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821.
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823.
Edilene Delphino Rodrigues Denise Brentan da Silva Dionéia Camilo Rodrigues de Oliveira Gil Valdo José da Silva 《Magnetic resonance in chemistry : MRC》2009,47(12):1095-1100
2D DOSY 1H NMR has proved to be a useful technique in the identification of the molecular skeleton of the four major compounds of ethyl acetate extract of aerial parts of Bidens sulphurea (Asteraceae). The combination of this technique with HPLC, mass spectrometry and other NMR techniques enabled the identification of four flavonoid glycosides: quercetin‐3‐O‐β‐D ‐galactopyranoside, quercetin‐3‐O‐β‐D ‐glycopyranoside, quercetin‐3‐O‐α‐L ‐arabinofuranoside and quercetin‐3‐O‐β‐D ‐rhamnopyranoside. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
824.
An effective procedure for deciding permutativeness of one-directional cellular automata on the one-sided full shift is presented. It is then implemented in C++, and used to test permutativeness of elementary cellular automata (those of radius 3). 相似文献
825.
R. Navarro M.P. González I. Saucedo M. Avila P. Prádanos F. Martínez A. Martín A. Hernández 《Journal of membrane science》2008
In order to improve the performance of a nanofiltration membrane (DS5 DL from Osmonics®) several pre-treatments have been tested. Specifically, the membrane has been immersed, for different times, in an aqueous solution of HF or H3PO4, or of a mixture of both these acids. The chemical and charge properties of the membranes, both pre-treated and untreated, have been studied. 相似文献
826.
Luben Cabezas-Gómez Renato César da Silva Hélio Aparecido Navarro Fernando Eduardo Milioli 《Applied Mathematical Modelling》2008
A methodology of identification and characterization of coherent structures mostly known as clusters is applied to hydrodynamic results of numerical simulation generated for the riser of a circulating fluidized bed. The numerical simulation is performed using the MICEFLOW code, which includes the two-fluids IIT’s hydrodynamic model B. The methodology for cluster characterization that is used is based in the determination of four characteristics, related to average life time, average volumetric fraction of solid, existing time fraction and frequency of occurrence. The identification of clusters is performed by applying a criterion related to the time average value of the volumetric solid fraction. A qualitative rather than quantitative analysis is performed mainly owing to the unavailability of operational data used in the considered experiments. Concerning qualitative analysis, the simulation results are in good agreement with literature. Some quantitative comparisons between predictions and experiment were also presented to emphasize the capability of the modeling procedure regarding the analysis of macroscopic scale coherent structures. 相似文献
827.
We compute all 2-covariant tensors naturally constructed from a semi-Riemannian metric which are divergence-free and have weight greater than −2. 相似文献
828.
Integration of vector-valued functions is seldom appreciated because of its abstract nature. In this paper, we give a real-valued representation of the Bochner integral of a function with values in an Orlicz space. This is given in the first theorem on the necessary condition for Bochner integrability of such a function. The second theorem gives sufficient conditions for Bochner integrability.AMS Subject Classification (1991) 28Supported by a grant from the Natural Science Research Institute, University of the Philippines, Diliman, Q.C. 1101, Quezon City, Philippines. 相似文献
829.
Reviriego F Rodríguez-Franco MI Navarro P García-España E Liu-Gonzalez M Verdejo B Domènech A 《Journal of the American Chemical Society》2006,128(51):16458-16459
The sodium salt of the diethyl 1H-pyrazole-3,5-dicarboxylate (2) of amphiphilic character is able to interact with (+)-amphetamine, (+)-methamphetamine, and dopamine, yielding stable complexes. Crystal structure of 2 with (+)-amphetamine leads to a very nice double helical supramolecular structure. 相似文献
830.
Masciocchi N Galli S Sironi A Cariati E Galindo MA Barea E Romero MA Salas JM Navarro JA Santoyo-Gonzalez F 《Inorganic chemistry》2006,45(19):7612-7620
Thermally robust materials of the M(5-X-pyrimidin-2-olate)2 type [M = Co, X = Cl (1(Cl)), X = Br (1(Br)), X = I (1(I)); M = Zn, X = Cl (2(Cl)), X = Br (2(Br)), X = I (2(I))] have been synthesized. Their X-ray powder diffraction structural characterization has revealed that they crystallize as I2d diamondoid frameworks, isomorphous to those of the pristine [M(pyrimidin-2-olate)2]n analogues (1(H), M = Co; 2(H), M = Zn). The magnetic measurements of the 1(X) series at magnetic fields of 100, 300, and 5000 Oe reveal a weak ferromagnetic ordering taking place below the Néel temperature (T(N) approximately 20 K), arising from spin canting phenomena of the antiferromagnetically coupled cobalt centers. Moreover, magnetic hysteresis studies carried out on the 1(X) series at 2 K reveal a strong dependence of both the coercive field H(coer) (2500, 1000, 775, and 500 Oe for 1(Br), 1(Cl), 1(I), and 1(H), respectively) and the remnant magnetization M(rem) (0.0501 mu(B) for 1(Br) and 1(Cl), 0.0457 mu(B) for 1(I), and 0.0358 mu(B) for 1(H)) on the 5-substituent of the pyrimidin-2-olates. The molecular alloys [Co(5-Y-pyrimidin-2-olate)2] (Y = Cl/Br, 1(Cl/Br)) and [Co(5-Y'-pyrimidin-2-olate)2] (Y' = Br/I, 1(Br/I)) have also been prepared and characterized, proving that they have intermediate properties. These materials combine interesting functional properties, such as chemical inertness, magnetism, photoluminescence, and (although weak) SHG activity. 相似文献