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We determine all primitive groups which do not have a regularorbit on the power set of the permutation domain. As a corollary,we also determine all families of orbit equivalent primitivepermutation groups. 1991 Mathematics Subject Classification20B15. 相似文献
3.
Summary Mercury was determined by Zeeman Atomic Absorption Spectrometry after matrix modification of urine and waste water by addition of 0.1M HNO3, 0.05M KBr, and 5l Br2/ml, and after its extraction from sludge, iron sludge and ion exchanger by a mixture containing the same additives. The same samples were also analysed by the cold vapour method after wet oxidation of the samples in closed teflon bombs. The ratio of the corresponding concentrations was 1.21±0.39 (SD) and the concentration range covered 0.1–50000 mg Hg/kg. The analytical powers of both procedures are compared.
Bestimmung von Quecksilber in Schlamm und in für die Reinigung industrieller Abwässer verwendeten Materialien mit der Zeeman-Atomab-sorptions-Spektrometrie nach Matrixmodifizierung durch Kaliumbromid und Brom
Zusammenfassung Quecksilber wurde mit der Zeeman-Atomabsorptions-Spektroskopie in Urin und Abwässern nach einer Matrixmodifizierung durch Zugabe von 0,1M HNO3, 0,05M KBr und 5 l Br2/ml sowie nach seiner Extraktion aus Schlamm, Eisenschlamm und Ionenaustauschern mit einer Mischung der gleichen Zusatzstoffe bestimmt. Die gleichen Proben wurden auch nach der Kalt-Dampf-Methode nach dem Naßaufschluß in geschlossenen Teflonbomben analysiert. Das Verhältnis der betreffenden Konzentrationen betrug 1,21±0,39 (Standardabweichung), wobei der Konzentrationsbereich 0,1–50000 mg Hg/kg umfaßte. Die analytischen Leistungsfähigkeiten der beiden Verfahren wurden verglichen.相似文献
4.
János?W?lfling Angéla?Magyar Gyula?SchneiderEmail author 《Monatshefte für Chemie / Chemical Monthly》2003,134(10):1387-1393
Summary. A new synthetic route was developed for the preparation of trans-3-hydroxy-16,17-seco-pregna-5,17(20)-dien-16-al, using Grob fragmentation as the key step. This seco-steroid contains a formyl group and an unsaturated side-chain in a sterically favourable position, and is therefore a promising starting material for the synthesis of novel condensed steroid heterocycles.Received March 22, 2003; accepted April 22, 2003
Published online September 25, 2003 相似文献
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A large succinic acid (HOOC(CH2)2COOH) matrix containing 7 × 7 × 7 unit cells with guest oligonucleotide AGCAGCT was modeled with molecular dynamics simulation
for infrared matrix-assisted laser desorption ionization. We simulated the laser heating of the succinic acid (this data is
still missing from the literature) with λ=2.94 μm infrared laser pulses and compared it to ultraviolet excitation. We did
this in order to elucidate the cluster formation of succinic acid in the gas phase in itself and around the analyte. At this
wavelength, the laser energy is coupled into the matrix through the OH vibrations of the carboxyl groups. The most pronounced
difference we observed at 1,500 K simulation is that infrared heating generates about 10–15 more succinic acid molecules bound
to the analyte in noncovalent complex form than the ultraviolet mode, which generates about 2 molecules thus bound. We report
energy redistribution within the matrix between the host and guest species as well as other dynamical properties. The parameter
and topology data for succinic acid that we used are reported and ready for use in CHARMM computer code environment for simulation.
Revised: 12 October 2001 / Accepted: 27 February 2002 / Published online: 13 June 2002 相似文献
7.
János Gyimesi Éva Szökő Kálmán Magyar Lajos Barcza 《Journal of inclusion phenomena and macrocyclic chemistry》1996,25(1-3):253-256
Binding constants of the optical isomers of Deprenyl® (selegiline) and its potential metabolites with (2,6-di-O-methyl)--cyclodextrin were determined using electrophoretic mobility data gained from separations performed by capillary electrophoresis, and absorbancies obtained from spectrophotometric experiments. To calculate equilibrium constants l: l complex formation have been assumed. The comparison of the equilibrium constants calculated from different methods shows similar values in their order of magnitude. Their difference may probably be explained by the different media of the measurements. The effect of the structure of compounds on chiral discrimination were also elucidated. 相似文献
8.
Jan Claereboudt Magda Claeys Herman Geise Renaat Gijbels Akos Vertes 《Journal of the American Society for Mass Spectrometry》1993,4(10):798-812
The use of laser microprobe mass spectrometry (LMMS) for the structural characterization of thermolabile quaternary phosphonium salts has been evaluated. A comparison has been made between LM mass spectra obtained by direct analysis of “neat” organic salts and the corresponding “matrix-assisted” LM mass spectra. Main limitations of LMMS for the direct analysis of neat organic salts (i.e., no matrix) result from (1) formation of artifact ions that originate from thermal degradation and surface recombination reactions and (2) poor shot-to-shot reproducibility of the spectra. Dilution of the organic salts in a suitable, UV-absorbing matrix (e.g., nicotinic acid) significantly enhances the quality of the LM mass spectra. Improvements are: (1) an increase of the ion yield of preformed cations, (2) reduction or elimination of thermal decomposition and other deleterious surface reactions, and (3) a much better shot-to-shot spectral reproducibility. An interesting analytical feature is that these LM mass spectra, which contain only a few matrix peaks, can be obtained for subnanogram amounts of sample. The results also show that triphenylphosphonium salts with polycyclic aromatic substituents can be used as “molecular thermometers” to probe both the temperatures experienced by the sample molecules during the laser-induced desorption ionization process and the internal energies of the desorbed ion species. In this way, quaternary phosphonium salts can be used for evaluating whether improvements have been achieved by applying different sample treatments. Comparison of four different matrices (i.e., nicotinic acid, ammonium chloride, glycerol, and 3-nitrobenzylalcohol) indicates that the effectiveness of a matrix to reduce thermal degradation and to decrease the internal energies of the ions depends on the UV-absorption characteristics and the volatilization/sublimation temperature of the matrix material. 相似文献
9.
The sensitivity SA of determination by inductively coupled plasma atomic absorption spectrometry (ICP—AAS) is discussed. All important factors influencing SA are comprised in one single sensitivity formula, which allows an estimate to be made of the correct order of magnitude of SA for both flame—AAS and ICP—AAS measurements. The most important analytical factors are the degree of dissociation and ionization (0≤fC, and fI≤1), the dilution factor fD, which takes into account the dilution of the analysis element A by its transition from the solution to the ICP, and the absorption path length b. Like flame—AAS, an analytical approach using ICP—AAS has high selectivity and makes it possible to carry out determinations without chemical and ionization interferences. This important advantage of ICP—AAS in comparison to flame—AAS is based on the fact that the ideal condition fC→1 and Δf→0 for the analysis and standard solutions can be much more easily realized in the ICP than in flames. Serious disadvantages of an ICP as an atomic reservoir for AAS are the reduced sensitivity and lower detection power compared to flame—AAS. The reduction of SA is caused mainly by the reduction of b/fD by a factor of about 0.1 and to a smaller degree by stronger broadening of the absorption line and the depopulation of the lower energy state of the atom A that absorbs the resonance radiation. The estimated SA value for A = Ag, Al, Ca, Cd, Co, Cr, Cu, Pd and Pt agree with the corresponding experimental values to within a factor of about 3. No experimental values could be obtained for B and Si. An application field of ICP—AAS is the analysis of complex compounds that are difficult to dissociate into atoms using flames. In these determinations, a high sensitivity is generally not needed but a good selectivity is important. Some applications are shown. 相似文献
10.
Dr. Akos Banyasz Dr. Thomas Gustavsson Dr. Delphine Onidas Dr. Pascale Changenet‐Barret Dr. Dimitra Markovitsi Dr. Roberto Improta 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3762-3774
The singlet excited states of adenine oligomers, model systems widely used for the understanding of the interaction of ultraviolet radiation with DNA, are investigated by fluorescence spectroscopy and time‐dependent (TD) DFT calculations. Fluorescence decays, fluorescence anisotropy decays, and time‐resolved fluorescence spectra are recorded from the femtosecond to the nanosecond timescales for single strand (dA)20 in aqueous solution. These experimental observations and, in particular, the comparison of the fluorescence behavior upon UVC and UVA excitation allow the identification of various types of electronic transitions with different energy and polarization. Calculations performed for up to five stacked 9‐methyladenines, taking into account the solvent, show that different excited states are responsible for the absorption in the UVC and UVA spectral domains. Independently of the number of bases, bright excitons may evolve toward two types of excited dimers having π–π* or charge‐transfer character, each one distinguished by its own geometry and spectroscopic signature. According to the picture arising from the joint experimental and theoretical investigation, UVC‐induced fluorescence contains contribution from 1) exciton states with a different degree of localization, decaying within a few ps, 2) “neutral” excited dimers decaying on the sub‐nanosecond timescale, being the dominant species, and 3) charge‐transfer states decaying on the nanosecond timescale. The majority of the photons emitted upon UVA excitation are related to charge‐transfer states. 相似文献