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Summary A method of calculating the separated flow of a viscous fluid is proposed, which allows to split up properly the boundary condition problem from the viscous phenomena. The theory is developed for the flow past a plate and yields wakes of finite extension having an underpressure which depends directly on the amount of vorticity diffusion and dissipation occurring in the fluid. Application of the method to real flows shows good agreement between the calculated and the measured velocity distributions in front of the plate and in the wake.
Résumé Une méthode de calcul de l'écoulement décollé d'un fluide visqueux est proposée qui permet de séparer clairement le problème aux limites des phénomènes visqueux. La théorie est développée pour l'écoulement autour d'une plaque et donne des sillages de longueur finie ayant une dépression de culot directement dépendante de l'intensité de la diffusion et dissipation de la vorticité se produisant dans le fluide. L'application de la méthode à des écoulements réels montre une bonne concordance entre les répartitions de vitesse calculées et mesurées sur le devant de la plaque et dans le sillage.相似文献
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Chemical Transport in the System Mn? O in Consideration of the Oxygen Coexistence Pressure (I) The chemical transport of the coexistent phases Mn2O3? Mn3O4 and Mn3O4? MnO with Cl2, Br2, I2, HCl, HBr, and HI was analysed thermodynamically and experimentally. The mentioned transport agents are able to transport the following phases: 1 Index (o) bedeutet obere, (u) untere Phasengrenze (index (o) – upper phase boundary, (u) – lower phase boundary). . 相似文献
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Kristina O. Kvashnina Anna Yu. Romanchuk Ivan Pidchenko Lucia Amidani Evgeny Gerber Alexander Trigub Andre Rossberg Stephan Weiss Karin Popa Olaf Walter Roberto Caciuffo Andreas C. Scheinost Sergei M. Butorin Stepan N. Kalmykov 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):18044-18044
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MA Freitas CL Hendrickson AG Marshall 《Rapid communications in mass spectrometry : RCM》1999,13(15):1639-1642
We present a novel approach for the determination of activation energy for the unimolecular dissociation of a large (>50 atoms) ion, based on measurement of the unimolecular dissociation rate constant as a function of continuous-wave CO(2) laser intensity. Following a short ( approximately 1 s) induction period, CO(2) laser irradiation produces an essentially blackbody internal energy distribution, whose 'temperature' varies inversely with laser intensity. The only currently available method for measuring such activation energies is blackbody infrared radiative dissociation (BIRD). Compared with BIRD, FRAGMENT: (a) eliminates the need to heat the surrounding ion trap and vacuum chamber to each of several temperatures (each requiring hours for temperature equilibration); (b) offers a three-fold wider range of effective blackbody temperature; and (c) extends the range of applications to include initially cold ions (e.g., gas-phase H/D exchange). Our FRAGMENT-determined activation energy for dissociation of protonated bradykinin, 1.2 +/- 0.1 eV, agrees within experimental error to the value, 1.3 +/- 0.1 eV, previously reported by Williams et al. from BIRD experiments. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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D. Vulpius G. Geipel L. Baraniak A. Rossberg G. Bernhard 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(3):661-667
Summary The complex formation of uranium(VI) with 4-hydroxy-3-methoxybenzoic acid as well as with benzoic acid and 4-hydroxybenzoic
acid was studied. In aqueous solution weak carboxylic 1 : 1 complexes, are formed in which the carboxyl group is bidentately
coordinated to the metal atom. The logarithmic stability constants of these complexes regarding the reaction of the uranyl
ion with the single charged anion of the respective ligands are 2.78±0.02, 2.68±0.04, and 2.71±0.04 at an ionic strength of
0.1 mol/l (NaClO4) and at 25 °C. Bis(4-hydroxy-3-methoxybenzoato)dioxouranium(VI) was obtained as a crystalline compound if the concentrations
of the starting components for the synthesis are increased. The monoclinic compound has a reflections-rich X-ray powder diffraction
pattern. The lattice constants are a = 13.662(9) ?, b = 21.293(7) ?, c = 11.213(3) ?, b = 107.49(4), and V = 3111(2) ?.3 相似文献
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