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31.
The optoacoustic method has been shown to be an accurate technique for the measurement of the properties of submicron metal coatings deposited on a dielectric substrate, i.e., mirrors. The method has been previously theoretically described in terms of a linear model of optoacoustic transformation in a system substrate/coating/liquid. The goal of the present work was to determine the limits at which the linear model is still applicable. The modification of the laser induced acoustic signal profiles and transfer functions of optoacoustic transformation versus the laser fluence was studied for two liquids: ethanol and water. 相似文献
32.
We investigate the stability of some inequalities of isoperimetric type related to Monge–Ampère functionals. In particular, firstly we prove the stability of a reverse Faber–Krahn inequality for the Monge–Ampère eigenvalue and its generalization. Then we give a stability result for the Brunn–Minkowski inequality and for a consequent Urysohn’s type inequality for the so-called \(n\) -torsional rigidity, a natural extension of the usual torsional rigidity. 相似文献
33.
Daria V. Chernysheva Victor A. Klushin Alexander F. Zubenko Lyudmila S. Pudova Oleg A. Kravchenko Victor M. Chernyshev Nina V. Smirnova 《Mendeleev Communications》2018,28(4):431-433
The Pt/C catalysts with various Pt content (5-30 wt%) synthesized via electrochemical pulse alternating current technique have been evaluated for the base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. The higher Pt content in the catalyst (30 wt%) provides the product yield up to 65% upon performing the process in concentrated (~0.1 M) aqueous solutions of the substrate. 相似文献
34.
35.
Daria V. Berdnikova Olga A. Fedorova Elena V. Tulyakova Haixing Li Sarah Kölsch Heiko Ihmels 《Photochemistry and photobiology》2015,91(3):723-731
DNA‐binding properties of 15‐crown‐5‐derived mono‐ and bis‐styryl dyes were investigated in the presence of calf thymus DNA. To access the factors that influence the DNA association in the series of these ligands, the structure of the molecules was varied by either changing size of the heterocyclic moiety or altering the position of the styryl substituents. The major binding mode for the monostyryl dyes is intercalation. Notably, binding of the dyes to the nucleic acids leads to a fluorescence enhancement by a factor of up to 54. Therefore, these cationic styryl derivatives may be applied as fluorescent “light‐up” probes for DNA detection. 相似文献
36.
The PBE0/6-31G** quantum chemical method is used to determine the symmetry and equilibrium structural parameters of the molecules
of [1.1.1.1]pagodane (C20H20, D
2h
), two dienes (C20H20, D
2h
), two diradicals (C20H20, C
2ν
), and two dications (C20H202+, D
2h
and C
2ν
). The energy of a highly symmetric dication with a rectangular cycle is lower by 36 kcal/mole than that of a low symmetric
dication with a trapezoidal cycle. The polarization interaction with liquid methylene chloride causes its decrease by 147
kcal/mole. 相似文献
37.
The influence of polydispersity on the interfacial kinetics of end-coupling and microstructure formation in the melt of immiscible polymers was studied using dissipative particle dynamics simulations. The irreversible reaction started at a flat interface between two layers, each of which contained polymer chains of two different lengths with functionalized or unreactive end groups. As in the case of fully functionalized monodisperse reactants [A. V. Berezkin and Y. V. Kudryavtsev, Macromolecules 44, 112 (2011)], four kinetic regimes were observed: linear (mean field coupling at the initial interface), saturation (decreasing the reaction rate due to the copolymer brush formation or reactant depletion near the interface), autocatalytic (loss of the initial interface stability and formation of a lamellar microstructure), and terminal (microstructure ripening under diffusion control). The interfacial instability is caused by overcrowding the interface with the reaction product, and it can be kinetically suppressed by increasing chain length of the reactants. Main effects of polydispersity are as follows: (i) the overall end-coupling rate is dominated by the shortest reactive chains; (ii) the copolymer concentration at the interface causing its instability can be not the same as in the lamellas formed afterwards; (iii) mean length of the copolymer product considerably changes with conversion passing through a minimum when a microstructure is just formed. 相似文献
38.
Jakes P Erdem E Ozarowski A van Tol J Buckan R Mikhailova D Ehrenberg H Eichel RA 《Physical chemistry chemical physics : PCCP》2011,13(20):9344-9352
The local coordination of the Fe(3+)-centers in Li[Co(0.98)Fe(0.02)]O(2) cathode materials for lithium-ion batteries has been investigated by means of XRD and multi-frequency EPR spectroscopy. EPR clearly showed the Fe(3+) being in a high-spin state with S = 5/2. The set of spin-Hamiltonian parameters obtained from multi-frequency EPR experiments with Larmor frequencies ranging between 9.8 and 406 GHz was transformed into structural information by means of an expansion to standard Newton-superposition modeling, termed as Monte-Carlo Newman superposition modeling. Based on this analysis, an isovalent incorporation of the Fe(3+)-ions on the Co(3+)-sites, i.e. Fe(x)(Co), has been shown. With that respect, the positive sign of the axial second-order fine-structure interaction parameter B(0)(2) is indicative of an elongated oxygen octahedron, whereas B(0)(2) < 0 points to a compressed octahedron coordinated about the Fe(3+)-center. Furthermore, the results obtained here suggest that the oxygen octahedron about the Fe(3+)-ion is slightly distorted as compared to the CoO(6) octahedron, which in turn may impose mechanical strain to the cathode material. 相似文献
39.
Brian E. Broderick Wim P. Cofino Rita Cornelis Kaj Heydorn William Horwitz David T. E. Hunt Robert C. Hutton Howard M. Kingston Herbert Muntau Renato Baudo Daria Rossi Jacobus G. van Raaphorst Tjip T. Lub Peter Schramel Frank T. Smyth David E. Wells Allan G. Kelly 《Mikrochimica acta》1991,104(1-6):523-542
The Euroanalysis VII conference in Vienna included a two-day session: Quality Assurance in Analytical Chemistry. The contributions comprised 15 lectures devoted to: intra-laboratory quality measures, inter-laboratory control, formal aspects and accreditation and implementation. The paper presents an overview of the main items developed by the contributors.A survey on the session on Quality Assurance in Analytical Chemistry of Euroanalysis VIIThe authors thank the organizers of EUROANALYSIS VII and in particular Dr. B. Griepink and Dr. E. Maier of the Community Bureau of Reference (BCR) of the CEC for their support and considerable contributions. 相似文献
40.