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101.
Fabien Mançois Jean‐Luc Pozzo Prof. Jianfeng Pan Dr. Frédéric Adamietz Vincent Rodriguez Prof. Laurent Ducasse Dr. Frédéric Castet Dr. Aurélie Plaquet Benoît Champagne Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(11):2560-2571
Molecular switches : Highly efficient acido‐ and photoswitchable frequency doublers (see scheme) based on the indolinooxazolidine core are studied by means of hyper‐Rayleigh experiments and quantum‐chemical calculations.
102.
103.
Flavia Bonomo Guillermo Durán Frederic Maffray Javier Marenco Mario Valencia-Pabon 《Graphs and Combinatorics》2009,25(2):153-167
A b-coloring of a graph is a coloring such that every color class admits a vertex adjacent to at least one vertex receiving each of the
colors not assigned to it. The b-chromatic number of a graph G, denoted by χ
b
(G), is the maximum number t such that G admits a b-coloring with t colors. A graph G is b-continuous if it admits a b-coloring with t colors, for every . We define a graph G to be b-monotonic if χ
b
(H
1) ≥ χ
b
(H
2) for every induced subgraph H
1 of G, and every induced subgraph H
2 of H
1. In this work, we prove that P
4-sparse graphs (and, in particular, cographs) are b-continuous and b-monotonic. Besides, we describe a dynamic programming
algorithm to compute the b-chromatic number in polynomial time within these graph classes.
Flavia Bonomo: Partially supported by ANPCyT PICT-2007-00533 and PICT-2007-00518, and UBACyT Grants X069 and X606 (Argentina).
Guillermo Durán: Partially supported by FONDECyT Grant 1080286 and Millennium Science Institute “Complex Engineering Systems”
(Chile), and ANPCyT PICT-2007-00518 and UBACyT Grant X069 (Argentina).
Javier Marenco: Partially supported by ANPCyT PICT-2007-00518 and UBACyT Grant X069 (Argentina). 相似文献
104.
Martin Obadal Roman ?ermák Vincent Verney Frederic Fraïsse 《Polymer Degradation and Stability》2006,91(3):459-463
The effects of UV irradiation on β-nucleated injection-moulded polypropylenes (β-iPP) have been studied at several structural levels. Commercially available isotactic polypropylene was modified by 0.03 wt.% β-nucleating agent based on N,N′-dicyclohexylnaphthalene-2,6-dicarboxamide. β-iPP specimens were injection-moulded using a processing set-up in which only mould temperature was varied. It was found that specimens consisted of a skin-core structure, which was strongly influenced by varying mould temperatures. The structural development consequently affected the specimen degradability as shown by wide-angle X-ray scattering, light microscopy and micro-infrared microscopy. 相似文献
105.
This paper presents recent improvement on sound velocity measurements under extreme conditions, illustrated by the hypersonic sound velocity measurements of water up to 723 K and 9 GPa using Brillouin scattering technique. Because water at high pressure and high temperature is chemically very aggressive, these experiments have been carried out using a specific experimental set-up. The present data should be useful to better constrain the water equation of state at high density. This new development brings high-quality elastic data in a large pressure/temperature domain, which may afterwards benefit the understanding of many other fields as nonlinear acoustics, underwater sound, or physical acoustics from a more general point of view. 相似文献
106.
Louis Pergaud Sandjo Victor Kuete Frederic Nana Gilbert Kirsch Thomas Efferth 《Helvetica chimica acta》2016,99(4):310-314
Eight heterocycles have been prepared in a one‐pot reaction manner based on the Hantzsch dihydropyridine synthesis. The synthesis afforded seven dihydropyridines (DHP) and one unexpected 1,3‐oxazin‐6‐one. Their structures were confirmed based on NMR spectroscopy and mass spectrometry. The obtained products have been evaluated for their cytotoxicity against eight cancer cell lines and one normal cell line. Two halogenated DHPs ( 7 and 8 ) displayed cytotoxicity toward all the nine tested cancer cell lines with IC50 values from 4.10 to 58.90 μm, while others showed selective activities. DHPs ( 7 and 8 ) bearing a Me group at C(2) and C(6) as well as a halogenated substituent at C(4′) were more antiproliferative than the others. 相似文献
107.
Various ideal periodic isotropic structures of foams (tetrakaidecahedron) with constant ligament cross section are studied. Different strut shapes namely circular, square, diamond, hexagon, star, and their various orientations are modeled using CAD. We performed direct numerical simulations at pore scale, solving Navier–Stokes equation in the fluid space to obtain various flow properties namely permeability and inertia coefficient for all shapes in the porosity range, \(0.60<\varepsilon <0.95\) for wide range of Reynolds numbers, \(10^{-6} . We proposed an analytical model to obtain pressure drop in metallic foams in order to correlate the resulting macroscopic pressure and velocity gradients with the Ergun-like approach. The analytical results are fully compared with the available numerical data, and an excellent agreement is observed. 相似文献
108.
Frederic William Patureau Tatiana Besset Roland Fröhlich Frank Glorius 《Comptes Rendus Chimie》2012,15(11-12):1081-1085
In the last few years, Rh(III)-catalyzed CH functionalizations have made tremendous progress and, consequently, have recently received increasing attention. These CH activation reactions, generally involving a chelate assisting directing group, have been utilized to form valuable heterocycles and to run useful coupling reactions. In this paper, three different transformations are presented and discussed. In order to unequivocally determine the stereochemistry of some of these transformations, crystal structural analysis data are provided. 相似文献
109.
Scalbert J Meunier FC Daniel C Schuurman Y 《Physical chemistry chemical physics : PCCP》2012,14(7):2159-2163
CO(2) is a major contaminant of renewable H(2) derived from biomass fermentation. The effect of the presence of CO(2) on the activity of alumina-supported Pt and Rh catalysts used for the hydrogenation of toluene at 348 K was investigated. The use of operando diffuse reflectance spectroscopy (DRIFTS) was crucial in unravelling the changes in the nature and abundance of species adsorbed at the sample surface and relating those to the changes of catalytic activity. Rhodium supported on alumina was only partly deactivated by the introduction of CO(2) during the hydrogenation of toluene, contrary to the case of Pt/alumina. Rh was only partially covered by carbonyl species derived from CO(2) and it was shown that toluene could successfully compete with some of the linearly adsorbed carbonyls for adsorption. The alumina support stored many CO(2)-derived adsorbates (carbonates, hydrogenocarbonates, carboxylates) that could spill over to the metal and form carbonyl species even after the removal of CO(2) from the feed. 相似文献
110.
Quardokus RC Lu Y Wasio NA Lent CS Justaud F Lapinte C Kandel SA 《Journal of the American Chemical Society》2012,134(3):1710-1714
Scanning tunneling microscopy (STM) is used to study two dinuclear organometallic molecules, meta-Fe2 and para-Fe2, which have identical molecular formulas but differ in the geometry in which the metal centers are linked through a central phenyl ring. Both molecules show symmetric electron density when imaged with STM under ultrahigh-vacuum conditions at 77 K. Chemical oxidation of these molecules results in mixed-valence species, and STM images of mixed-valence meta-Fe2 show pronounced asymmetry in electronic state density, despite the structural symmetry of the molecule. In contrast, images of mixed-valence para-Fe2 show that the electronic state density remains symmetric. Images are compared to constrained density functional (CDFT) calculations and are consistent with full localization of charge for meta-Fe2 on to a single metal center, as compared with charge delocalization over both metal centers for para-Fe2. The conclusion is that electronic coupling between the two metal centers occurs through the bonds of the organic linker, and through-space coupling is less important. In addition, the observation that mixed-valence para-Fe2 is delocalized shows that electron localization in meta-Fe2 is not determined by interactions with the Au(111) substrate or the position of neighboring solvent molecules or counterion species. 相似文献