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41.
In a recent paper in this journal [Q. Guo, L. Gao, Distribution of individual incomes in China between 1992 and 2009, Physica A 391 (2012) 5139–5145], a new family of distributions for modeling individual incomes in China was proposed. This family is the so-called Modified Gaussian (MG) distribution, which depends on two parameters. The MG distribution shows a satisfactory fit for the individual income data between 1992 and 2009. However, for the practical use of this model with individual incomes, it is necessary to know its probabilistic and statistical properties, especially the corresponding inequality measures. In this paper, probabilistic functions and inequality measures of the MG distribution are obtained in closed form, including the normalizing constant, probability functions, moments, first-degree stochastic dominance conditions, relationships with other families of distributions and standard tools for inequality measurement (Lorenz and generalized Lorenz curves and Gini, Donaldson–Weymark–Kakwani and Pietra indices). Several methods for parameter estimation are also discussed. In order to illustrate all the previous formulations, we have fitted individual incomes of Spain for three years using the European community household panel survey, concluding a static pattern of inequality, since the Gini index and other inequality measures remain constant over the study period. 相似文献
42.
Ignasi Burgués‐Ceballos Mariano Campoy‐Quiles Laia Francesch Paul D. Lacharmoise 《Journal of Polymer Science.Polymer Physics》2012,50(17):1245-1252
The viability of vapor printing as a fast annealing treatment for the processing of polymer solar cells is demonstrated. In this method, a carrier gas transporting vapor solvent is delivered through a nozzle promoting self‐assembly of polymer chains. Devices based on poly(3‐hexylthiophene) blended with soluble fullerene are locally exposed during different annealing times to chlorobenzene vapor in a nitrogen flow. This enables finding an optimal nanostructure in promisingly short time‐scales (<5 s of exposure to vapor solvent), which yields a twofold increase in efficiency with respect to as‐cast samples. Moreover, a combined Raman, photometric, and ellipsometric characterization allows to understand why overexposure to vapor solvent reduces the performance. Finally, toluene and 1,2,3,4‐tetrahydronaphthalene are also tested using this method, showing different printing efficiencies corresponding to their specific vapor pressures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
43.
Carmen Rodríguez Robelo Vanesa Zazueta Novoa Roberto Zazueta-Sandoval 《Applied biochemistry and biotechnology》2004,113(1-3):161-171
Soluble alcohol oxidase (AO) activity was detected in the supernatant fraction of a high-speed centrifugation procedure after
ballistic cellular homogenization to break the mycelium from a filamentous fungus strain named YR-1, isolated from petroleum-contaminated
soils. AO activity from aerobically grown mycelium was detected in growth media containing different carbon sources, including
alcohols and hydrocarbons but not in glucose. In previous work, zymogram analysis conducted with crude extracts from aerobic
mycelium of YR-1 strain indicated the existence of two AO enzymes originally named AO-1 and AO-2. In the present study, we
were able to separate the AO-1 band into two bands depending on culture conditions, carbon source, and polyacrylamide gel
electrophoresis (PAGE) separation conditions; the enzyme activity pattern in zymograms from cell-free extracts exhibited three
different bands after native PAGE. New nomenclature was used for upper bands AO-1 and AO-2 and lower band AO-3, respectively.
The expression of AO activity was studied in the absence of glucose in the culture media and in the presence of hydrocarbons
or petroleum as sole carbon source, suggesting that AO expression could be subjected to two regulatory possibilities: carbon
catabolite regulation by glucose and induction by hydrocarbons. The possibility of catabolic inhibition of AO by glucose in
the active enzyme was also tested, and the results confirm that this kind of regulatory mechanism is not present in AO activity. 相似文献
44.
Alvarado-Caudillo Yolanda Torres José Carlos Bravo Novoa Vanesa Zazueta Jiménez Hortencia Silva Torres-Guzmán J. Carlos Gutiérrez-Corona J. Félix Zazueta-Sandoval Roberto 《Applied biochemistry and biotechnology》2002,98(1-9):243-255
A soluble alcohol oxidase (AO) activity was detected in the mycelium of a filamentous fungus strain named YR-1, isolated from
petroleum-contaminated soils. AO activity from aerobically grown mycelium was detected in growth media containing the hydrocarbons
decane or hexadecane; the enzyme activity exhibited optimum pH for the oxidation of different alcohols (methanol, ethanol,
and hexadecanol) similar to that of the corresponding aldehyde. Zymogram analysis conducted with purified fractions from aerobic
mycelium of YR-1 strain extracts indicated the existence of two AO enzymes (AO-1 and AO-2). Purified samples of both enzymes
analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis indicated the presence of three protein bands with molecular
sizes 20, 38, and 46 kDa that could be part of the native enzyme. In samples of both enzymes, the 46-kDa protein gave a positive
reaction in immunodetection experiments with antibodies directed against AO from Hansenula polymorpha. The purified AO-2 enzyme oxidized different alcohols, although higher activity was displayed with hexadecanol. K
m
values obtained for methanol and hexa-decanol indicated a higher affinity for the latter. Analysis of the aminoter-minal
sequence of the 46-kDa protein of AO-2 enzyme indicated significant similarity to enzymes involved in the metabolism of biphenyl
polychloride compounds. 相似文献
45.
A novel approach for CE data analysis based on pattern recognition techniques in the wavelet domain is presented. Low-resolution, denoised electropherograms are obtained by applying several preprocessing algorithms including denoising, baseline correction, and detection of the region of interest in the wavelet domain. The resultant signals are mapped into character sequences using first derivative information and multilevel peak height quantization. Next, a local alignment algorithm is applied on the coded sequences for peak pattern recognition. We also propose 2-D and 3-D representations of the found patterns for fast visual evaluation of the variability of chemical substances concentration in the analyzed samples. The proposed approach is tested on the analysis of intracerebral microdialysate data obtained by CE and LIF detection, achieving a correct detection rate of about 85% with a processing time of less than 0.3 s per 25,000-point electropherogram. Using a local alignment algorithm on low-resolution denoised electropherograms might have a great impact on high-throughput CE since the proposed methodology will substitute automatic fast pattern recognition analysis for slow, human based time-consuming visual pattern recognition methods. 相似文献
46.
Penno D Lillo V Koshevoy IO Sanaú M Ubeda MA Lahuerta P Fernández E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(34):10648-10655
Novel Pd(2) (6+) compounds have been synthesized in high yield. These compounds and their Pd(2) (4+) counterparts as synthetic precursors mediate the diboration of vinylarenes and aliphatic 1-alkenes, and under mild and basic reaction conditions they produce a variety of 1,2-diboronate esters with excellent conversions and chemoselectivities. The presence of bis(catecholato)diboron (B(2)cat(2)) favours the reduction of Pd(III) to Pd(II), while the catalytic precursor of Pd(II) is transformed into Pd(0)-nanoparticles. An "in situ" catalytic tandem reaction has been designed to transform the diboronate intermediates into the monoarylated product, which after oxidative workup, provides the carbohydroxylated adduct. Eventually, the same catalyst performs both sequences with total conversion from the alkene. 相似文献
47.
Uric acid (UA) is determined using the UV-vis molecular absorption properties of peroxidase (HRP). The method as a whole involves UA oxidation in the presence of uricase (UOx), giving H2O2. The H2O2 then reacts with HRP forming the compound I species which returns to its initial form by reaction with UA and intramolecular reduction. The molecular absorption changes of HRP at 420 nm during the reaction enable the UA to be determined. A mathematical model relating the analytical signal to UA, UOx and HRP has been developed and experimentally validated. The possibility of carrying out both enzymatic reactions sequentially or simultaneously is discussed, the latter option producing better analytical performances. The method permits UA determination in the range 1.5 × 10−6-4.0 × 10−5 M, with an R.S.D. of about 3% (n = 5, 1.5 × 10−6 M UA). It has been applied to analyte determination in synthetic serum samples. 相似文献
48.
Roads less traveled: Nitrogen reduction reaction catalyst design strategies for improved selectivity
Bianca M. Ceballos Ghanshyam Pilania Kannan P. Ramaiyan Amitava Banerjee Cortney Kreller Rangachary Mukundan 《Current Opinion in Electrochemistry》2021
Direct electrochemical nitrogen reduction for ammonia production is necessary to reduce the use of fossil fuels from conventional Haber–Bosch methods. Applications of nitrogen reduction electrocatalysts remain inhibited by slow reaction kinetics and low faradaic efficiencies because of competitive H2 production pathways. Current strategies to address this challenge in selectivity have focused on catalyst design, reactor configuration, and electrolyte conditions. This brief review discusses the thermodynamic and kinetic challenges in the field as well as current underused approaches for selective catalyst development including bimetallic catalysts, transition metal nitrides, and carbon supports. 相似文献
49.
Nieves Baenas Celia Iniesta Rocío Gonzlez-Barrio Vanesa Nuez-Gmez María Jesús Periago Francisco Javier García-Alonso 《Molecules (Basel, Switzerland)》2021,26(7)
Different strategies have been developed to increase the concentration of bioactive compounds in tomatoes during post-harvest, with ultraviolet light (UV) and light emitting diodes (LEDs) being interesting tools. The aim of this study was to evaluate the effect of ultraviolet (UVA at 366 nm and UVC at 254 nm) pre-treatment (1 kJ/m2) and red–blue LED light (25.4 µmol/m2/s) on the concentration of carotenoids, (poly)phenols and hydrophilic/lipophilic antioxidant capacity during 7 days of refrigeration storage of green tomatoes (Solanum lycopersicum L.) cultivar “Raf”. In addition, special attention was paid to quality parameters (weight loss, colour, acidity, soluble solids and ripening index). Tomatoes exposed to LED light at 6 °C for 7 days increased up to three times the total carotenoids content (mainly β-carotene and E-lycopene) compared to tomatoes refrigerated in the dark, while UV treatments alone did not significantly affect the carotenoid content. Besides, exposure to LEDs increased the hydrophilic and lipophilic antioxidant capacity of tomatoes by 30%, without affecting phenolic contents. Thus, LED treatments alone during refrigerated storage fostered ripening and improved the nutritional value of tomatoes, without compromising quality parameters. Further studies must be carried out to evaluate the impact on sensory attributes and consumer acceptance. 相似文献
50.
Asymmetric synthesis of α-alkyl α-selenocarbonyl compounds catalyzed by bifunctional organocatalysts
A new organocatalytic approach for the synthesis of a variety of α-alkyl, α-phenylselenyl ketones as well as their corresponding esters and amides, by the addition of α-selenocarbonyl derivatives to nitroalkenes catalyzed by thiourea or squaramide cinchona catalysts, is presented. This catalytic system allows the preparation in high yields of enantiomerically enriched selenocarbonyl derivatives bearing two chiral centers with excellent ee's and dr's by using catalytic loadings of 3 mol%. 相似文献