全文获取类型
收费全文 | 102篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
化学 | 86篇 |
晶体学 | 2篇 |
数学 | 4篇 |
物理学 | 16篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1972年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有108条查询结果,搜索用时 15 毫秒
41.
M. Petkovi?S. Stojadinovi? R. Vasili?I. Bel?a Z. Nedi?B. Kasalica U.B. Mio? 《Applied Surface Science》2011,257(22):9555-9561
The growth of silicate tungsten bronzes on aluminum by plasma electrolytic oxidation in 12-tungstosilicic acid is experimentally investigated and discussed. Real time imaging and optical emission spectroscopy characterization of plasma electrolytic oxidation show that spatial density of microdischarges is the highest in the early stage of the process, while the percentage of oxide coating area covered by active discharge sites decreases slowly with time. Emission spectrum of microdischarges has several intensive band peaks originating either from aluminum electrode or from the electrolyte. Surface roughness of obtained oxide coatings increases with prolonged time of plasma electrolytic oxidation, as their microhardness decreases. Raman spectroscopy and energy dispersive X-ray spectroscopy are employed to confirm that the outer layer of oxide coatings formed during the plasma electrolytic oxidation process is silicate tungsten bronzes. 相似文献
42.
Mio Koyama Akito Shimomura Katsuhiko Miyamoto Takashige Omatsu 《Applied physics. B, Lasers and optics》2014,116(2):249-254
The frequency-doubling of a picosecond vortex fiber laser, formed of a 1-μm picosecond master laser and a large-mode-area fiber amplifier by using a nonlinear LiB3O5, crystal, was performed. A maximum second-harmonic power of 7.7 W was achieved, corresponding to a conversion efficiency of 31 %. The second harmonic had an annular spatial form owing to a phase singularity with a doubled topological charge, and its wavefront helicity was selectively controlled by tuning the stress applied to the fiber amplifier. 相似文献
43.
Amplitude modulation of laser light is required for resonant sideband extraction employed in gravitational-wave detectors. Amplitude modulation with electro-optic phase modulators is realized by interferometric phase-to-amplitude conversion. Although two outputs modulated at opposite phases to each other are obtained, usually only one of them is utilized and the other is abandoned. The reuse of this abandoned light improves the power efficiency of the modulation. This can be realized by inverting the modulation phase of one output with a delay line and adding it to the other coherently. Moreover, this system selects a high-efficiency operating point and modulates the light in a linear range. We demonstrate that the modulation system can be operated with a power loss that is due only to the losses of the optical components. 相似文献
44.
Mio Matsumura Yuki Matsuhashi Masato Kawakubo Tadashi Hyodo Yuki Murata Masatoshi Kawahata Kentaro Yamaguchi Shuji Yasuike 《Molecules (Basel, Switzerland)》2021,26(1)
The expectation that antimony (Sb) compounds should display phosphorescence emissions based on the “heavy element effect” prompted our interest in the introduction of antimony to a biaryl as the bridging atom in a fused heterole system. Herein, the synthesis, molecular structures, and optical properties of novel benzene-fused heteroacenes containing antimony or arsenic atoms are described. The stiboles and arsole were prepared by the condensation of dibromo(phenyl)stibane or dichloro(phenyl)arsine with dilithium intermediates derived from the corresponding dibromo compounds. Nuclear magnetic resonance (NMR) spectroscopy and X-ray crystal analysis revealed that the linear pentacyclic stibole was highly symmetric in both the solution and crystal states. In contrast, the curved pentacyclic stibole adopted a helical structure in solution, and surprisingly, only M helical molecules were crystallized from the racemate. All synthesized compounds produced very weak or no emissions at room temperature or in the solid state. In contrast, the linear penta- and tetracyclic stiboles exhibited clear phosphorescence emissions in the CHCl3 frozen matrix at 77 K under aerobic conditions. 相似文献
45.
Dr. Masaki Yoshida Dr. Mio Kondo Sena Torii Prof. Ken Sakai Prof. Shigeyuki Masaoka 《Angewandte Chemie (International ed. in English)》2015,54(27):7981-7984
Rational molecular design of catalytic systems capable of smooth O? O bond formation is critical to the development of efficient catalysts for water oxidation. A new ruthenium complex was developed, which bears pendant SO3? groups in the secondary coordination sphere: [Ru(terpy)(bpyms)(OH2)] (terpy=2,2′:6′,2′′‐terpyridine, bpyms=2,2′‐bipyridine‐5,5′‐bis(methanesulfonate)). Water oxidation driven by a Ce4+ oxidant is distinctly accelerated upon introduction of the pendant SO3? groups in comparisons to the parent catalyst, [Ru(terpy)(bpy)(OH2)]2+ (bpy=2,2′‐bipyridine). Spectroscopic, electrochemical, and crystallographic investigations concluded that the pendant SO3? groups promote the formation of an O? O bond via the secondary coordination sphere on the catalyst, whereas the influence of the pendant SO3? groups on the electronic structure of the [Ru(terpy)(bpy)(OH2)]2+ core is negligible. The results of this work indicate that modification of the secondary coordination sphere is a valuable strategy for the design of water oxidation catalysts. 相似文献
46.
Iwao Okamoto Yusuke Takahashi Mika Sawamura Mio Matsumura Hyuma Masu Kosuke Katagiri Isao Azumaya Masanori Nishino Yukari Kohama Nobuyoshi Morita Osamu Tamura Hiroyuki Kagechika Aya Tanatani 《Tetrahedron》2012,68(27-28):5346-5355
Redox-induced conformational alteration of N-aryl-N-phenylamides, in which the N-aryl group consists of a hydroquinone–p-quinone system, was examined. The reduced form bearing a dihydroxyphenyl or dimethoxyphenyl group exists mainly in the E-form, whereas the oxidized form bearing a N-benzoquinone moiety takes the Z-form both in the crystal and in solution. This redox-induced conformational alteration is associated with a marked change in optical properties. This system appears to have suitable properties for use in external redox stimulus-responsive functional switching. 相似文献
47.
The crystallization dynamic of amorphous GeTe 50 nm thick films deposited on a SiO2/Si substrate by RF magnetron sputtering, either ion implanted by Ge+ ions or not, has been analyzed in situ by optical microscopy during annealing in the 143-155 °C temperature range. Raman spectroscopy has been also performed in as deposited, ion implanted (i.i.) and melt quenched (m.q.) amorphous samples to compare the local order among the different amorphous structure. Nucleation and growth rates, for i.i. and as deposited samples, have been observed and directly compared by optical microscopy in a region of about 5 × 104 μm2. From these data, the activation energy and pre-exponential terms of each process have been calculated. The nucleation rate and growth velocity of the i.i. films increased by a factor thirteen and a factor three with respect to the as deposited samples. This evidence, in agreement with Raman spectroscopy data, suggests that implantation, providing kinetic energy by collision cascade, induces a local atomic rearrangement towards more relaxed amorphous states. As a result the crystallization kinetic is enhanced by the reduction of wrong bonds formed during sputter deposition, a process which occurs far from equilibrium conditions. 相似文献
48.
49.
Hoover S Nam J Gorham PW Grashorn E Allison P Barwick SW Beatty JJ Belov K Besson DZ Binns WR Chen C Chen P Clem JM Connolly A Dowkontt PF DuVernois MA Field RC Goldstein D Vieregg AG Hast C Israel MH Javaid A Kowalski J Learned JG Liewer KM Link JT Lusczek E Matsuno S Mercurio BC Miki C Miočinović P Naudet CJ Ng J Nichol RJ Palladino K Reil K Romero-Wolf A Rosen M Ruckman L Saltzberg D Seckel D Varner GS Walz D Wu F 《Physical review letters》2010,105(15):151101
We report the observation of 16 cosmic ray events with a mean energy of 1.5 × 101? eV via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen events are seen to have a phase inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. Based on a likelihood analysis, we estimate angular pointing precision of order 2° for the event arrival directions. 相似文献
50.