全文获取类型
收费全文 | 368篇 |
免费 | 6篇 |
国内免费 | 3篇 |
专业分类
化学 | 233篇 |
晶体学 | 4篇 |
力学 | 8篇 |
数学 | 19篇 |
物理学 | 113篇 |
出版年
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 14篇 |
2011年 | 22篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 13篇 |
2007年 | 24篇 |
2006年 | 15篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 8篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有377条查询结果,搜索用时 31 毫秒
71.
Akira Ishida Yuichi Sasaki Ginga Akimoto Taikan Suehara Toshio Namba Shoji Asai Tomio Kobayashi Haruo Saito Mitsuhiro Yoshida Kenichi Tanaka Akira Yamamoto 《Hyperfine Interactions》2012,212(1-3):133-140
Positronium is an ideal system for the research of the quantum electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of positronium, ΔHFS, gives a good test of the bound state calculations and probes new physics beyond the Standard Model. A new method of QED calculations has revealed the discrepancy by 15 ppm (3.9σ) of ΔHFS between the QED prediction and the experimental average. There would be possibility of new physics or common systematic uncertainties in the previous all experiments. We describe a new experiment to reduce possible systematic uncertainties and will provide an independent check of the discrepancy. We are now taking data and the current result of ΔHFS?=?203.395 1 ±0.002 4 (stat., 12 ppm) ±0.001 9 (sys., 9.5 ppm) GHz has been obtained so far. A measurement with a precision of O(ppm) is expected within a year. 相似文献
72.
Tanemi Asai Shu Shimamoto Tohru Shibata Tadatomo Kawai Shinya Teramachi 《Macromolecular Symposia》2006,242(1):5-12
The chromatographic method for the determination of the intermolecular acetyl distribution of cellulose triacetate (CTA) was established; the key point of the method is a gradient elution by gradually changing the solvent composition of the ternary mixture of chloroform, methanol, and water on a phenyl-bonded silica gel stationary phase. A positive correlation between the retention time and the degree of acetyl substitution was observed under the established chromatographic conditions. The validity of the elution peak width as the measure of intermolecular acetyl distribution was confirmed by the co-injection and fractionation experiments and the comparison of a peak width with a statistically estimated distribution. 相似文献
73.
74.
J. S. Zheng Y. Kobayashi J. Nakamura K. Asai G. L. Zhang F. Ambe 《Hyperfine Interactions》1992,68(1-4):307-310
151Eu Mössbauer spectroscopy on Eu VO3 in the temperature range of 9-293 K indicated that there is a large increase ofeV zzQg when temperature goes from 293K down to 9K. 相似文献
75.
M. Asai J. L. Bailly S. Banerjee F. Bruyant W. M. Bugg C. Caso H. Dibon R. Di Marco T. Emura B. Epp A. Ferrando Y. Fisyak F. Fontanelli P. Girtler A. Gurtu R. Hamatsu E. L. Hart P. Herquet J. Hrubec Y. Iga N. Khalatjan E. Kistenev P. Ladron de Guevara J. MacNaughton J. C. Marin M. Markytan I. S. Mittra L. Montanet G. Neuhofer N. Ohshima Y. Petrovikh P. Porth B. Pijlgroms M. Regler T. Rodrigo J. Saliclo J. B. Singh S. Squarcia P. Stamer V. Stopchenko U. Trevisan C. Willmott G. Zholobov EHS-RCBC Collaboration 《Zeitschrift fur Physik C Particles and Fields》1985,27(1):11-19
76.
M. Ishii Y. Kuwano S. Asaba T. Asai M. Kawamura N. Senguttuvan T. Hayashi M. Koboyashi M. Nikl S. Hosoya K. Sakai T. Adachi T. Oku H. M. Shimizu 《Radiation measurements》2004,38(4-6):571-574
Lithium tetraborate single crystal doped with Cu seems to be a promising new material for neutron detection. With the presence of Li and B, both having large cross section for neutron capture, efficient neutron detection is expected with high-energy deposits. In the present work, we chose 14 different dopants from Ia, Ib, IIIa, IVa and Va groups in the periodic table besides the rare earth Ce ion. The crystals were grown to a size of 20 mm in diameter and 70 mm in length by vertical Bridgman method. The grown crystals were characterized by optical transmittance and excitation–emission studies. Transmittance and emission characteristics of Ce-doped lithium borate glass are also reported. 相似文献
77.
Takahide Oya Yoshiyuki Takahashi Masayuki Ikebe Tetsuya Asai Yoshihito Amemiya 《Superlattices and Microstructures》2003,34(3-6):253
A single-electron circuit can be operated as a discrete dynamical system because it changes its internal state discontinuously because of electron tunneling. To confirm this idea, we designed a sample circuit for discrete dynamical operation and confirmed by computer simulation that the circuit successfully generated a sequence of discrete-time outputs by following a return map. The concept of discrete dynamical systems will be useful in developing new functional systems that consist of quantum devices and nanostructures. 相似文献
78.
Diffusion of a Li atom in an anode material β-LiAl was studied over the composition range of 48.0–50.2 at % Li by the 7Li magnetic relaxation times. Dependence of T1 upon temperature and the resonance frequency was successfully explained by a vacancy diffusion on the Li sublattice involving a distribution of the activation energy for migration, Ea. The central value of Ea was almost independent of the composition (? 13.8 kJ mol-1), while the width of distribution increased with increase of the number of substituted Li on the Al sublattice. The obtained diffusion constants, extrapolated to 415°C, were larger by a factor of 1.8–3.4 than those obtained by the electrochemical method. 相似文献
79.
R. Akers G. Alexander J. Allison N. Altekamp K. Ametewee K. J. Anderson S. Anderson S. Arcelli S. Asai D. Axen et al. 《Zeitschrift fur Physik C Particles and Fields》1995,67(3):365-378
The forward-backward asymmetry of
has been measured using approximately 2.15 million hadronicZ
0 decays collected at the LEP e+e– collider with the OPAL detector. A lifetime tag technique was used to select an enriched
event sample. The measurement of the
asymmetry was then performed using a jet charge algorithm to determine the direction of the primary quark. Values of:
相似文献
80.
A new catalytic system for beta-alkylation of secondary alcohols has been developed. In the presence of [CpIrCl(2)](2) (Cp = pentamethylcyclopentadienyl) catalyst and base, the reactions of various secondary alcohols with primary alcohols give beta-alkylated higher alcohols in good to excellent yields without any hydrogen acceptor or hydrogen donor. This reaction proceeds via successive hydrogen-transfer reactions and aldol condensation. [reaction: see text] 相似文献
|