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31.
We are proposing for the first time the use of a Nafion/multi-walled carbon nanotubes dispersion deposited on glassy carbon electrodes (GCE) as a new platform for developing enzymatic biosensors based on the self-assembling of a chitosan derivative and different oxidases. The electrodes are obtained by deposition of a layer of Nafion/multi-wall carbon nanotubes dispersion on glassy carbon electrodes, followed by the adsorption of a chitosan derivative as polycation and glucose oxidase, l-aminoacid oxidase or polyphenol oxidase, as polyanions and biorecognition elements. The optimum configuration for glucose biosensors has allowed a highly sensitive (sensitivity = (0.28 ± 0.02) μA mM−1, r = 0.997), fast (4 s in reaching the maximum response), and highly selective (0% interference of ascorbic acid and uric acid at maximum physiological levels) glucose quantification at 0.700 V with detection and quantification limits of 0.035 and 0.107 mM, respectively. The repetitivity for 10 measurements was 5.5%, while the reproducibility was 8.4% for eight electrodes. The potentiality of the new platform was clearly demonstrated by using the carbon nanotubes/Nafion layer as a platform for the self-assembling of l-aminoacid oxidase and polyphenol oxidase. Therefore, the platform we are proposing here, that combines the advantages of nanostructured materials with those of the layer-by-layer self-assembling of polyelectrolytes, opens the doors to new and exciting possibilities for the development of enzymatic and affinity biosensors using different transdution modes. 相似文献
32.
A Bayesian statistical approach is introduced to assess experimental data from the analyses of radionuclide activity concentration in environmental samples (low activities). A theoretical model has been developed that allows the use of known prior information about the value of the measurand (activity), together with the experimental value determined through the measurement. The model has been applied to data of the Inter-laboratory Proficiency Test organised periodically among Spanish environmental radioactivity laboratories that are producing the radiochemical results for the Spanish radioactive monitoring network. A global improvement of laboratories performance is produced when this prior information is taken into account. The prior information used in this methodology is an interval within which the activity is known to be contained, but it could be extended to any other experimental quantity with a different type of prior information available. 相似文献
33.
Juan Pablo Navarrete Waldemar Barrera 《Bulletin of the Brazilian Mathematical Society》2009,40(1):99-106
In this paper, we prove following: If G ⊂ PU (2, 1) is an infinite, discrete group, acting on Pℂ2 without complex invariant lines, then the component containing ℍPℂ2 of the domain of discontinuity Ω(G) = PPℂ2∖ Λ (G), according to Kulkarni, is G-invariant complete Kobayashi hyperbolic.
The authors were supported by the Universidad Autónoma de Yucatán and the Universidad Nacional Autónoma de México. 相似文献
34.
Ericsson D. Coy‐Barrera Luis E. Cuca‐Surez Michael Sefkow Uwe Schilde 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(8):o320-o322
The structure of naturally‐occurring cinerin C [systematic name: (7S,8R,3′R,4′S,5′R)‐Δ8′‐4′‐hydroxy‐5,5′,3′‐trimethoxy‐3,4‐methylenedioxy‐2′,3′,4′,5′‐tetrahydro‐2′‐oxo‐7.3′,8.5′‐neolignan], isolated from the ethanol extract of leaves of Pleurothyrium cinereum (Lauraceae), has previously been established by NMR and HRMS spectroscopy, and its absolute configuration established by circular dichroism measurements. For the first time, its crystal strucure has now been established by single‐crystal X‐ray analysis, as the monohydrate, C22H26O7·H2O. The bicyclooctane moiety comprises fused cyclopentane and cyclohexenone rings which are almost coplanar. An intermolecular O—H...O hydrogen bond links the 4′‐OH and 5′‐OCH3 groups along the c axis. 相似文献
35.
The methanolysis of the Cu(II) complex of N-acetyl-N,N-bis(2-picolyl)amine (2) was investigated by a kinetic study as a function of pH in methanol at 25 °C and computationally by DFT calculations. The active species is the basic form of the complex (3(-)), or (1:Cu(II))((-)OCH(3))(HOCH(3))), and the rate constant for its solvolysis is k(max) = 1.5 × 10(-4) s(-1). The mechanism involves Cu(II) binding to the amide N lone pair, decoupling it from >N-C═O resonance, concomitant with Cu(II):((-)OCH(3)) delivery to the adjacent >N-C═O unit, followed by Cu(II)-assisted departure of the N,N-bis(2-picolyl)amide from a tetrahedral intermediate. 相似文献
36.
37.
Griselda Barrera Galland Luciana P. Da Silva Marcos L. Dias Geraldo L. Crossetti Cludio M. Ziglio Carlos A. L. Filgueiras 《Journal of polymer science. Part A, Polymer chemistry》2004,42(9):2171-2178
A complete 13C NMR characterization of a polymer synthesized with a new Ni‐diimine complex [DADNi(NCS)2, where DAD = 2,6‐iPr? C6H3? N?C(Me)? C(Me)? N? 2,6‐iPr? C6H3] activated by methylaluminoxane by homopolymerization of propylene is presented. The amorphous material was made up mainly of blocks of syndiotactic polypropylene and ethylene–propylene copolymer. Some degree of propylene inversion (<1.2 mol %) and of long isobutyl and 2‐methyl hexyl branching (<1 mol %) were assigned and quantified. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2171–2178, 2004 相似文献
38.
Erin Hart Alex Klein Maribel Barrera Megan Jodray Karen Rodriguez 《Physics and Chemistry of Liquids》2018,56(6):821-833
Experimental solubilities were measured for 20 crystalline organic solutes dissolved in propanenitrile and for 13 crystalline organic solutes dissolved in butanenitrile at 298.15 K. Infinite dilution activity coefficient data for solutes dissolved in propanenitrile and butanenitrile have been compiled from the published chemical and engineering literature and converted into gas-to-liquid partition coefficients and water-to-organic solvent partition coefficients through standard thermodynamic relationships. Abraham model correlations were developed for describing solute transfer into both propanenitrile and butanenitrile by combining our measured solubility data with the partition coefficients that we calculated from the published activity coefficient data. The derived Abraham model correlations were found to back-calculate the observed partition coefficients and molar solubility data to within 0.14 log units. 相似文献
39.
The reaction of 2-(1-methyl-2-piperidinyl)ethanethiol with sodium tetrachloro-palladate(II) at pH = 8 yields a yellow precipitate of formula [Pd2(C8H16NS)2Cl2] which crystallized in the orthorhombic space group Pcab with a = 22.050(4) Å, b = 14.644(3) Å, c = 13.834(3) Å, V = 4467(3) Å3, and Z = 8. The organic ligands chelate to one Pd atom through the S and N atoms and bridges to another Pd atom through the S atom to form a dimer in which each molecule of the organic ligand has the same chirality. IR, UV—Vis and 1H NMR spectra are presented for this compound. 相似文献
40.
Summary This article describes some complexes of cobalt(III) with -mercaptopropylamine,N, N-dimethyl--mercaptopropylamme andN,N-dimethyl--mercaptoethylamine. The compounds are of stoichiometry [Co(ligand)3], [Co3(ligand)6]X (X=Cl or Br) and [Co(ligand)3]X3 (X=Cl or ClO4).
-Mercaptopropylamine yields both chelated and non-chelated compounds while theN,N-dimethyl derivatives yield only non-chelated complexes. This behaviour contrasts with the results obtained with nickel(II). 相似文献