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排序方式: 共有460条查询结果,搜索用时 15 毫秒
91.
Koichi Todoroki Maurizio Corradini Ryugo S. Hayano Takumi Kobayashi Marco Leali Evandro Lodi Rizzini Valerio Mascagna Anna Soter Luca Venturelli Nicola Zurlo Masaki Hori 《Hyperfine Interactions》2012,213(1-3):199-204
The ASACUSA (the Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration is planning to measure the cross sections of antiproton annihilations at kinetic energy 100 keV on targets of various mass numbers (C,?Ni, Sn, and Pt) using the Antiproton Decelerator (AD) of CERN. No previous measurement exists in this region where the A-dependence of the cross section is expected to deviate from the A $^{\frac{2}{3}}$ (Batty et al, Nucl Phys A 689:721, 2001) as reported by the Obelix collaboration. A beam profile monitor based on secondary electron emission with a grid of electrode pads fabricated on an FR4-type glass-epoxy circuit board was developed for this measurement. The advantage of this kind of detector is that it is simple, lightweight, and low cost. It was used to measure the spatial profile of 100-ns-long beam pulses containing > 6 × 104 antiprotons with an active area of 40?mm?× 40 mm and a spatial resolution of 4 mm. 相似文献
92.
Marcos V. dos S. Rezende Paulo J.R. Montes Mário E.G. Valerio 《Journal of luminescence》2012,132(5):1106-1111
The luminescence properties of Ce3+ in BaAl2O4 are reported. The results of simultaneous measurements of XEOL and XAS in the X-ray energy range that includes the Ba LII,III-edges and Ce LIII edge are shown. The XEOL yield increases as the energy of the photons increases. The radioluminescence spectra, taken from 200 to 1100 nm, showed broad emission bands corresponding to 5d1→2F5/2, 2F7/2 transitions of Ce3+ when incorporated into two nonequivalent Ba sites. The lifetime of the light emission was also measured using the single bunch operation mode at the Brazilian National Synchrotron Laboratory (LNLS), and BaAl2O4:Ce3+ showed single exponential decay time component of about 44.3 ns. 相似文献
93.
The main results of the extreme value theory developed for the investigation of the observables of dynamical systems rely,
up to now, on the block maxima approach. In this framework, extremes are identified with the block maxima of the time series
of the chosen observable, in the limit of infinitely long blocks. It has been proved that, assuming suitable mixing conditions
for the underlying dynamical systems, the extremes of a specific class of observables are distributed according to the so
called Generalised Extreme Value (GEV) distribution. Direct calculations show that in the case of quasi-periodic dynamics
the block maxima are not distributed according to the GEV distribution. In this paper we show that considering the exceedances
over a given threshold instead of the block-maxima approach it is possible to obtain a Generalised Pareto Distribution also
for extremes computed in systems which do not satisfy mixing conditions. Requiring that the invariant measure locally scales
with a well defined exponent—the local dimension—, we show that the limiting distribution for the exceedances of the observables
previously studied with the block maxima approach is a Generalised Pareto distribution where the parameters depend only on
the local dimensions and the values of the threshold but not on the number of observations considered. We also provide connections
with the results obtained with the block maxima approach. In order to provide further support to our findings, we present
the results of numerical experiments carried out considering the well-known Chirikov standard map. 相似文献
94.
Gialiana Biagi Irene Giorgi Oreste Livi Valerio Scartoni Silvia Velo Pier Luigi Barili 《Journal of heterocyclic chemistry》1996,33(6):1847-1853
A new 4-(benzotriazol-1-yl)-1,2,3-triazole structure was obtained by the diazotization reaction of either of 1-(2-aminophenyl)-4-carboxamido-5-amino-1H-1,2,3-triazole ( 1c ) or of the corresponding Dimroth isomer 1d . It underwent some common reactions to evaluate its chemical behaviour and structure. An analogous reaction sequence was carried out from the 2-nitro-4-methylphenyl azide, to assign the structure to the nitro derivatives prepared. The structure of the new compounds prepared was confirmed by chemical and spectroscopic methods. 相似文献
95.
Valerio Pedro Prates Frias Jesus Maria Cren Erika Cristina 《Journal of Thermal Analysis and Calorimetry》2021,143(4):2983-2994
Journal of Thermal Analysis and Calorimetry - In the present study, the kinetics of β-carotene and β-cryptoxanthin degradation were investigated in edible oil mechanically extracted from... 相似文献
96.
97.
Silvia Coniglio Sandro Colagioia Fabrizio D'Alessandro Valerio D'Elia Valerie Orlando 《Tetrahedron letters》2004,45(28):5375-5378
A new, simple and efficient procedure for the preparation of secondary amides through internal condensation of acylmethanesulfonamides ammonium salts is described. The selective acylation of mixed primary-secondary amines could be an attractive application of the new method. 相似文献
98.
Supported by Comité Conjunto Hispano-Norteamericano and by NSF Grant #8120790 相似文献
99.
3-Benzyl-3-hydroxy-2-phenylphthalimidine ( 1 ) and 3-anilino-3-benzyl-2-phenylphthalimidine ( 2 ), the unusual adduct, are obtained from the title compounds. 3-Alkoxy-3-benzyl-2-phenylphthalimidines 3 are synthesized. The behaviour of 1 , 3-benzylidene-2-phenylphthalimidines ( 4 and 5 ), 3-(α-bromobenzylidene)-2-phenylphthalimidines ( 6 and 7 ) with respect to bases and the preparation of the open tautomer 13 of 1 and its hydrochloride are described. A hypothetical mechanism about the formation of 1 and 2 is suggested. 相似文献
100.
Stefaan Cottenier Veerle Vanhoof Doru Torumba Valerio Bellini Mehmet Çakmak Michel Rots 《Hyperfine Interactions》2004,158(1-4):9-18
For some years already, ab initio calculations based on Density Functional Theory (DFT) belong to the toolbox of the field of hyperfine interaction studies.
In this paper, the standard ab initio approach is schematically sketched. New features, methods and possibilities that broke through during the past few years
are listed, and their relation to the standard approach is explained. All this is illustrated by some highlights of recent
ab initio work done by the Nuclear Condensed Matter Group at the K.U.Leuven. 相似文献