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1.
Dore Augusto Clemente Armando Marzotto Giovanni Valle 《Journal of chemical crystallography》1988,18(2):147-156
The crystal and molecular structure of thiamine monochloride (C12H17N4OSCl) was determined by X-ray diffraction and refined to a finalR value of 0.042. The compound crystallizes in the monoclinic system, space groupP21/a, with cell constantsa=18.929(4),b=11.663(2),c=6.376(2) Å and=96.72(8)°. The thiamine molecule is anhydrous and unprotonated, and the torsion angles at the methylene carbon show that it possesses anF conformation. The dihedral angle value of 84.16(6)° between thiazolium and pyrimidine rings is in the normal range found for the thiamine withF conformation, protonated or not, hydrated or not. Thiamine therefore has the same conformation notwithstanding protonation or hydration, with the rings similarly oriented in all the crystal structures containing thiamine. 相似文献
2.
Antimony(III) can be extracted rapidly and quantitatively into benzene from a 10 M H2SO4–0.03 M HBr system. The extracted antimony bromide has an antimony to bromine ratio of 1:3. Under the above optimum conditions for extraction of antimony, the behaviour of 35 other elements was studied; As3+, Ge4+, Se4+, and Sn2+ were extracted almost quantitatively, and the percentage extraction of Hg2+, Bi3+, and Te4+ was 74.1%, 10% and 5.5% respectively. The extraction of the elements into benzene from a 5 M H2SO4–0.01 M KI system was also investigated, A comparison of the two systems is given. 相似文献
3.
Alessio Melli Simone Potenti Dr. Mattia Melosso Dr. Sven Herbers Dr. Lorenzo Spada Dr. Andrea Gualandi Kevin G. Lengsfeld Prof. Luca Dore Philipp Buschmann Prof. Pier Giorgio Cozzi Prof. Jens-Uwe Grabow Prof. Vincenzo Barone Prof. Cristina Puzzarini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):15016-15022
Phenylmethanimine is an aromatic imine with a twofold relevance in chemistry: organic synthesis and astrochemistry. To tackle both aspects, a multidisciplinary strategy has been exploited and a new, easily accessible synthetic approach to generate stable imine-intermediates in the gas phase and in solution has been introduced. The combination of this formation pathway, based on the thermal decomposition of hydrobenzamide, with a state-of-the-art computational characterization of phenylmethanimine laid the foundation for its first laboratory observation by means of rotational electric resonance spectroscopy. Both E and Z isomers have been accurately characterized, thus providing a reliable basis to guide future astronomical observations. A further characterization has been carried out by nuclear magnetic resonance spectroscopy, showing the feasibility of this synthetic approach in solution. The temperature dependence as well as possible mechanisms of the thermolysis process have been examined. 相似文献
4.
The hyperfine structure in the ground-state rotational spectrum of methanimine was studied in the frequency range of 64-172 GHz by means of the Lamb-dip technique. This allowed to resolve, in some hyperfine components due to the 14N nucleus, doublets separated by only some tenth of kHz. We explain the splittings as due to magnetic interactions of the three protons with their molecular environment. The analysis of the experimental spectrum has been guided by quantum-chemical calculations of the hyperfine parameters. 相似文献
5.
Aliu E Andringa S Aoki S Argyriades J Asakura K Ashie R Berns H Bhang H Blondel A Borghi S Bouchez J Burguet-Castell J Casper D Cavata C Cervera A Cho KO Choi JH Dore U Espinal X Fechner M Fernandez E Fukuda Y Gomez-Cadenas J Gran R Hara T Hasegawa M Hasegawa T Hayashi K Hayato Y Helmer RL Hill J Hiraide K Hosaka J Ichikawa AK Iinuma M Ikeda A Inagaki T Ishida T Ishihara K Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jeon EJ Jeong IS Joo K Jover G Jung CK Kajita T Kameda J Kaneyuki K Kato I 《Physical review letters》2005,94(8):081802
We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma). 相似文献
6.
The rotational spectra of the unstable HCCCP molecule have been investigated in the millimeter-wave region for the main excited vibrational states which lie below 1000 cm(-1), namely nu(4) (C&bond;C stretch), nu(5) (HCC bend), nu(6) (CCC bend), nu(7) (CCP bend), 2nu(6), 2nu(7), 3nu(7), 4nu(7), nu(5) + nu(7), and nu(6) + nu(7). l-type resonance effects have been taken into account in the analysis of the spectra, so that the values of the anharmonicity constants x(L(66)), x(L(77)), x(L(57)), and x(L(67)) could be determined. The anharmonic interactions which couple the nu(4) state with nu(6) + nu(7), 2nu(6), and 4nu(7) have been also considered, yielding the unperturbed value of the alpha(4) vibration-rotation coupling constant. Copyright 2001 Academic Press. 相似文献
7.
8.
J. Dorenbosch F. Udo J. V. Allaby U. Amaldi G. Barbiellini M. Baubillier F. Bergsma A. Capone W. Flegel F. Grancagnolo M. Jonker L. Lanceri M. Metcalf C. Nieuwenhuis J. Panman R. Plunkett C. Santoni K. Winter I. Abt F. W. Büsser H. Daumann P. D. Gall T. Hebbeker F. Niebergall P. Stähelin P. Gorbunov E. Grigoriev V. Kaftanov V. Khovansky A. Rosanov A. Baroncelli L. Barone B. Borgia C. Bosio M. Diemoz U. Dore F. Ferroni E. Longo L. Luminari P. Monacelli S. Morganti F. de Notaristefani L. Tortora V. Valente CHARM Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,41(4):567-589
A determination of sin2 θ w based on measurements of elastic scattering of muon-neutrinos and muon-anti-neutrinos on atomic electrons is described. These purely leptonic processes were studied using the CHARM calorimeter exposed to neutrino and antineutrino wide-band beams at the CERN super proton synchrotron. A total of 83±16 neutrino-electron and 112±21 antineutrino-electron events have been detected. From the measurement of the ratio of muon-neutrino and muon-antineutrino cross-sections a value of sin2 θ w =0.211±0.037 was obtained. 相似文献
9.
On the closedness of the sum of two closed operators 总被引:16,自引:0,他引:16
10.
Sol-gel silicas with nominal pore diameters ranging from 25A to 500A were studied by NMR cryoporometry, and by neutron diffraction and small angle scattering from dry silicas over the Q range 8. 10(-4)A(-1) < or = Q < or = 17A(-1). Density and imbibation experiments were also performed. Geometric models of porous systems were constructed and were studied by both analytic techniques and Monte-Carlo integration. These models, combined with the information from the above measurements, enabled the calculation of the fully density corrected solid-solid density correlation functions G(r) for the sol-gel silicas, deduction of the (voidless) silica matrix density, measurement of the silica fraction in the grain and of the packing fraction of the silica grains and an estimation of the water equivalent residual hydrogen on the dried silica surface. In addition, the pore diameter D, pore diameter to lattice spacing ratio D/a, and pore and lattice variance sigma could also be measured. While the NMR cryoporometry pore diameter measurements for the sol-gel silicas show excellent co-linearity with the nominal pore diameters as measured by gas adsorption, and the calculated pore diameters from the measured neutron scattering show surprisingly good agreement with these measurements at large pore diameters, there is a divergence between the calibrations for pore diameters below about 100A. 相似文献