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排序方式: 共有146条查询结果,搜索用时 15 毫秒
61.
Fei Li Bin Su Fernando Cortes Salazar Raheleh Partovi Nia Hubert H. Girault 《Electrochemistry communications》2009,11(2):473-476
Scanning electrochemical microscopy (SECM) was used to monitor in situ hydrogen peroxide (H2O2) produced at a polarized water/1,2-dichloroethane (DCE) interface. The water/DCE interface was formed between a DCE droplet containing decamethylferrocene (DMFc) supported on a solid electrode and an acidic aqueous solution. H2O2 was generated by reducing oxygen with DMFc at the water/DCE interface, and was detected with a SECM tip positioned in the vicinity of the interface using a substrate generation/tip collection mode. This work shows unambiguously how the H2O2 generation depends on the polarization of the liquid/liquid interface, and how proton-coupled electron transfer reactions can be controlled at liquid/liquid interfaces. 相似文献
62.
Daniel H. Cortes 《Journal of sound and vibration》2011,330(23):5558-5568
The design of ultrasound transducers, resonators and other piezoelectric devices usually requires the calculation of the resonance frequencies of piezoelectric plates. Recent studies have shown that the resonance frequencies for plates in vacuum correspond to frequencies where the waveguide group velocity vanishes (zero-group-velocity points). However, those studies are limited to vacuum boundary conditions. The objective of the present study is to analyze the resonance frequencies of layered piezoelectric plates in contact with solid and fluid half-spaces and their relation to the dispersion behavior of the elastic guided wave propagation. Theoretical analysis using partial-wave approach of leaky Lamb waves is performed to study wave propagation in, and resonance behavior of, multilayered plates in contact with solid and fluid half-spaces. A novel observation resulted from this analysis is that, for plates in contact with solid and fluid half-spaces, the resonance frequencies occur at points where the magnitude of the wavenumber reaches a minimum. This frequency is named as a ‘transition frequency’. Such observations are important because they allow an easy identification of resonance frequencies with high amplitude response directly from the dispersion curves. This study will be helpful for the design of piezoelectric components used for resonators and sensors. 相似文献
63.
Garcia Idoia Cortes Kulchytska-Ruchka Iryna Schöps Sebastian 《Numerical Algorithms》2022,91(1):389-412
Numerical Algorithms - This article proposes modifications of the Parareal algorithm for its application to higher index differential algebraic equations (DAEs). It is based on the idea of applying... 相似文献
64.
Dr. Jean‐François Margathe Dr. Xavier Iturrioz Pierre Regenass Iuliia A. Karpenko Dr. Nicolas Humbert Dr. Hugues de Rocquigny Prof. Marcel Hibert Dr. Catherine Llorens‐Cortes Dr. Dominique Bonnet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(4):1399-1405
Herein, we develop a convenient method to facilitate the solution‐phase fluorescent labelling of peptides based on the chemoselective acylation of α‐hydrazinopeptides. This approach combines the advantages of using commercially available amine‐reactive dyes and very mild conditions, which are fully compatible with the chemical sensitivity of the dyes. The usefulness of this approach was demonstrated by the labelling of apelin‐13 peptide. Various fluorescent probes were readily synthesized, enabling the rapid optimization of their affinities for the apelin receptor. Thus, the first far‐red fluorescent ligand with sub‐nanomolar affinity for the apelin receptor was characterized and shown to track the receptor efficiently in living cells by fluorescence confocal microscopy. 相似文献
65.
66.
R. X. Valenzuela E. A. Mamedov V. Cortes Corberan 《Reaction Kinetics and Catalysis Letters》1995,55(1):213-220
The addition of K2O, Cr2O3, Sm2O3 or Nb2O5 to V–Mg–O catalyst decreased both activity and selectivity in propane oxydehydrogenation. By comparing these results with the characterization data, a relationship between propylene selectivity and catalyst reducibility was revealed. The most easily reduced catalyst was the most selective. 相似文献
67.
J. L. Iborra E. Cortes A. Manjon J. Ferragut F. Llorca 《Applied biochemistry and biotechnology》1976,1(1):91-100
Benzoic acid is a competitive inhibitor of the enzyme dopa-oxidase. p-Aminobenzoic acid was coupled by a single-step reaction of the amino group to: (1) CNBr-activated Sepharose 4B: (2) Enzacryl AA, by reaction with thiophosgene (pH 10.0); and (3) CM-Sephadex G-50, modified to azide by the Curtis procedure. These three solid supports were used as affinity adsorbents in the dopa-oxidase purification. The enzyme was obtained from frog epidermis, and was retained at pH 4.7 with 0.1 M acetate buffer. The enzyme elution was carried out using a linear pH gradient with 0.1 M phosphate buffer pH 8.0. We have examined the interaction of the enzyme with the immobilized PABA in relation to the nature of the support, the lengthening of the “arm” of the ligand, bathwise adsorption, and the enzyme activation by immobilized trypsin. 相似文献
68.
Yves Charreire Robert Cortes E. Nyk?nen L. Niinist? P. Soininen Markku Leskel? 《Fresenius' Journal of Analytical Chemistry》1998,362(1):41-50
Extended X-ray absorption fine structure (EXAFS) was used to determine the local structure of the luminescent centers in
Tb3+ and Ce3+ -doped strontium sulfide thin films deposited by Atomic Layer Epitaxy (ALE). The rare earths were observed to enter mainly
the substitutional sites but at the same time a part of the atoms form RES clusters (RE = rare earth). The presence of both
substitutional sites and RES clusters has been observed for the first time in this study for rare earths in II–VI compounds.
Received: 9 February 1998 / Revised: 22 May 1998 / Accepted: 29 May 1998 相似文献
69.
A novel system for sample introduction into a Gas Chromatograph (GC) using an automated in-column pyrolysis device has been
developed. The in-column pyrolysis device is suitable for use with any GC or GC-MS system. Solid samples are dissolved or
emulsions can be diluted and injected into the system. Because the system is designed for introducing liquid samples, a better
control of the injected sample amounts is achieved. This leads to high reproducibility of the peak areas, offering new opportunities
for quantitation of polymers or other high molecular weight materials. In addition, a better statistical representation of
the material to be analyzed is given if the samples are dissolved in a solvent. The system can be operated both in a normal
GC injection mode, and in the pyrolysis mode. As a conventional GC injector working in on-column or Programmed Temperature
Vaporization (PTV) injection mode, (without the pyrolysis function), information on the volatile fraction of a sample can
be obtained. Once the volatile materials in the sample have been separated, a second analysis on the non-volatile matrix can
be performed by initiating the pyrolysis sequence, yielding information on the non-volatile fraction of the sample. Both features,
on column or PTV injection mode and in-column pyrolysis can be used separately or in combination. This new technology is expected
to be useful for the determination of additives, monomers, solvents and other volatile components in a non volatile matrix,
such as polymers, as well as in the characterization of the non-volatile matrix itself, in a single run.
Revised: 20 June and 21 July 2005 相似文献
70.
Maurizio Vannoni Idoia Freijo Martín Harald Sinn 《Journal of synchrotron radiation》2016,23(4):855-860
One of the classical devices used to tune a mirror on an X‐ray optical setup is a mechanical bender. This is often designed in such a way that the mirror is held with clamps on both ends; a motor is then used to put a torque on the clamps, inducing a cylindrical shape of the mirror surface. A mechanical bender with this design was recently characterized, to bend a 950 mm‐long mirror up to a radius of curvature of 10 km. The characterization was performed using a large‐aperture Fizeau interferometer with an angled incidence setup. Some particular and critical effects were investigated, such as calibration, hysteresis, twisting and long‐term stability. 相似文献