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41.
B. Pilawa I. Keilhauer R. Bofinger D. Marinov S. Knorr A. Grupp 《Applied magnetic resonance》2001,21(3-4):527-534
The eigenstates of the antiferromagnetic spin cluster Fe6(tea)6 are studied by electron paramagnetic resonance spectroscopy at 9.5 and 94 GHz in order to characterize the interactions which are important for the magnetic properties of the molecule. Experimental results could be obtained for the first excited spin states withS= 1, 2, 3 and 4. This enables a very accurate and detailed analysis of the intramolecular interactions. It turns out that the magnetic properties of Fe6(tea)6 are determined by the isotropic exchange (J/kB = ?31.5 K), the ligand-field interaction of the FeIII ions and the dipolar interaction. Other kinds of anisotropic interactions are of minor importance. 相似文献
42.
Abstract A radial hydrodynamic flow in the nematic phase of free, suspended cylindrical films of 4-n-heptyl- and decyloxybenzoic acid and in 4,4′-di-n-heptyl-oxyazoxybenzene has been observed. The flow starts about 7°C before the phase transition into the smectic C phase. Under the same experimental conditions such a hydrodynamic flow is not established in free nematic films of 4-n-heptyl-and octyloxy-4′-cyanobiphenyl, 4,4′-dimethoxyazoxybenzene and N-(4-ethoxybenzylidene)-4′-n-butylaniline after the completion of the transition from the isotropic liquid to the nematic phase. The observed hydrodynamic flow is explained by a non-linear temperature dependence of the surface tension. 相似文献
43.
Investigation and optimisation of a multipass resonant photoacoustic cell at high absorption levels 总被引:1,自引:0,他引:1
J.M. Rey D. Marinov D.E. Vogler M.W. Sigrist 《Applied physics. B, Lasers and optics》2005,80(2):261-266
A theoretical and experimental investigation of photoacoustic (PA) signals in a resonant multipass PA cell with high background absorption (up to 29 m-1) is presented. An analogous electric transmission line model including discontinuity inductances at cross section changes was used to model the first longitudinal acoustic mode of the multipass PA cell equipped with two buffer volumes. This model was validated with experimentally obtained results and used to predict the behaviour of the PA cell for different multipass arrangements and different buffer volume diameters. The highest PA signal is obtained for high pass number and large buffer radius. Increasing the absorption coefficient of the medium enhances the PA signal until a maximum is reached, leading to a minimum for the PA signal sensitivity. For a given background absorption, the number of passes required to maximise the sensitivity depends on the absorption coefficient. The model allows the determination of the best-suited number of passes for a given absorption coefficient and cell geometry. PACS 82.80.Kd; 42.62.Fi; 82.80.Gk 相似文献
44.
T. Lund R. Brandt D. Molzahn G. Tress P. Vater A. Marinov 《Zeitschrift für Physik A Hadrons and Nuclei》1981,300(4):285-288
In this paper we describe an attempt to isolate superheavy elements from Atlantis II hot brine deposits. Volatile, sulfidic elements (Cd, Pb) were isolated and investigated for spontaneous fission events with a mica-plastic solid state track detector sandwich. During nearly two years exposure time no spontaneous fission activity was observed. The upper limit for the concentration of superheavy elements (following this chemistry) in the Atlantis II-material is found to be 1.4·10?14g/g. This limit is more than one order of magnitude lower than the concentration of a spontaneous fission activity in material from the Cheleken hot brine, as observed by Flerov and coworkers. 相似文献
45.
L. Lazarov M.-F. Simeonov S. P. Marinov 《Fresenius' Journal of Analytical Chemistry》1984,319(5):552-555
Summary A method is presented for derivation of a series of structural parameters describing the average molecule of soluble butylated coal. It is based on 1H and 13C NMR spectral data, molecular mass measurement and ultimate analysis. Average structural models of coals can be constructed in this way.
Strukturanalyse von alkylierter Kohle mit Hilfe der 1H- und 13C-NMR-Spektroskopie
Zusammenfassung Ein Verfahren wird vorgestellt zur Ableitung einer Reihe von Strukturparametern, die das Durchschnittsmolekül von löslicher butylierter Kohle beschreiben können. Es beruht auf 1H- und 13C-NMR-Spektraldaten, Messungen der Molekülmasse sowie der Elementaranalyse. Durchschnittliche Strukturmodelle von Kohlen können dadurch erstellt werden.相似文献
46.
S. Marinov 《Czechoslovak Journal of Physics》1974,24(9):965-970
Performing the so-called by us “coupled-mirrors” experiment, we have established that velocity of light measured along a given track on the earth's surface is different during the different hours of the day. 相似文献
47.
Marinova P. Marinov M. Kazakova M. Feodorova Y. Blazheva D. Slavchev A. Sbirkova-Dimitrova H. Sarafian V. Stoyanov N. 《Russian Journal of General Chemistry》2021,91(5):939-946
Russian Journal of General Chemistry - The presented study is devoted to the structural and biological properties of four derivatives of fluorenylspirohydantoin based on experimental data. The... 相似文献
48.
Enchev Venelin Markova Nadezhda Marinov Marin Stoyanov Neyko Rogojerov Marin Ugrinov Angel Wawer Iwona Pisklak Dariusz Maciej 《Structural chemistry》2017,28(3):757-772
Structural Chemistry - The synthesis and structure elucidation of two new compounds, 2-(methylthio)-1,3-diazaspiro[4.4]non-2-ene-4-one (1) and 2-(methylthio)-1,3-diazaspiro[4.4]non-2-ene-4-thione... 相似文献
49.
Penchev PN Stoyanov NM Marinov MN 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(2):559-565
Complete assignments of the 1H and 13C NMR chemical shifts for 3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one were done by means of one- and two-dimensional NMR techniques, including 1H-(1)H COSY, HMQC and HMBC spectra. Ab initio quantum chemistry calculations and a shift prediction by an incremental method provided values close to the proposed assignments. All mid-IR spectral bands are given as reference data. The DRIFT FTIR, ATR FTIR and Raman spectra are given as a Supplementary data in JCAMP-DX format, version 4.24. In addition, a method of compound's synthesis, that has the product yield higher as compared to already known data in the literature, is given. 相似文献
50.