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101.
Meyer JC Paillet M Michel T Moréac A Neumann A Duesberg GS Roth S Sauvajol JL 《Physical review letters》2005,95(21):217401
Using electron diffraction on freestanding single-walled carbon nanotubes, we have determined the structural indices (n,m) of tubes in the diameter range from 1.4 to 3 nm. On the same freestanding tubes, we have recorded Raman spectra of the tangential modes and the radial breathing mode. For the smaller diameters (1.4-1.7 nm), these measurements confirm previously established radial breathing mode frequency versus diameter relations and would be consistent with the theoretically predicted proportionality to the inverse diameter. However, for extending the relation to larger diameters, either a yet unexplained environmental constant has to be assumed, or the linear relation has to be abandoned. 相似文献
102.
Zioutas K Andriamonje S Arsov V Aune S Autiero D Avignone FT Barth K Belov A Beltrán B Bräuninger H Carmona JM Cebrián S Chesi E Collar JI Creswick R Dafni T Davenport M Di Lella L Eleftheriadis C Englhauser J Fanourakis G Farach H Ferrer E Fischer H Franz J Friedrich P Geralis T Giomataris I Gninenko S Goloubev N Hasinoff MD Heinsius FH Hoffmann DH Irastorza IG Jacoby J Kang D Königsmann K Kotthaus R Krcmar M Kousouris K Kuster M Lakić B Lasseur C Liolios A Ljubicić A Lutz G Luzón G Miller DW 《Physical review letters》2005,94(12):121301
Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses. 相似文献
103.
Morán MC Pinazo A Clapés P Infante MR Pons R 《The journal of physical chemistry. B》2005,109(48):22899-22908
Monoacylglycerol amino acid conjugates constitute a novel class of specific biocompatible surfactants that can be considered analogues to partial glycerides and lysophospholipids. They consist of one aliphatic chain and one polar head, i.e., the amino acid, linked through a glycerol moiety. In a previous work, we synthesized monolauroylated amino acid glyceride conjugates, 1-O-lauroyl-rac-glycero-3-O-(N(alpha)-acetyl-L-amino acid), changing the amino acid headgroup systematically: arginine (compound 2), aspartic acid (compound 3), glutamic acid (compound 4), asparagine (compound 5), glutamine (compound 6), and tyrosine (compound 7), to elucidate the structure-properties relationship governing the occurrence of their polymorphism. The thermotropism of the new compounds was measured with polarizing light microscopy, differential scanning calorimetry, and X-ray diffraction and compared with the classical monoglyceride rac-1-lauroylglycerol (compound 1). The experiments were performed for a sequence of heating, cooling, and reheating scans. The results showed that compounds 1-6 exhibit a thermotropic smectic phase. As a consequence, the substitution of the polar head did not engender any curvature into the system, which might lead to the formation of cubic or columnar phases. Interestingly, liquid crystalline phases were not found in the case of compound 7. Small-angle X-ray diffraction data in the gel phase revealed that the substitution of the polar head by the different amino acid structures did not modify significantly the lamellar repeat distance relative to that of the reference one. The observed area per molecule, however, was larger for the new compounds. Consequently, interdigitation was promoted in compounds 2-7. The diffraction patterns were analyzed in terms of electron density profiles, using a modified Caillé theory plus a Gaussian electron density representation (MCG method) on X-ray diffraction data. 相似文献
104.
Moisés Morán 《Transition Metal Chemistry》1981,6(3):173-175
Summary -Cp2Cr reacts with PX3 (X = Cl, Br or I) to give monocyclopentadienylchromium(III) derivatives -CpCrX2 (X = Cl, Br or I), while oxidative additions of IBr and ICl to -Cp2Cr give the corresponding mixed halogenated derivatives, -Cp2CrIX (X = Cl or Br). All products have been characterized by elemental analyses, magnetic moment measurements and by i.r. and e.p.r. spectra. 相似文献
105.
Degrees of Freedom of a Time Series 总被引:4,自引:0,他引:4
We give a formal proof that if f is a smooth dynamics on a d-dimensional smooth manifold and is an ergodic and exact dimensional measure with Hausdorff dimension dim >d–1, then the number d of degrees of freedom of the dynamics can be recovered from the observation of an orbit. We implement, with this purpose, an algorithm based on the analysis of the microstructure of . We show how a correct estimation of d permits the computation of the Liapunov spectrum with a high accuracy avoiding the issue of the spurious exponents. 相似文献
106.
Ganguly Soumya Gaonkar Raghuvir H. Sinha Samarendu Gupta Amit Chattopadhyay Dipankar Chattopadhyay Sankha Sachdeva Satbir S. Ganguly Shantanu Debnath Mita C. 《Journal of nanoparticle research》2016,18(7):1-21
Journal of Nanoparticle Research - This paper investigates the global nanotechnology and nanoscience (NN) indicators in a developmental context, during three 5-year periods from 2000 to 2014.... 相似文献
107.
Effect of oxidant on electronic transport in polypyrrole nanotubes synthesized in the presence of methyl orange
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Martin Varga Jitka Kopecká Zuzana Morávková Ivo Křivka Miroslava Trchová Jaroslav Stejskal Jan Prokeš 《Journal of Polymer Science.Polymer Physics》2015,53(16):1147-1159
Polypyrrole nanotubes with diameter 60–400 nm are synthesized with methyl orange as template and various oxidants, iron(III) chloride hexahydrate, iron(III) sulfate hydrate, and ammonium peroxydisulfate. The highest electrical conductivity of compressed pellets, 66 S cm?1, is found for iron(III) chloride. Regions with 3D variable range hopping in series with ordered regions near metal–insulator transition govern the charge transport. Other oxidants and globular morphology provide less conducting samples, <10 S cm?1. The transport mechanism is identified with the heterogeneous model of tunneling between (bi)polaronic clusters with parallel contribution of Arrhenius‐like activated conductivity. The results of conductivity are correlated with the protonation level reflected in the infrared spectra and with the ratio of bipolaron/polaron bands revealed by Raman spectroscopy. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1147–1159 相似文献
108.
109.
Exploiting Free‐Energy Minima to Design Novel EphA2 Protein–Protein Antagonists: From Simulation to Experiment and Return
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Dr. Matteo Incerti Dr. Daniele Pala Dr. Carmine Giorgio Dr. Jlenia Brunetti Prof. Luisa Bracci Prof. Paola Vicini Prof. Elisabetta Barocelli Dr. Luigi Capoferri Prof. Silvia Rivara Prof. Massimiliano Tognolini Prof. Marco Mor Prof. Alessio Lodola 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8048-8052
The free‐energy surface (FES) of protein–ligand binding contains information useful for drug design. Here we show how to exploit a free‐energy minimum of a protein‐ligand complex identified by metadynamics simulations to design a new EphA2 antagonist with improved inhibitory potency. 相似文献
110.