全文获取类型
收费全文 | 760篇 |
免费 | 34篇 |
国内免费 | 3篇 |
专业分类
化学 | 586篇 |
晶体学 | 8篇 |
力学 | 5篇 |
数学 | 10篇 |
物理学 | 188篇 |
出版年
2023年 | 10篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 10篇 |
2019年 | 24篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 16篇 |
2014年 | 27篇 |
2013年 | 46篇 |
2012年 | 36篇 |
2011年 | 37篇 |
2010年 | 34篇 |
2009年 | 30篇 |
2008年 | 48篇 |
2007年 | 45篇 |
2006年 | 59篇 |
2005年 | 43篇 |
2004年 | 39篇 |
2003年 | 30篇 |
2002年 | 34篇 |
2001年 | 28篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有797条查询结果,搜索用时 15 毫秒
761.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Jamel A Alexander J Aoki K Aphecetche L Armendariz R Aronson SH Averbeck R Awes TC Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bjorndal MT Boissevain JG Borel H Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choudhury RK Chujo T Cianciolo V Cobigo Y 《Physical review letters》2005,94(8):082302
We report on charged hadron production in deuteron-gold reactions at sqrt[s(NN)]=200 GeV. Our measurements in the deuteron direction cover 1.4相似文献
762.
We report a scheme for generating pulsed polarization-entangled photon pairs based on conversion from time-bin entanglement to polarization entanglement by use of an orthogonal polarization delay circuit and post-selection. We have experimentally demonstrated the scheme, using a periodically poled lithium niobate waveguide, and successfully obtained polarization entanglement in the 1.55-microm telecom wavelength band. 相似文献
763.
Quantitative image reconstruction of GaN quantum dots from oversampled diffraction intensities alone
Miao J Nishino Y Kohmura Y Johnson B Song C Risbud SH Ishikawa T 《Physical review letters》2005,95(8):085503
The missing data problem, i.e., the intensities at the center of diffraction patterns cannot be experimentally measured, is currently a major limitation for wider applications of coherent diffraction microscopy. We report here that, when the missing data are confined within the centrospeckle, the missing data problem can be reliably solved. With an improved instrument, we recorded 27 oversampled diffraction patterns at various orientations from a GaN quantum dot nanoparticle and performed quantitative image reconstruction from the diffraction intensities alone. This work in principle clears the way for single-shot imaging experiments using x-ray free electron lasers. 相似文献
764.
Adcox K Adler SS Ajitanand NN Akiba Y Alexander J Aphecetche L Arai Y Aronson SH Averbeck R Awes TC Barish KN Barnes PD Barrette J Bassalleck B Bathe S Baublis V Bazilevsky A Belikov S Bellaiche FG Belyaev ST Bennett MJ Berdnikov Y Botelho S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy J Butsyk S Carey TA Chand P Chang J Chang WC Chavez LL Chernichenko S Chi CY Chiba J Chiu M Choudhury RK Christ T Chujo T Chung MS Chung P Cianciolo V Cole BA D'Enterria DG 《Physical review letters》2001,87(5):052301
765.
We propose a novel technique for wideband tunable wavelength conversion of return-to-zero signals by optical time gating of a supercontinuum (SC) light source. A SC pulse generated by nonlinear propagation in a normal-dispersion fiber has a rectangular shape with highly linear upchirping. By control of the optical time-gating position, the center wavelength of time-gated SC pulse can be precisely tuned. Error-free 10-Gbit/s wavelength conversion with a tuning range of 27.1 nm is experimentally demonstrated. 相似文献
766.
767.
Yoshiki Chujo Hisaaki Kobayashi Yuya Yamashita 《Journal of polymer science. Part A, Polymer chemistry》1989,27(6):2007-2014
Hydroxyl- or amino-terminated prepolymers were prepared by radical polymerization of methyl methacrylate in the presence of 2-mercaptoethanol or 2-aminoethanethiol hydrochloride, respectively, as a chain transfer agent. The resulting prepolymers were subjected to react with trimellitic anhydride to form aromatic dicarboxyl-terminated poly(methyl methacrylate)s. These condensation-type macromonomers and terephthalic acid were condensed with bisphenol-A to produce polyester–poly(methyl methacrylate) graft copolymers. 相似文献
768.
769.
In this letter, we estimate the refractive index distribution in a photo-induced waveguide. The photo-induced waveguide was fabricated by scanning a focused laser beam through a lithium niobate crystal. We made use of a parametric model of refractive index distribution of the photo-induced waveguide. The results of numerical simulation on the near-field patterns of curved waveguides are compared with experimental results. 相似文献
770.
The Mössbauer spectra of β- and α-Si3N4 containing Fe have been measured at 300 and 93 K. The former consists of a singlet and a doublet, whereas the latter exhibits paramagnetic hyperfine patterns and a doublet. The single line and hyperfine patterns arise from isolated high-spin Fe3+ ions which are bonded equivalently with 4 nitrogen neighbors. Both doublets arise from high-spin Fe3+ ion-pairs each of which is strongly bonded by a kind of superexchange force. In β-Si3N4 the Fe3+ ions occupy the same sites regardless of whether they are doped into the crystal lattice before or after its preparation, while in α-Si3N4 the Fe3+ ions are located at different sites depending on the doping procedure. From the Raman spectra, the difference in the Mössbauer spectra for the two compounds is attributable to different relaxation by lattice phonons of the host crystals.The Mössbauer spectral lines for β-Si3N4 alone have been found to decrease in intensity with tune even at room temperature, such an ageing being observed to be entirely suppressed by γ-irradiation. From different behaviors of the three lines in the ageing and quenching from 1150°C down to room temperature, the ageing is interpretable based on a model that the Fe3+ ions jump from substitutional sites into interestitial sites and take place thermal vibration with a large amplitude there. 相似文献