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471.
Synthesis of the P-sulfide derivatives of 3-phosphabicyclo[3.1.0]hexanes and 1,2-dihydrophosphinines
Gyrgy Keglevich Lszl Tke Csaba Lovsz Klmn Újszszy Gbor Szalontai 《Heteroatom Chemistry》1994,5(4):395-401
Several 3-phosphabicyclo[3.1.0]hexane 3-oxides have been transformed into the corresponding sulfides by reaction with phosphorus pentasulfide. The 3-phenyl derivative could also be prepared by deoxygenation of the oxide followed by reaction with elemental sulfur. Opening of the cyclopropane ring in phosphabicyclohexane sulfides afforded mixtures of 3- and 5-methyl-1,2-dihydro-phosphinine-1-sulfides. Because of better yields, preparation of these products by thionation of the dihydrophosphinine oxides is more appropriate. The new phosphorus heterocycles have been characterized by 31P, 13C, and 1H NMR and mass spectral data. 相似文献
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474.
Mrta Berkesi Kroly Hidas Tibor Guzmics Jean Dubessy Robert J. Bodnar Csaba Szab Balzs Vajna Toshiaki Tsunogae 《Journal of Raman spectroscopy : JRS》2009,40(11):1461-1463
Raman spectroscopic analysis at low (−100 °C) or high (100–200 °C) temperature is shown to be effective for detecting small amounts of H2O in CO2‐rich fluid inclusions from the deep lithosphere, which have previously been thought to be water‐free. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
475.
Balázs Szathmári Dr. Csaba Fekete Dr. Zsolt Kelemen Dr. Tamás Holczbauer Prof. László Nyulászi Dr. Ilona Kovács 《欧洲无机化学杂志》2023,26(28):e202300316
The reduction of 1,1-dichloro-2,5-bistrimethylsilyl-3,4-diphenylsilole to silolide dianion by alkali metals was investigated. As previously demonstrated, the outcome of the reaction depends strongly on the applied alkali metal, solvent, reaction conditions, and substituent pattern. We showed that lithium is a powerful reducing agent in THF or DME solvents, the reaction is even faster than the same reaction with sodium. The X-ray structures of the corresponding dilithio and disodium silolide dianion were investigated, interestingly recrystallization of the dilithio salt results in a coordination polymer. In order to support the synthetic work DFT calculations were performed. 相似文献
476.
Hugo A. Akitaya Matthew D. Jones Matias Korman Oliver Korten Christopher Meierfrankenfeld Michael J. Munje Diane L. Souvaine Michael Thramann Csaba D. Tóth 《Journal of Graph Theory》2023,102(1):35-66
Motivated by recent computational models for redistricting and detection of gerrymandering, we study the following problem on graph partitions. Given a graph and an integer , a -district map of is a partition of into nonempty subsets, called districts, each of which induces a connected subgraph of . A switch is an operation that modifies a -district map by reassigning a subset of vertices from one district to an adjacent district; a 1-switch is a switch that moves a single vertex. We study the connectivity of the configuration space of all -district maps of a graph under 1-switch operations. We give a combinatorial characterization for the connectedness of this space that can be tested efficiently. We prove that it is PSPACE-complete to decide whether there exists a sequence of 1-switches that takes a given -district map into another; and NP-hard to find the shortest such sequence (even if a sequence of polynomial lengths is known to exist). We also present efficient algorithms for computing a sequence of 1-switches that take a given -district map into another when the space is connected, and show that these algorithms perform a worst-case optimal number of switches up to constant factors. 相似文献
477.
Irén Simkó Christoph Schran Fabien Brieuc Csaba Fábri Oskar Asvany Stephan Schlemmer Dominik Marx Attila G. Császár 《Angewandte Chemie (International ed. in English)》2023,62(41):e202306744
Quantum mechanics dictates that nuclei must undergo some delocalization. In this work, emergence of quantum nuclear delocalization and its rovibrational fingerprints are discussed for the case of the van der Waals complex . The equilibrium structure of is planar and T-shaped, one He atom solvating the quasi-linear He−H+−He core. The dynamical structure of , in all of its bound states, is fundamentally different. As revealed by spatial distribution functions and nuclear densities, during the vibrations of the molecule the solvating He is not restricted to be in the plane defined by the instantaneously bent chomophore, but freely orbits the central proton, forming a three-dimensional torus around the chromophore. This quantum delocalization is observed for all vibrational states, the type of vibrational excitation being reflected in the topology of the nodal surfaces in the nuclear densities, showing, for example, that intramolecular bending involves excitation along the circumference of the torus. 相似文献