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41.
Ludwik Synoradzki Marek Bolesławski Janusz Lewínski 《Journal of organometallic chemistry》1985,284(1):1-4
The reaction of diethylhydroxyborane with trialkylaluminium has been studied. Trialkylboranes and diethyltriisobutyldialuminium dioxide were isolated and characterized. A two-stage mechanism is proposed for the formation. 相似文献
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By examining some known wave equations it is shown that the dynamics of a free quantum particle in a slightly noncommutative space-time is equivalent to that of a charged particle moving in a self-generated (weak) electromagnetic field.Presented at the 5th International Colloquium on Quantum Groups: Quantum Groups and Integrable Systems, Prague, 20–22 June 1996. 相似文献
44.
Bartosz Trzaskowski Andrzej Le Abraham F. Jalbout Ludwik Adamowicz Per E.M. Siegbahn 《Journal of Molecular Structure》2007,820(1-3):90-97
A density-functional-theory investigation of the nonenzymatic solvolysis of the cytydine 5′-monophosphate N-acetylneuraminic acid and its derivatives in the acidic environment is presented. The theoretical calculations of the second stage of the reaction mechanism are in agreement with the hypothesis of a dissociative oxocarbenium-like transition state with proton transfer as a key part of the reaction. The geometries of the transition states of the reactions yielding -methyl and β-methyl glycosides are essentially different. This study provides new theoretical data that can be helpful in elucidating the mechanism of the carbohydrates hydrolysis as well as other reactions catalyzed by the glycosyltransferases. 相似文献
45.
Krzysztof Bujnowski Ludwik SynoradzkiEckhard Dinjus Thomas ZevacoEwa Augustynowicz-Kope? Zofia Zwolska 《Tetrahedron》2003,59(11):1885-1893
Within the study covering the search for new methods of synthesis of rifamycin antibiotics, the reactions of 3-formylrifamycin SV (2) with primary amines or ammonia were studied. In the reaction of 2 with methylamine, unstable 3-methyliminomethylrifamycin SV (8) was formed, which was further oxidised to stable 3-methyliminomethylrifamycin S (9). In the reaction of 2 with ammonia, N,15-didehydro-15-deoxo-pyrimido-(4,5-b)rifamycin SV (10), a new compound with a chromophore system enlarged by a pyrimidine ring, was obtained. The product of its reduction with sodium borohydride—(11)—was also isolated. The structures of the compounds and an explanation of the synthesis mechanism have been proposed on the basis of mass spectrometry results as well as (1D) and (2D) 1H- and 13C NMR analysis. In vitro antituberculous activity of the new compounds have been investigated. 相似文献
46.
Dmitry I. Lyakh Vladimir V. Ivanov Ludwik Adamowicz 《Theoretical chemistry accounts》2006,116(4-5):427-433
An algorithm for generation of the spin-orbital diagrammatic representation, the corresponding algebraical formulas, and the computer code of the coupled cluster (CC) method with an arbitrary level of the electronic excitations developed earlier in our laboratory have been employed to generate the CAS(2,2)CCSD code. CAS(2,2)CCSD is the state-specific, multireference coupled cluster (SSMRCC) approach with single and double excitations based on the CASSCF(2,2) reference wave function. The CAS(2,2)CCSD was used to describe the model process of inserting the Be atom into the H2 molecule. We show that our method performs better than the “fully-blown” SSMRCC approach of Mukherjee and coworkers (J Chem Phys 110:6171, 1999). 相似文献
47.
Self-consistent electrostatic intersite potentials and atomic charges have been calculated. Lattice cohesion energy for NaTCNQ has been reproduced when polarization of TCNQ- anion in the lattice was taken into account. 相似文献
48.
Damien Montarnal François Tournilhac Manuel Hidalgo Ludwik Leibler 《Journal of polymer science. Part A, Polymer chemistry》2010,48(5):1133-1141
We combine the supramolecular chemistry of heterocyclic ureas with the chemistry of epoxides to synthesize new crosslinked materials incorporating both chemical and supramolecular hydrogen‐bonded links. A two‐step facile and solvent‐free procedure is used to obtain chemically and thermally stable networks from widely available ingredients: epoxy resins and fatty acids. The density of both chemical and physical crosslinks is controlled by the stoichiometry of the reactants and the use of a proper catalyst to limit side reactions. Depending on the stoichiometry, a wide range of thermomechanical properties can be attained. The method can be used to produce elastomeric objects of complex shapes. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1133–1141, 2010 相似文献
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Ludwik Kranz Edyta N. Osika Serajum Monir Yu-Ling Hsueh Lukas Fricke Samuel J. Hile Yousun Chung Joris G. Keizer Rajib Rahman Michelle Y. Simmons 《Advanced functional materials》2024,34(8):2307285
Precision-placed atom qubits in silicon offer a unique means to confine electrons and control their spins with extreme accuracy, which can be leveraged to construct powerful quantum computers. To date atom qubits in silicon have been successfully realized using electrons hosted either on a single phosphorus atom or on a multi-donor quantum dot. Here, a novel molecular regime is explored in which electrons are bound to two donor dots separated by ≈8 nm in a natural silicon substrate. The molecular state, provided by these spatially separated donors, is used to study with exquisite precision the impact of confinement potential on the electronic and spin properties of qubits. Unique spin filling measurements, performed on up to five electrons, confirm how electrons are shared between both sites of the molecule, forming hybridized molecular states. The precise atomic locations of the donor atoms in the silicon lattice are determined by combining the experimental electron spin resonance spectra and the state-of-the-art atomistic modeling of multi-electron wave-functions in presence of realistic electric fields. The donor molecule studied in this work exhibits excellent qubit properties and addresses the impact that the confinement potential has, at the atomic scale, on the desired properties of electron spin qubits. 相似文献