. Hashimoto Y. C. Han K. Hirose R. Honda K. Hosomi A. Iguchi T. Ishikawa H. Kanda Y. Kaneko M. Kaneta Y. Kasai T. Kawasaki S. Kiyokawa T. Koike K. Maeda N. Matsubara K. Miwa Y. Miyagi S. Nagao S. N. Nakamura A. Okuyama H. Shimizu T. Tamae H. Tamura N. Terada K. Tsukada F. Yamamoto T. O. Yamamoto H. Yamazaki 《Few-Body Systems》2013,54(7-10):1319-1322
Double charged pion photoproductions from the deuteron have been studied at Research Center for Electron Photon Science (ELPH), Tohoku University. Tagged photon beams in an energy range of 0.67 ≤ E γ ≤ 1.08 GeV were impinged on the liquid deuteron target. Produced charged particles were observed with the Neutral Kaon Spectrometer2 (NKS2). The γ d → π + π ? d process was clearly separated among the three charged tracks. We obtained the photon energy dependence of the normalized yields of this process. 相似文献
49.
Kawamura N Nagamine K Matsuzaki T Ishida K Nakamura SN Matsuda Y Tanase M Kato M Sugai H Kudo K Takeda N Eaton GH 《Physical review letters》2003,90(4):043401
A systematic experimental study on muon-catalyzed fusion was conducted using a series of solid deuterium and tritium mixtures. A variety of conditions were investigated, i.e., tritium concentrations from 20% to 70%, and temperatures from 5 to 16 K. With decreasing temperature, we observed an unexpected decrease in the muon cycling rate (lambda(c)) and an increase in the muon loss probability (W). The origins of these observed changes were interpreted by the temperature-dependence in the dt mu formation process for lambda(c) and that in the muon reactivation process after muon-to-alpha sticking for W. 相似文献
50.
A. Noda S. Nakamura Y. Iwashita S. Sakabe M. Hashida T. Shirai S. Shimizu H. Tongu H. Ito H. Souda A. Yamazaki M. Tanabe H. Daido M. Mori M. Kado A. Sagisaka K. Ogura M. Nishiuchi S. Orimo Y. Hayashi A. Yogo S. Bulanov T. Esirkepov A. Nagashima T. Kimura T. Tajima T. Takeuchi K. Matsukado A. Fukumi Z. Li 《Laser Physics》2006,16(4):647-653
In order to widely spread out particle beams utilized in cancer therapy, laser-produced ions are developed as the injection beam for an ion synchrotron dedicated for cancer therapy. Such a laser ion source is expected to contribute largely to the realization of compactness of the size and low cost of the cancer therapy accelerator. The energy spectrum of the laser-produced ions, however, has no peak, but their intensities decrease exponentially according to the increase of the energy. For the purpose of modifying such a situation, we have proposed a scheme to rotate the beam in the longitudinal phase space with the use of the RF electric field, which is phase-adjusted with the pulse laser. We aim for a reduction of the energy spread of ± 5% selected by an energy analyzer and slits to ±1% by such phase rotation. For this purpose, a quarter wavelength resonator with two gaps with the same resonant frequency as the source laser has already been fabricated, together with its RF power source. The above phase rotation system and its recent experimental realization are presented. 相似文献