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S. A. Kusmanov I. G. Dyakov Yu. V. Kusmanova P. N. Belkin 《Plasma Chemistry and Plasma Processing》2016,36(5):1271-1286
This study investigates the effect of the plasma electrolytic nitrocarburising conditions and electrolyte composition (NH4Cl, NH4NO3 and glycerol) on steel structure and properties. The cross-sectional microstructure, composition and phase constituents of a modified layer are characterized. The thickness of each layer is determined by carbon and nitrogen diffusion, anode dissolution, and oxidation that occur simultaneously. These processes are affected by the concentration of electrolyte components. The aqueous solution containing NH4NO3, NH4Cl and glycerol enables to obtain the modified layer with the thickness of 0.20 mm and hardness of 930 HV, the decrease in the surface roughness from 1.01 to 0.15 µm, the corrosion rate by a factor of 4.4 and the weight loss after lubricate wear testing by a factor of 14. 相似文献
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A whole-cell bacterial sensor system for short-chain halo-organic acids was constructed, using 2-chloropropionic acid (2-CPA) as a model pollutant. An Escherichia coli host was transformed with a moderate-copy plasmid containing a fusion of two foreign genetic elements: (a) a promoter-containing segment of the Pseudomonas DL-DEX (DL-2-haloacid dehalogenase) encoding gene and (b) bioluminescence (luxCDABE) genes of Photorhabdus luminescens. The resulting construct, named MT1, responded to the presence of 2-CPA by dose-dependent light emission, in a highly specific albeit a very insensitive manner. Thus, while the desired concept was successfully demonstrated, further genetic work is needed in order to make such a construct practical for environmental monitoring purposes. 相似文献
5.
We report a new kind of broadly tunable optical bandpass filters based on unusual properties of long-range surface plasmon polaritons. A 0.004 variation in the refractive index of the dielectric medium translates into 210 nm of bandpass tuning at telecom wavelengths. The tuning mechanism reported here may be used to create compact and widely tunable optical systems and other plasmonic components with broadly tunable optical response. 相似文献
6.
Translated from Matematicheskie Modeli i Vychislitel'nye Metody, pp. 174–184, 1987. 相似文献
7.
The kinetics of the autocatalytic reactions of formaldehyde with copper(II) and copper(I) oxides and with the Cu2+ ion of the copper EDTA complex, as well as formaldehyde disproportionation in the presence of copper metal, have been investigated
in aqueous solutions of sodium hydroxide. Two likely reaction mechanisms are presented. The difference between these mechanisms
does not alter the observed kinetics of the processes, whose rate is determined by their first, slow step, namely, the oxidation
of the methylene glycol anion adsorbed on the copper surface into formic acid. In the slow step of the first mechanism, a
hydride ion is abstracted from the methylene glycol anion and is transferred to copper. In the slow step of the second mechanism,
the methylene glycol anion undergoes anodic oxidation, releasing a hydrogen atom and an electron. In the rapid steps of the
first mechanism, the hydride ion undergoes anodic oxidation to hydrogen, the copper compound undergoes cathodic reduction
to copper metal, and, simultaneously, the electron and hydrogen are transferred to a nonionized formaldehyde molecule to yield
methanol. Mathematical models are suggested for the reactions. The effective rate constants and activation energies of the
slow steps of the reactions have been determined. The effective rate constants of the noncatalytic reduction reactions of
the copper compounds and the ratios of the rates of the rapid hydrogen and methanol formation reactions have been estimated. 相似文献
8.
Biran A Ben Yoav H Yagur-Kroll S Pedahzur R Buchinger S Shacham-Diamand Y Reifferscheid G Belkin S 《Analytical and bioanalytical chemistry》2011,400(9):3013-3024
A bacterial genotoxicity reporter strain was constructed in which the tightly controlled strong promoter of the Escherichia coli SOS response gene sulA was fused to the alkaline phosphatase-coding phoA reporter gene. The bioreporter responded in a dose-dependent manner to three model DNA-damaging agents—hydrogen peroxide,
nalidixic acid (NA), and mitomycin C (MMC)—detected 30–60 min after exposure. Detection thresholds were 0.15 μM for MMC, 7.5 μM
for nalidixic acid, and approximately 50 μM for hydrogen peroxide. A similar response to NA was observed when the bioreporter
was integrated into a specially designed, portable electrochemical detection platform. Reporter sensitivity was further enhanced
by single and double knockout mutations that enhanced cell membrane permeability (rfaE) and inhibited DNA damage repair mechanisms (umuD, uvrA). The rfaE mutants displayed a five- and tenfold increase in sensitivity to MMC and NA, respectively, while the uvrA mutation was advantageous in the detection of hydrogen peroxide. A similar sensitivity was displayed by the double rfaE/uvrA mutant when challenged with the pre-genotoxic agents 2-amino-3-methylimidazo[4,5-f]quinoline and 2-aminoanthracene following
metabolic activation with an S9 mammalian liver fraction. 相似文献
9.
The last decade has witnessed a significant increase in interest in whole-cell biosensors for diverse applications, as well as a rapid and continuous expansion of array technologies. The combination of these two disciplines has yielded the notion of whole-cell array biosensors. We present a potential manifestation of this idea by describing the printing of a whole-cell bacterial bioreporters array. Exploiting natural bacterial tendency to adhere to positively charged abiotic surfaces, we describe immobilization and patterning of bacterial "spots" in the nanolitre volume range by a non-contact robotic printer. We show that the printed Escherichia coli-based sensor bacteria are immobilized on the surface, and retain their viability and biosensing activity for at least 2 months when kept at 4 °C. Immobilization efficiency was improved by manipulating the bacterial genetics (overproducing curli protein), the growth and the printing media (osmotic stress and osmoprotectants) and by a chemical modification of the inanimate surface (self-assembled layers of 3-aminopropyl-triethoxysilane). We suggest that the methodology presented herein may be applicable to the manufacturing of whole-cell sensor arrays for diverse high throughput applications. 相似文献
10.
V. P. Belkin 《Mathematical Notes》1977,22(3):676-678
In this note an example of a finite lattice not having a finite basis of quasiidentities and an analogous example for algebras
of the type <1, 1> are indicated.
Translated from Matematicheskie Zametki, Vol. 22, No. 3, pp. 335–338, September, 1977. 相似文献