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21.
Simultaneous temperature and 2D velocity measurements in a turbulent heated jet using combined laser-induced fluorescence and LDA 总被引:1,自引:0,他引:1
This paper presents an efficient technique for the characterization of thermal transport properties in turbulent flows. The
method is based on the temperature dependence of fluorescence, induced by laser radiation, of an organic dye. The laser-induced
fluorescence technique is combined with 2D laser Doppler anemometry, in order to measure in the same sample volume simultaneously
and instantaneously the temperature and velocity. The technique is demonstrated on a turbulent heated round jet: the mean
and fluctuating dynamic and thermal fields are investigated, and the temperature-velocity cross-correlations are determined
in order to characterize the turbulent diffusivity and the turbulent Prandtl number.
Received: 30 October 1997/Accepted: 14 July 1998 相似文献
22.
Alain Bekaert Pascale Lemoine Jean Daniel Brion Bernard Viossat 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):m76-m77
The title compound, tris[(R)‐2‐hydroxypropanamide‐κ2O,O′]zinc(II) tetrabromozincate, [Zn(C3H7NO2)3][ZnBr4], contains one monomeric six‐coordinate zinc complex cation and one tetrahedral [ZnBr4]2− anion. Both ZnII atoms lie on threefold axes. Coordination in the cation occurs via the amide and hydroxy O atoms [Zn—O = 2.074 (5) and 2.073 (6) Å] and has a distorted octahedral geometry, with cis‐O—Zn—O angles in the range 76.2 (2)–109.2 (2)°. In the crystal structure, the cations and anions are linked by N—H⋯Br and O—H⋯O hydrogen bonds, generating a three‐dimensional network. 相似文献
23.
S. Crunaire J. Tarmoul C. Fittschen A. Tomas B. Lemoine P. Coddeville 《Applied physics. B, Lasers and optics》2006,85(2-3):467-476
The coupling between cavity ring-down spectroscopy (CRDS) and an environmental chamber in the investigation of photo-induced reaction mechanisms is demonstrated for the first time. The development of the CRDS device and the corresponding analytical performances are presented. The first application is devoted to the investigation of the branching ratio of the ?OH radical reaction of CH3C(O)OH and CH3C(O)OD under tropospheric conditions. An environmental chamber coupled to two complementary detection systems is used: gas chromatography with FTIR spectroscopy for quantitative detection of acetic acid; CRDS for quantitative detection of CO2. Investigation of the reaction kinetics of ?OH+CH3C(O)OH gives a rate constant of (6.5±0.5)×10-13 cm3?molecule-1?s-1 (296 K) and shows good agreement with literature data. The product study indicates that the H-abstraction channel from the acid group is the dominant pathway with a branching ratio of (78±13)%, whereas the corresponding D-abstraction channel in the ?OH+CH3C(O)OD reaction represents only (36±7)%. This result could be attributed to a strong kinetic isotope effect. Glyoxylic acid has also been detected for the first time as by-product. These results illustrate the high interest of the CRDS technique in the investigation of atmospheric relevant problems. 相似文献
24.
Mohammad A. Halim Marion Girod Luke MacAleese Jérôme Lemoine Rodolphe Antoine Philippe Dugourd 《Journal of the American Society for Mass Spectrometry》2016,27(9):1435-1442
Herein we report the successful implementation of the consecutive and simultaneous photodissociation with high (213 nm) and low (10.6 μm) energy photons (HiLoPD, high-low photodissociation) on ubiquitin in a quadrupole-Orbitrap mass spectrometer. Absorption of high-energy UV photon is dispersed over the whole protein and stimulates extensive C–Cα backbone fragmentation, whereas low-energy IR photon gradually increases the internal energy and thus preferentially dissociates the most labile amide (C–N) bonds. We noticed that simultaneous irradiation of UV and IR lasers on intact ubiquitin in a single MS/MS experiment provides a rich and well-balanced fragmentation array of a/x, b/y, and z ions. Moreover, secondary fragmentation from a/x and z ions leads to the formation of satellite side-chain ions (d, v, and w) and can help to distinguish isomeric residues in a protein. Implementation of high-low photodissociation in a high-resolution mass spectrometer may offer considerable benefits to promote a comprehensive portrait of protein characterization. 相似文献
25.
Aravind G Klærke B Rajput J Toker Y Andersen LH Bochenkova AV Antoine R Lemoine J Racaud A Dugourd P 《The Journal of chemical physics》2012,136(1):014307
Photodissociation lifetimes and fragment channels of gas-phase, protonated YA(n) (n = 1,2) peptides and their dimers were measured with 266 nm photons. The protonated monomers were found to have a fast dissociation channel with an exponential lifetime of ~200 ns while the protonated dimers show an additional slow dissociation component with a lifetime of ~2 μs. Laser power dependence measurements enabled us to ascribe the fast channel in the monomer and the slow channel in the dimer to a one-photon process, whereas the fast dimer channel is from a two-photon process. The slow (1 photon) dissociation channel in the dimer was found to result in cleavage of the H-bonds after energy transfer through these H-bonds. In general, the dissociation of these protonated peptides is non-prompt and the decay time was found to increase with the size of the peptides. Quantum RRKM calculations of the microcanonical rate constants also confirmed a statistical nature of the photodissociation processes in the dipeptide monomers and dimers. The classical RRKM expression gives a rate constant as an analytical function of the number of active vibrational modes in the system, estimated separately on the basis of the equipartition theorem. It demonstrates encouraging results in predicting fragmentation lifetimes of protonated peptides. Finally, we present the first experimental evidence for a photo-induced conversion of tyrosine-containing peptides into monocyclic aromatic hydrocarbon along with a formamide molecule both found in space. 相似文献
26.
A. Guyot A. Revillon L. David J.P. Lemoine N. Fischer Y. Legrand 《European Polymer Journal》1984,20(8):811-815
Bulk copolymerizations of vinyl chloride (VC) and vinyl carbonate monomers were carried out at 50°. For vinyl-phenyl carbonate (CPV), the reactivity ratios are rCV = 1.6 and rCPV = 0.3. Slightly but regularly crosslinked copolymers are produced using moderate amount of bisvinylcarbonate; the crosslinking efficiency of the second vinyl function of the comonomer is very high, particularly if the two vinyl functions are linked through a flexible aliphatic moiety. Improved creep resistance is given by a small amount of crosslinking. 相似文献
27.
28.
The J = 7/2, 9/2, 11/2, 13/2 and 15/2 Λ doubling main lines of OH in the ν = 1, 2 Π3/2 state have been measured. They are used with the UV and IR data to predict the low J frequencies with an accuracy sufficient for radioastronomical search. 相似文献
29.
30.
The thermal behaviours of dimanganese decacarbonyl and dirhenium decacarbonyl were studied by TG, DTG and DTA. The decomposition products in different media were identified by X ray diffraction. In an inert medium, no important difference is observed between the two compounds. In an oxidizing medium, the identified products at 350? are a mixture of MnO andγ-Mn2O3 for the manganese compound and ReO3 for that of Re. The decomposition temperatures of these metal carbonyls are functions of the studied medium. According to studies of metal-metal bond dissociation energies, Mn2(CO)10 is less stable than Re2(CO)10. 相似文献