全文获取类型
收费全文 | 5078篇 |
免费 | 177篇 |
国内免费 | 24篇 |
专业分类
化学 | 3270篇 |
晶体学 | 63篇 |
力学 | 129篇 |
数学 | 606篇 |
物理学 | 1211篇 |
出版年
2023年 | 19篇 |
2022年 | 69篇 |
2021年 | 89篇 |
2020年 | 90篇 |
2019年 | 101篇 |
2018年 | 141篇 |
2017年 | 120篇 |
2016年 | 234篇 |
2015年 | 131篇 |
2014年 | 192篇 |
2013年 | 334篇 |
2012年 | 352篇 |
2011年 | 429篇 |
2010年 | 264篇 |
2009年 | 261篇 |
2008年 | 346篇 |
2007年 | 332篇 |
2006年 | 259篇 |
2005年 | 193篇 |
2004年 | 184篇 |
2003年 | 151篇 |
2002年 | 155篇 |
2001年 | 80篇 |
2000年 | 104篇 |
1999年 | 56篇 |
1998年 | 36篇 |
1997年 | 37篇 |
1996年 | 28篇 |
1995年 | 29篇 |
1994年 | 28篇 |
1993年 | 26篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 26篇 |
1989年 | 31篇 |
1988年 | 18篇 |
1987年 | 15篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 15篇 |
1981年 | 26篇 |
1980年 | 17篇 |
1979年 | 16篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1975年 | 19篇 |
1974年 | 13篇 |
排序方式: 共有5279条查询结果,搜索用时 15 毫秒
111.
Vossen A Seidl R Adachi I Aihara H Aushev T Balagura V Bartel W Bischofberger M Bondar A Bračko M Browder TE Chang MC Chen A Chen P Cheon BG Cho K Choi Y Eidelman S Feindt M Gaur V Gabyshev N Garmash A Golob B Perdekamp MG Haba J Hayasaka K Horii Y Hoshi Y Hou WS Hyun HJ Inami K Ishikawa A Iwabuchi M Iwasaki Y Iwashita T Joshi NJ Kichimi H Kim HO Kim MJ Ko BR Kumita T Lange JS Lee MJ Lee SH Leitgab M Li Y Liu C Liventsev D Louvot R McOnie S Miyata H Miyazaki Y Mizuk R Mohanty GB Nakano E 《Physical review letters》2011,107(7):072004
The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e(+)e(-) annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π(+)π(-) pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672 fb(-1) data sample that contains 711 × 10(6) π(+)π(-) pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. 相似文献
112.
N. I. Plyusnin V. M. Il’yashchenko S. A. Kitan’ N. A. Tarima 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(4):734-745
Auger-electron spectroscopy, electron-energy loss spectroscopy, low-energy electron diffraction, and atomic-force microscopy
are employed to investigate the growth mechanism, composition, structural and phase states, and morphology of Cu films (0.1–1
nm thick) deposited on a Si(001)-2 × 1 surface at a lower temperature of Cu evaporation (900°C) and room temperature of a
substrate. The Cu film phase is shown to start growing on the Si(001)−2 × 1 surface after three Cu monolayers (MLs) are condensed. It has been revealed that atoms of Cu and Si(001) are mixed, a
Cu2Si film phase is formed, and, thereafter, Cu3Si islands arise at a larger coating thickness. Annealing of the first Cu ML leads to reconstruction of the Si(001)-1 × 1-Cu
surface layer, thereby modifying the film growth mechanism. As a consequence, the Cu2Si film phase arises when the thickness reaches two to four MLs, and bulk Cu3Si silicide islands begin growing at five to ten MLs. When islands continue to grow, their height and density reach, respectively,
1.5 nm and 2 × 1011 cm−2 and the island area is 70% of the substrate surface at a thickness of ten MLs. 相似文献
113.
Tomasz ?ojewski Jacek Bagniuk Andrzej Ko?odziej Joanna ?ojewska 《Applied Physics A: Materials Science & Processing》2011,105(3):753-761
This study proposes a method to estimate the lipid content in binding media in paintings that can be used at any laboratory
equipped with an infrared spectrometer. The lipid content estimator, termed greasiness index (GI), is defined as a ratio of
lipid ν(C=O) and protein amide I bands at 1743 and 1635 cm−1, respectively. Three Fourier transform infrared (FTIR) sampling techniques were evaluated for GI determination: reflective
attenuated total reflection—ATR, specular reflection microscopy—μSR and photoacoustic—PAS. A set of model painting samples containing three tempera binding media (casein, egg, egg + oil),
seven pigments and one varnish type were used in the study. Multivariate analysis was used to evaluate the resulting data.
A good reproducibility of GI was obtained by ATR and PAS but not with μSR. The discriminative power of the technique is higher for unvarnished samples, but, generally, the GI estimator can be used
for the categorisation of binding media in large populations of painting samples analysed with the same FTIR technique (sampling
technique, detection, etc.). 相似文献
114.
Light scattering by small dielectric particles of an arbitrary axially symmetric shape is analyzed. A simple approximate expression
that governs the polarizability of the particle is found under the assumption of field homogeneity inside of these particles.
The expression includes four relatively simple one-dimensional integrals that can be calculated analytically for some types
of particles (except for spheroids). A comparison with the numerical data obtained for various Chebyshev particles and finite
cylinders showed that the obtained approximation yields acceptable results, even when the shape of scatterers is significantly
different from spheroidal. For spheroids, our approximation coincides with the Rayleigh one. 相似文献
115.
We have developed a new type of all-fiber band-rejection filter consisting of a helicoidal long-period fiber grating pair of opposite helicities, which provides highly flexible spectral control over the rejection bandwidth. The detailed fabrication method and operation principles of the proposed bandwidth-tunable band-rejection filter are described. The proposed device enables unique rejection bandwidth tuning over more than 14 nm at the rejection level of 15 dB, with low insertion loss and polarization-dependent loss achieved by adjusting torsion stress. 相似文献
116.
Al2O3 incorporated HfO2 films grown by atomic layer deposition (ALD) were investigated by high-resolution X-ray photoelectron spectroscopy (HRXPS). The core level energy state of a 15 Å thick film showed a shift to higher binding energy, as the result of a silicate formation and Al2O3 incorporation. The incorporation of Al2O3 into the HfO2 film had no effect on silicate formation at the interface between the film and Si, while the ionic bonding characteristics and hybridization effects were enhanced compared to a pure HfO2 film. The dissociation of the film in an ultrahigh vacuum (UHV) is effectively suppressed compared to a pure HfO2 film, indicating an enhanced thermal stability of Hf-Al-O. Any dissociated Al2O3 on the film surface was completely removed into the vacuum by vacuum annealing treatment over 850 °C, while HfO2 contributed to Hf silicide formation on the film surface. 相似文献
117.
118.
Eno S Auchincloss P Blanis D Bodek A Budd H Fry CA Harada H Ho YH Kim YK Kumita T Mori T Olsen SL Shaw NM Sill A Thorndike EH Ueno K Zheng HW Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Mao ZP Xu YT Zhu YC Abashian A Gotow K Hu KP Low EH Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Smith JR Stuart D Williams MC Abe K Fujii Y Higashi Y Kim SK 《Physical review letters》1989,63(18):1910-1913
119.
Shaw NM Blanis D Bodek A Budd H Coombes R Eno S Fry CA Harada H Ho YH Kim YK Kumita T Mori T Olsen SL Sill A Thorndike EH Ueno K Zheng HW Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Mao ZP Xu YT Zhu YC Abashian A Gotow K Hu K Low EH Mattson ME Naito F Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Smith JR Sparks K Williams MC Abe K Fujii Y Higashi Y Kim SK 《Physical review letters》1989,63(13):1342-1345
120.