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91.
S. Cordier F. Dorson F. Grasset Y. Molard B. Fabre H. Haneda T. Sasaki M. Mortier S. Ababou-Girard C. Perrin 《Journal of Cluster Science》2009,20(1):9-21
In this contribution, we present a review of our recent works about the design of phosphor nanoparticles and materials based
on [Mo6X14]2− cluster units (X = Cl, Br, I) as well as the functionalization of monocrystalline Si(111) surfaces by Mo6 clusters. Our purpose was to use the specific properties of cluster units found in inorganic solids for the design of new
nanomaterials with potential applications in nanotechnologies (e.g. phosphor dyes for bio labelling, light emitting diodes,
redox active molecular junctions…) using soft chemistry techniques. Phosphor Cs2Mo6X14@SiO2 nanoparticles emitting in 550–900 nm upon photo-excitation were synthesised using a ‘water in oil’ microemulsion technique.
They exhibit a regular shape (~45 nm) and are based on [Mo6X14]2− cluster units and Cs+ counter cations embedded in a silica matrix. ((n–C4H9)4N)2Mo6Br14@ZnO colloids and nanopowders are based on the association of ZnO crystalline nano-particles with Mo6 cluster units adsorbed on their surface. They exhibit a large emission window in the visible region that can be tuned by
modulation of the excitation wave length in order to selectively obtain the emission of either clusters units or ZnO nanocrystals
or of both entities. Functionalized surfaces were obtained by the attachment of cluster units on a Si(111) surface through
pyridine end capped organic chains using a multi-step procedure. Modified surfaces were characterized by X-ray photoemission
spectroscopy (XPS), atomic force microscopy (AFM), IR and electrochemical analysis. The surface coverage can be modulated
by the controlled introduction of inert organic chains among pyridine end-capped ones before the cluster anchoring step. 相似文献
92.
Haruka Kawade Jyoji Morise Sushil K. Mishra Shuta Tsujioka Shogo Oka Yasuhiko Kizuka 《Molecules (Basel, Switzerland)》2021,26(17)
Human natural killer—1 (HNK-1) is a sulfated glyco-epitope regulating cell adhesion and synaptic functions. HNK-1 and its non-sulfated forms, which are specifically expressed in the brain and the kidney, respectively, are distinctly biosynthesized by two homologous glycosyltransferases: GlcAT-P in the brain and GlcAT-S in the kidney. However, it is largely unclear how the activity of these isozymes is regulated in vivo. We recently found that bisecting GlcNAc, a branching sugar in N-glycan, suppresses both GlcAT-P activity and HNK-1 expression in the brain. Here, we observed that the expression of non-sulfated HNK-1 in the kidney is unexpectedly unaltered in mutant mice lacking bisecting GlcNAc. This suggests that the biosynthesis of HNK-1 in the brain and the kidney are differentially regulated by bisecting GlcNAc. Mechanistically, in vitro activity assays demonstrated that bisecting GlcNAc inhibits the activity of GlcAT-P but not that of GlcAT-S. Furthermore, molecular dynamics simulation showed that GlcAT-P binds poorly to bisected N-glycan substrates, whereas GlcAT-S binds similarly to bisected and non-bisected N-glycans. These findings revealed the difference of the highly homologous isozymes for HNK-1 synthesis, highlighting the novel mechanism of the tissue-specific regulation of HNK-1 synthesis by bisecting GlcNAc. 相似文献
93.
Yasuhiko Syono Atsuko Ito Setsu Morimoto 《Journal of Physics and Chemistry of Solids》1981,42(6):483-486
The Mössbauer spectra of ilmenite (FeTiO3), Fe2+-doped ilmenites, MTiO3 (M = Cd, Mn, Zn, Co, Mg and Ni) and MGeO3 (M = Mn, Zn and Mg), have been studied from 4.2 K to room temperature. Systematic variations in the isomer shift and quadrupole splitting at room temperature are correlated with the change in ionic radii of the host M ions and the c/a ratio of the host crystal, respectively. The quadrupole splittings show a remarkable temperature variation; the magnetic ilmenites show either a sudden increase or a sudden decrease of quadrupole splittings below the Néel temperature, depending on the orientation of the spin axis with respect to the c axis. 相似文献
94.
JS Park Y Hirana S Mouri Y Miyauchi N Nakashima K Matsuda 《Journal of the American Chemical Society》2012,134(35):14461-14466
Understanding of electronic and optical features of single-walled carbon nanotubes (SWNTs) has been a central issue in science and nanotechnology of carbon nanotubes. We describe the detection of both the positive trion (positively charged exciton) and negative trion (negatively charged exciton) as a three-particle bound state in the SWNTs at room temperature by an in situ photoluminescence spectroelectrochemistry method for an isolated SWNT film cast on an ITO electrode. The electrochemical hole and electron dopings enable us to detect such trions on the SWNTs. The large energy difference between the singlet bright exciton and the negative and positive trions showing a tube diameter dependence is determined by both the exchange splitting energy and the trion binding energy. In contrast to conventional compound semiconductors, on the SWNTs, the negative trion has almost the same binding energy to the positive trion, which is attributed to nearly identical effective masses of the holes and electrons. 相似文献
95.
Ken Watanabe Kenji Matsumoto Yutaka Adachi Takeshi Ohgaki Tsubasa Nakagawa Naoki Ohashi Hajime Haneda Isao Sakaguchi 《Solid State Communications》2012,152(20):1917-1920
Isotopic ZnO thin films were deposited on the c-plane of ZnO single crystals by pulsed laser deposition. The isotopic abundance of Zn in the films was determined with a secondary ion mass spectrometry before and after the films was diffusion annealed. The diffusion profiles across the film/substrate interface behaved smooth features. The zinc diffusion coefficient (DZn) was obtained by analyzing the slope of the profile in the annealed sample. The temperature dependence of DZn was determined to be DZn(cm2/s)=8.0×104exp(?417[kJ/mol])/RT, where R and T are gas constant and temperature. The zinc ion diffusion coefficients were of the same order as that in a ZnO single crystal. A comparison of the experimental and theoretical values indicated that the zinc ions diffused in the thin film and the single crystal through a vacancy mechanism. 相似文献
96.
Hyung Woo Choi Yasuhiko Sakata Yoshikazu Kurihara Tooru Ooya Toshifumi Takeuchi 《Analytica chimica acta》2012
Reflectometric interference spectroscopy (RIfS) is a label-free, time-resolved technique, and suitable for detecting antibody–antigen interaction. This work describes a continuous flow biosensor for C-reactive protein (CRP), involving an effective immobilization method of a monoclonal antibody against CRP (anti-CRP) to achieve highly sensitive RIfS-based detection of CRP. The silicon nitride-coated silicon chip (SiN chip) for the RIfS sensing was first treated with trimethylsilylchloride (TMS), followed by UV-light irradiation to in situ generation of homogeneous silanols on the surface. Following amination by 3-aminopropyltriethoxysilane, carboxymethyldextran (CMD) was grafted, and subsequently, protein A was immobilized to create the oriented anti-CRP surface. The immobilization process of protein A and anti-CRP was monitored with the RIfS system by consecutive injections of an amine coupling reagent, protein A and anti-CRP, respectively, to confirm the progress of each step in real time. The sensitivity was enhanced when all of the processes were adopted, suggesting that the oriented immobilization of anti-CRP via protein A that was coupled with the grafted CMD on the aminated surface of TMS-treated SiN chip. The feasibility of the present sensing system was demonstrated on the detection of CRP, where the silicon-based inexpensive chips and the simple optical setup were employed. It can be applied to other target molecules in various fields of life science as a substitute of surface plasmon resonance-based expensive sensors. 相似文献
97.
Debasish Ghosh Pradip Ghosh Mohd Zamri Yusop Masaki Tanemura Yasuhiko Hayashi Tetsuo Tsuchiya Tomohiko Nakajima 《固体物理学:研究快报》2012,6(7):303-305
A fully transparent and flexible field emission device (FED) has been demonstrated. Single‐walled carbon nanotubes (SWCNTs) coated on arylite substrate were used as electron emitters for the FED and a novel metavanadate phosphor coated on the SWCNTs/arylite film was used as transparent and flexible screen. The SWCNTs/arylite based emitters and the SWCNTs/arylite/metal‐vanadate‐based phosphor showed a transmittance value of 92.6% and 54%, respectively. The assembled device also showed satisfactory transparency and flexibility as well as producing significant current. Metavanadate phosphor is considered to be an excellent candidate due to its superior luminescence properties and easy fabrication onto transparent and flexible conductive substrate at room temperature while retaining reasonable transparency of the substrate. Thus, its transparency and flexibility will open the door to next‐generation FEDs. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
98.
Katsuyoshi Kakinuma Hiroshi Yamamura Hajime Haneda Tooru Atake 《Solid State Ionics》2001,140(3-4):301-306
(Ba1−xLax)2In2O5+x, whose end member is Ba2In2O5, is an oxygen-deficient perovskite oxide showing high oxide-ion conductivity. In order to clarify the reason why the high oxide ion conductivity appeared in this system, the electrical conductivity was measured as a function of temperature and La content. With an increasing La content, the discontinuous jump of ion conductivity in the Arrhenius plot, which is related to the disordering of the oxygen vacancies, disappeared for the sample with x0.2. Above x=0.12, the ion conductivity linearly increased with La content, while the activation energy remained constant with respect to the La content. Moreover, the conductivity for x=0.6 was 0.042 (S/cm) at 1073 K, which exceeded that of 8 mol% yttria-stabilized zirconia. The higher oxide-ion conductivity of this system could be dominated by the amount of mobile oxygen ions. 相似文献
99.
Kazuhiko Matsumoto Rika Hagiwara Yasuhiko Ito Osamu Tamada 《Journal of fluorine chemistry》2001,110(2):117-122
Structures of AgAF6 (A=Sb, Ta) have been determined by X-ray single crystal studies at ambient temperatures. AgSbF6 crystallizes in space group Ia
with a=979.85(4) pm, V=9.4076(12)×108 pm3, z=8, and AgTaF6 crystallizes in space group P42/mcm with a=499.49(4) pm, c=960.51(8) pm, V=2.3964(6)×108 pm3, z=2. Only the crystal system and cell parameters were obtained for the isomorphic AgNbF6; primitive tetragonal, a=497.80(10) pm, b=960.40(10) pm, V=2.3799(12)×108 pm3, z=2. The results of the Raman spectroscopy of AgAF6 support the obtained structures. The structures are discussed by comparing with that of AgPF6 and AgAsF6 which have recently been determined in a series of our study. 相似文献
100.
The promotion of sulfur oxides on the selective catalytic reduction (SCR) of NO by hydrocarbons in the presence of a low concentration of sulfur oxides over Ag/Al2O3 has been investigated by a flow reaction test and in situ infrared spectroscopy. When the C3H6 (or C10H22) + NO + O2 feed-flow reaction was tested, maximum NO reduction was below 30% over fresh Ag/Al2O3. After the addition of SO2 to the feed flow, conversion increased slightly. Conversion increased further after SO2 was cut-off from the feed flow. This demonstrated that the increase in NO reduction activity of the catalyst was related to SOx adsorbed on the catalyst. SOx adsorbed on the catalytic surface (1375 cm−1) was detected by IR spectroscopy and was stable within the temperature range. NCO species, as an intermediate in NO reduction, on SOx-adsorbed Ag/Al2O3 in a C3H6 + NO + O2 feed flow was observed in in situ IR spectra during the elevation of the reaction temperature from 473 to 673 K, while it was only observed at 673 K on fresh Ag/Al2O3 under the same experimental conditions. We suggest that SOx in low concentrations depressed the combustion of reductants by contaminating hydrocarbon combustion active sites on the catalyst, resulting in an increase in NO reduction efficiency of the reductants. 相似文献