全文获取类型
收费全文 | 215篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 152篇 |
晶体学 | 2篇 |
力学 | 22篇 |
数学 | 2篇 |
物理学 | 41篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 17篇 |
2007年 | 14篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1967年 | 3篇 |
排序方式: 共有219条查询结果,搜索用时 125 毫秒
81.
Kazuhiko Kitano Yuuki Inoue Ryosuke Matsuno Madoka Takai Kazuhiko Ishihara 《Colloids and surfaces. B, Biointerfaces》2009,74(1):350-357
For preparing a “highly lubricated biointerface”, which has both excellent lubricity and biocompatibility, we investigated the factors responsible for resistance to friction during polymer grafting. We prepared poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(methyl methacrylate) (PMMA) brush layers with high graft density and well-controlled thickness using atom transfer radical polymerization (ATRP). We measured the water absorptivity in the polymer brush layers and the viscoelasticity of the polymer-hydrated layers using a quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. The PMPC brush layer had the highest water absorptivity, while the PMPC-hydrated layer had the highest fluidity. The friction properties of the polymer brush layers were determined in air, water, and toluene by atomic force microscopy (AFM). The friction on each polymer brush decreased only when a good solvent was chosen for each polymer. In conclusion, the brush layer possessing high water absorptivity and fluidity in water contributes to reduce friction. PMPC grafting is an effective and promising method for obtaining highly lubricated biointerfaces. 相似文献
82.
Tashima T Kitano T Ozdemir SK Yamamoto T Koashi M Imoto N 《Physical review letters》2010,105(21):210503
We demonstrate an optical gate that increases the size of polarization-based W states by accessing only one of the qubits. Using this gate, we have generated three-photon and four-photon W states with fidelities 0.836 ± 0.042 and 0.784 ± 0.028, respectively. We also confirmed the existence of pairwise entanglement in every pair of qubits, including the one that was left untouched by the gate. The gate is applicable to any size of W states and hence is a universal tool for expanding entanglement. 相似文献
83.
Spinning detonation and velocity deficit in small diameter tubes 总被引:2,自引:0,他引:2
S. Kitano M. Fukao A. Susa N. Tsuboi A.K. Hayashi M. Koshi 《Proceedings of the Combustion Institute》2009,32(2):2355-2362
Detonation velocities and soot patterns of H2/O2 mixtures were measured in glass tubes of 3, 6 and 10 mm diameters at pressures ranging from 70 to 400 Torr and equivalence ratios of 0.5–1.5. It was confirmed that the transition from a multi-head to a spinning detonation occurred at the pressure where the cell size is equal to the length of circumference. At this transition pressure, the velocity was 95% of the C-J detonation. Stable spinning detonations were observed at wide range of initial pressures below the transition point. Detonation velocities were continuously decreasing with decreasing initial pressures in this pressure region. Spinning detonations with velocities down to 85% of the C-J detonation were observed. Those deficits in detonation velocities were well predicted by the modified ZND model with full detailed chemical kinetics. Heat and momentum losses were taking into account in this model. Validity of the modified ZND model to define the limit of detonation propagation was discussed. 相似文献
84.
85.
We investigate the possibility that both the baryon asymmetry of the universe and the observed cold dark matter density are generated by decays of a heavy scalar field which dominates the universe before nucleosynthesis. Since baryons and cold dark matter have common origin, this mechanism yields a natural explanation of the similarity of the corresponding energy densities. The cosmological moduli and gravitino problems are avoided. 相似文献
86.
87.
S. Matsuki K. Shimomura I. Ogawa K. Suzuki S. Hamada T. Nakamura H. Okuno M. Koizumi N. Inabe Y. Fukashiro H. Sunaoshi M. Wada T. Murayama T. Kohmoto M. Kitano T. Kubo T. Shinozuka K. Asahi Y. Kido T. T. Inamura T. Nomura M. Ishihara M. Fujioka H. T. Duong H. Haas 《Hyperfine Interactions》1992,74(1-4):223-239
Radiation-detected optical pumping in solids has been developed to investigate the structure of unstable nuclei. Appreciable
nuclear polarization of implanted or doped unstable-nuclei in a host crystal is achieved with the optical pumping in solids.
The nuclear polarization achieved is enhanced/reduced by applying a radio-frequency magnetic field together with the optical
pumping, radiation-detected magnetic resonance being thus observed to get information on electromagnetic properties of unstable
nuclei. Two schemes have been successfully developed for the optical pumping of unstable nuclei in solids. One is to directly
pump the atoms by the excitation from the ground state to a broad absorption band in visible and UV regions which shows a
large magnetic circular dichroism. This scheme is applicable to many rare-earth atoms in alkaline-earth fluoride host. The
other scheme is to pump the electrons in the conduction band of direct-type semiconductor and thus indirectly polarize the
nuclei in the host material via a hyperfine interaction between the nuclei and the polarized conduction electrons. This scheme
can be especially applied to the III to VI families of atoms in direct-type semiconductors. Principle of the methods, on-line
experimental system, and a few examples of the results obtained so far are presented and discussed. 相似文献
88.
89.
Chiba K Kono Y Kim S Nishimoto K Kitano Y Tada M 《Chemical communications (Cambridge, England)》2002,(16):1766-1767
Combinations of typical organic solvents composed of cyclohexane and qualified aprotic polar organic solvents were found to realize an effective, biphasic thermomorphic system in arbitrary ratios of upper and lower phases that enable a practical application of a liquid-phase peptide synthesis. 相似文献
90.
Takahiro Yamamoto Yasushi Maeda Seiichi Matsugo Hiromi Kitano 《Photochemistry and photobiology》1997,66(1):65-71
Abstract— Horseradish peroxidase (HRP) was photoirradiated in the presence of organic peroxide (1, hydroperoxynaphthalimide derivative) at around 353 nm and 0°C. This compound bound to a heme pocket of HRP as shown by its inhibitory effect on catalysis by HRP ( K i = 5.5 times 10−5 M) and subsequently it formed an intermediate in the same way as H202. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) suggested cleavage of the peptide chain of HRP on photoirradiation with 1. From CD spectra and SDS-PAGE, it was presumed that the destruction of both secondary structure and heme of the enzyme occurred to some extent upon photoirradiation, which resulted in a decrease in the catalytic activity. The absorption spectra also suggested that the heme group of the enzyme was destroyed, and the fluorescence spectra showed that the Trp residue in the photoirradiated HRP was oxidized to N -formylkynurenine by a hydroxyl radical generated from 1. Energy transfer from the excited naphthalimide moiety or hydrogen abstraction also seemed to make some contribution to the alteration of the heme group. 相似文献