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141.
Pressure effects on the Raman spectra due to the inter‐ and intramolecular vibrations of the L ‐ascorbic acid crystal were studied. The intensity of the Raman bands due to the intermolecular vibrations varies in three different ways by application of pressure. The bands of the first group become stronger, those of the second one become weaker and the third group shows no prominent change in their intensity with increasing pressure. The bands due to the intermolecular vibrations show a blue shift, while the bands due to the intramolecular vibrations shift to the blue or red depending on the vibrational modes by application of pressure. The bands assigned to the O H stretching vibrations shift to the red, the bands assigned to the CO and CC stretching vibrations shift a little to the red and the bands assigned to the other vibrations shift to the blue under high pressure. The following conclusions were derived. (1) The hydrogen bonds forming helixes become stronger and the isolated hydrogen bond becomes weaker with increasing pressure. (2) The bands of the first group owing to the intermolecular vibrations are ascribed to the vibrations related to the helix hydrogen bonds and the second group bands to the isolated hydrogen bond. (3) The CO stretching vibration couples with the CC stretching vibration. (4) The phase transitions take place at 1.8 and 4 GPa in the crystal. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
142.
Hideyuki Kihara Toshiaki Miura Ryoichi Kishi 《Macromolecular rapid communications》2004,25(2):445-449
Summary: Hydrogen‐bonded polymer films consisting of fine, extended fibers were prepared by photopolymerization of an acrylate monomer containing a benzoic acid group in the fingerprint or Grandjean textures of a cholesteric liquid‐crystalline mixture. Scanning electron microscopy and circular dichroism spectroscopy revealed that the fibers, measuring about 400 nm in diameter, formed helical superstructures and that their helical axes corresponded to the cholesteric helical axes that existed in the LC mixture before photopolymerization.
143.
Ryoichi Hiroi Suprakas Sinha Ray Masami Okamoto Takashi Shiroi 《Macromolecular rapid communications》2004,25(15):1359-1364
Summary: The preparation and characterization of a new type of nanocomposite material that is based on biodegradable polylactide (PLA) and organically modified layered titanate, is reported. Layered titanate, modified with a N‐(cocoalkyl)‐N,N‐[bis(2‐hydroxyethyl)]‐N‐methylammonium cation, was used as a new nanofiller (OHTO) for the nanocomposite preparation. Wide‐angle X‐ray diffraction and transmission electron microscopy (TEM) analyses confirmed that titanate layers were intercalated and nicely distributed in the PLA matrix. The materials properties of neat PLA improved remarkably after nanocomposite preparation.
144.
Eun Jeong Kim P. Ramesh Kumar Zachary T. Gossage Kei Kubota Tomooki Hosaka Ryoichi Tatara Shinichi Komaba 《Chemical science》2022,13(21):6121
Development of energy storage systems is a topic of broad societal and economic relevance, and lithium ion batteries (LIBs) are currently the most advanced electrochemical energy storage systems. However, concerns on the scarcity of lithium sources and consequently the expected price increase have driven the development of alternative energy storage systems beyond LIBs. In the search for sustainable and cost-effective technologies, sodium ion batteries (SIBs) and potassium ion batteries (PIBs) have attracted considerable attention. Here, a comprehensive review of ongoing studies on electrode materials for SIBs and PIBs is provided in comparison to those for LIBs, which include layered oxides, polyanion compounds and Prussian blue analogues for positive electrode materials, and carbon-based and alloy materials for negative electrode materials. The importance of the crystal structure for electrode materials is discussed with an emphasis placed on intrinsic and dynamic structural properties and electrochemistry associated with alkali metal ions. The key challenges for electrode materials as well as the interface/interphase between the electrolyte and electrode materials, and the corresponding strategies are also examined. The discussion and insights presented in this review can serve as a guide regarding where future investigations of SIBs and PIBs will be directed.The importance of the active material structure and the interface/interphase between the electrode and electrolyte in enhancing the electrochemical performance of sodium and potassium ion batteries. 相似文献
145.
146.
147.
A liquid pressure varifocus lens that consists of a thin polymer film and liquid is described. The lens can be continuously
changed from a concave to a convex shape by driving the liquid pressure in the lens. The dynamic range of the focal length
of the convex lens is from 50 to 250 mm. A beam spot verifies the variable focal function on a photographic film exposed by
a He-Ne laser. In addition, the application of the laser for processing is demonstrated to manufacture Fe compressed powder
sheets by normal pulse YAG laser. Its melting marks along a focus change are formed with a minimum width of 0.1 mm. 相似文献
148.
Yonezo Morino Mitsutoshi Tanimoto Shuji Saito Eizi Hirota Ryoichi Awata Takehiko Tanaka 《Journal of Molecular Spectroscopy》1983,98(2):331-348
Microwave spectra were observed for 14NO2 in the vibrationally excited ν1, ν2, ν3, and 2ν2 states, as well as for 15NO2 in the ν1 and ν2 states. The rotational constants, spin-rotation coupling constants and hyperfine interaction constants were precisely determined. Second-order change of the spin-rotation coupling constants with respect to the bending vibrational quantum number v2 was also determined. Combined use of the rotational constants obtained by the present microwave investigation and those reported in high-resolution infrared spectroscopic studies leads to the determination of all the vibration-rotation interaction constants αs and γss′ and the equilibrium structure of nitrogen dioxide, and θe (ONO) = 133°51.4′ ± 0.2′, in the second-order approximation with respect to the vibrational quantum numbers. 相似文献
149.
Koh Wada Makoto Kaburagi Takashi Uchida Ryoichi Kikuchi 《Journal of statistical physics》1988,53(5-6):1081-1101
The microscopic master equation of a system is derived within the framework of the path probability method (PPM). Then, by extending Morita's method in equilibrium statistical mechanics, the path probability function constructed microscopically can be systematically decomposed to result in the conventional path probability function of cluster approximation when correlations larger than the chosen basic cluster are neglected. In order to critically compare the master equation method with the PPM, the triangle approximation is treated by both methods for crystal growth models. It is found that the PPM gives physically satisfactory kinetic equations, while the master equation (supplemented with a cluster probability in the superposition approximation) does not. The triangle PPM calculation considerably improves the result of the pair approximation for crystal growth velocity in the solid-on-solid model, and compares well with Monte Carlo results. 相似文献
150.
Ryoichi Akaba Masaki Kamata Hirochika Sakuragi Katsumi Tokumaru 《Tetrahedron letters》1992,33(52):8105-8108
On the basis of measurements of rate constants for carbon-carbon bond cleavage of tetrakis(4-methylphenyl)ethanone cation radicals generated by pulsed laser excitation with sensitizers in solution, an SN1-type mechanism for the bond cleavage is proposed. 相似文献