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101.
Masao Ichida Shingo Saito Ye Feng Kazuhiro Yanagi Hiroaki Ando 《Solid State Communications》2011,151(22):1696-1699
Absorption spectra of high purity metallic and semiconducting single-walled carbon nanotubes separated by the density-gradient ultracentrifugation method have been measured in the wide energy region from 1 meV to 5 eV. In the high purity metallic nanotube sample, a strong and broad absorption band has been observed at 0.06 eV. This observation suggests that the optical properties of even high purity metallic nanotube bundles cannot be explained by the simple Drude conduction model. We discuss the origin of these absorption bands for metallic and semiconducting nanotube samples by considering the existence of a small energy gap in metallic nanotube bundles and plasmon resonance. 相似文献
102.
We give an upper bound for the alternation number of a torus knot which is of either 3-, 4-, or 5-braid or of other special types. Using the inequality relating the alternation number, signature, and Rasmussen s-invariant, discovered by Abe, we determine the alternation numbers of the torus knots T(3,l), , and T(4,5). Also, for any positive integer k we construct infinitely many 3-braid knots with alternation number k. 相似文献
103.
Taizo Hatta Muneob Kawano Hironori Maeda Otohiko Tsuge 《Journal of heterocyclic chemistry》1997,34(2):579-583
The reaction of 5-bromomethyl-3-(p-bromomethylphenyl)isoxazole with o-, m-, and p-bis(mercap-tomethyl)benzenes gave the corresponding dithia- and/or tetrathiaisoxazolophanes, whose relative yields strongly depended upon the nature of the mercaptomethyl compound. The above isoxazole dibromide reacted with the bis(mercaptomethyl)isoxazole to afford a mixture of two isomeric dithiaisoxazolophanes. 相似文献
104.
Masao Ichida Satoshi Sakoda Yumie Kiyohara Singo Saito Yasumitsu Miyata Hiromichi Kataura Ken-ichi Mizuno Hiroaki Ando 《Journal of luminescence》2008,128(5-6):952-955
We have studied 1D exciton relaxation dynamics in semiconducting single-walled carbon nanotubes (SWNTs) by femtosecond pump–probe experiments. The time evolution of change in transmittance ΔT/T induced by photo-excitation varies depending on the tube diameter. The decay time decreases with a decrease in the tube diameter. Pressure measurements have been conducted to explore the relaxation mechanism. The deformation potential estimated from the pressure dependence of photoluminescence spectra increases with decreasing tube diameter. This means that the exciton–phonon interaction becomes stronger in the smaller diameter tubes. The diameter dependences of decay time and deformation potential suggest that the exciton–phonon interaction plays an important role in exciton nonradiative relaxation process in semiconducting SWNTs. 相似文献
105.
Taizo Watanabe Yuhsi Matuo Takao Mori Ryujiro Sano Tetsuya Tosa Ichiro Chibata 《Applied biochemistry and biotechnology》1978,3(3):161-174
Preparation and adsorption specificity of tannins immobilized by covalent binding on water-insoluble matrices were investigated. Immobilized tannins were prepared by condensing cyanogen bromide activated tannins with aminohexyl derivatives of several kinds of matrices. The most suitable matrix for the immobilization of tannin was alkali-treated cellulose powder. The concentration of sodium hydroxide solution for alkali treatment influenced the adsorption capacity of immobilized tannin for a protein, but temperature and time for alkali treatment did not. Immobilized tannins having spacers of long chain length exhibited high adsorption capacity for a protein. Chinese gallotannin was the most favorable ligand for protein adsorption. The immobilization of tannin on aminohexyl matrices was also possible by using epichlorohydrin instead of cyanogen bromide. The maximum adsorption capacity of the immobilized tannin for a protein was about 50 mg/ml of the absorbent. Immobilized tannin adsorbed proteins specifically but did not absorb low molecular weight compounds. 相似文献
106.
107.
We consider the dimer problem on a planar non-bipartite graph G, where there are two types of dimers one of which we regard as impurities. Computer simulations reveal a reminiscence of
the Cheerios effect, that is, impurities are attracted to the boundary, which is the motivation to study this particular graph.
Our main theorem is a variant of the Temperley bijection: a bijection between the set of dimer coverings and the set of spanning
forests with certain conditions. We further discuss some implications of this theorem: (1) the local move connectedness yielding
an ergodic Markov chain on the set of all possible dimer coverings, and (2) a rough bound for the number of dimer coverings
and that for the probability of finding an impurity at a given edge, which is an extension of a result in (Nakano and Sadahiro
in ). 相似文献
108.
Hidetaka Kasai Taizo Kawauchi Xiao-Wei Zhang Takumi Kikegawa Tatsuo Okano 《Applied Surface Science》2009,256(4):984-986
We applied the time-domain analysis of nuclear resonant scattering (NRS) of X-rays for the study of the hydrogen-induced enhancement of atomic diffusion. The time-domain analysis of NRS is a powerful technique for studying diffusion processes on an atomic scale. The NRS measurement combined with high-pressure technique enables the direct measurement of self-diffusion processes under high hydrogen pressures. In this preliminary experiment, self-diffusion in 4 μm thick 57Fe foils at 0.8 GPa was investigated. The samples of the 57Fe were encapsulated with MgO or NaCl. Faster decays caused by diffusion of Fe atoms were observed in the time spectra of NRS at high temperatures. This enhancement of diffusion is believed to be the hydrogen-induced effect. In the present experiment, hydrogen should have been supplied to the samples by reaction with water originally adsorbed on NaCl/MgO powder particles. It was concluded that the diffusion of 57Fe atoms under high pressure can be studied by nuclear resonant scattering of X-rays using a compact cubic-anvil press. The NRS method can also be extended to the study of atomic diffusion in the subsurface region by doping 57Fe layer(s) at known depths. 相似文献
109.
Nakamura R Hamada N Ichida H Tokunaga F Kanematsu Y 《Photochemistry and photobiology》2008,84(4):937-940
The ultrafast photo-induced dynamics of wild-type photoactive yellow protein and its site-directed mutant of E46Q in aqueous solution was studied at room temperature by femtosecond fluorescence spectroscopy using the optical Kerr-gate method. The vibronic structure appears, depending on the excitation photon energy, in the time-resolved fluorescence spectra just after photoexcitation, which winds with time and disappears on a time scale of sub-picoseconds. This result indicates that the wavepacket is localized in the electronic excited state followed by dumped oscillations and broadening, and also that the initial condition of the wavepacket prepared depending on the excitation photon energy affects much the following ultrafast dynamics in the electronic excited state. 相似文献
110.