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211.
G. R. Kiani N. Arsalani M. G. Hosseini A. A. Entezami 《Journal of the Iranian Chemical Society》2008,5(4):559-565
In this study, the electropolymerization of 3-methylthiophene (3-MT) was preformed in the presence of a catalytic amount 1- (2-pyrrolyl)-2-(2-thienyl) ethylene (PTE) by cyclic voltammetry in acetonitrile as a solvent and lithium perchlorate as the electrolyte on a glassy carbon (GC) electrode. First, PTE was synthesized via the Wittig reaction. The addition of a catalytic amount of PTE during the electropolymerization of 3-MT changes the cyclic voltammograms such that the analysis of cyclic voltammograms of poly(3-MT) shows a considerable increase in the electroactivity and redoxability. Furthermore, the presence of PTE during the electropolymerization of 3-MT increases the polymerization rate. The CV measurement of the electron transfer ferro/ferricyanide redox system using different modified GC electrodes shows that the rate of charge transfer for poly(3-MT) in the presence of PTE is greater than that of poly(3-MT) alone. The conductivity of the obtained polymers was determined by electrochemical impedance spectroscopy (EIS) in 3.5% NaCl (w/v) solutions. With the application of Zview(II) software to the EIS, we estimate the parameters of the proposed equivalent circuit, based on a physical model for the electrochemical behavior of coatings on the GC electrode, to be 15739 ohm cm2 for the charge transfer resistance (Rct) for poly(3-MT) alone and 9700 ohm cm2 for poly(3-MT) in the presence of PTE. Thus, the film of poly(3-MT) formed in the presence of PTE is more conductive. 相似文献
212.
213.
The variational integrators presented in [5] are applied to systems with holonomic constraints, yielding constrained higher order variational integrators that are an extension of the constrained Galerkin methods in [4]. The construction of the integrators bases on a discrete version of Hamilton's principle. The inheritance of qualitative properties associated to the solution of the dynamical system to the discrete solution is analysed. Furthermore, the convergence order of the integrators and the computational efficiency is investigated numerically. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
214.
Kinetic,Equilibrium and Isotherm Studies of Cadmium Removal from Aqueous Solutions by Oxidized Multi‐Walled Carbon Nanotubes and the Functionalized Ones with Thiosemicarbazide and Their Toxicity Investigations: A Comparison 下载免费PDF全文
The multi‐walled carbon nanotubes (MWCNTs) were first oxidized by nitric acid to form a MWCNT‐COOH. Then, it was modified with thiosemicarbazide to produce MWCNT‐semi. Thus, these carbon materials, MWCNTs, MWCNT‐COOH and MWCNT‐semi, have been used as efficient adsorbents for the removal of cadmium from aqueous solutions. The influence of variables including pH, concentration of the cadmium, amount of adsorbents and contact time was investigated by the batch method. The kinetic studies carried out using different kinetic models such as pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion models. The sorption process with each adsorbent was well described by pseudo‐second‐order kinetics which it was agreed well with the experimental data. The values of regression coefficient of various adsorption isotherms like Langmuir, Freundlich and Tempkin to obtain the characteristic parameters of each model have been carried out. The results showed which the Langmuir isotherm for all adsorbents and Tempkin model for MWCNT‐COOH and MWCNT‐semi was found to best represent the measured sorption data. Toxicity of these samples was evaluated in human embryonic kidney HEK293 and human breast cancer SKBR3 cell lines after culturing cells for 24 h. Cellular investigations showed that the modified MWCNTs in particular MWCNT‐semi have considerably significant toxic impact on SKBR3 as compared to HEK293 at concentration 3 µg/mL. 相似文献
215.
Mohammad Hossein Habibi Nassibeh Kiani 《Journal of Thermal Analysis and Calorimetry》2013,112(2):573-577
In this research, we present an experimental procedure to prepare single-phase α-Fe(III) oxide nanoparticles by thermal decomposition of five different precursors including: iron(III) citrate; Fe(C6H5O7), iron(III) acetylacetonate; Fe(C5H7O2)3, and iron(III) oxalate; Fe(C2O4)3, iron(III) acetate; Fe(C2H3O2)3, and the thermal curves obtained were analyzed. The influence of the thermal decomposition of precursors on the formation α-Fe2O3 was studied by differential thermal gravimetry and thermogravimetry. The synthesized powders were characterized by using X-ray diffraction and scanning electron microscopy. High quality iron oxide nanoparticles with narrow size distribution and average particle size between ca. 2 and 30 nm have been obtained. It was found that the iron precursors affect the temperatures of the pure α-Fe2O3 nanoparticle formation with different diameters; iron(III) citrate (29 nm), iron(III) acetylacetonate (37 nm), and iron(III) oxalate (24 nm). 相似文献
216.
Tapas Adak Marvin Hoffmann Sina Witzel Dr. Matthias Rudolph Prof. Dr. Andreas Dreuw Prof. Dr. A. Stephen K. Hashmi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15573-15580
An unprecedented direct atom-economic chemo- and regioselective hydroalkylation of chloroalkynes and an sp3-C−H alkynylation of bromoalkynes was achieved. The reaction partners are unfunctionalized ethers, alcohols, amides, and even non-activated hydrocarbons. We found that a household fluorescent bulb was able to excite a diaryl ketone, which then selectively abstracts a H-atom from an sp3-C−H bond. The product of a formal alkyne insertion into the sp3-C−H bond was obtained with chloroalkynes, providing valuable vinyl chlorides. The photo-organocatalytic hydrogen atom transfer strategy gives rise to a broad range of diversely functionalized olefins. When bromoalkynes are applied in the presence of a base, a chemoselectivity switch to an alkynylation is observed. This reaction can even be performed for the alkynylation of unactivated sp3-C−H bonds, in this case with a preference of the more substituted carbon. Accompanying quantum chemical calculations indicate a vinyl radical intermediate with pronounced linear coordination of the carbon radical center, thus enabling the formation of both diastereoisomers after H-atom abstraction, suggesting that the (Z)-diastereoisomer is preferred, which supports the experimentally observed (E/Z)-distribution. 相似文献
217.
Flow simulations (investigation of velocity and microrotation fields) were carried out by solving the mass, linear momentum, and angular momentum equations in Cosserat continuum mechanics with a semi-analytical semi-experimental method; for unsteady, pulsatile, laminar, and locally fully developed blood flow and validation, using experimental pressure distribution in a mildly tapered femoral artery of a living dog. Finally, we present a time-dependent profile and an approximated Gaussian equation for k v (a material quantity that shows influence of microrotation field on the stress tensor) in this article. 相似文献
218.
S. M. Mousavi S. Kiani M. Razavi Farmad A. Hemati B. Abbasi 《Journal of Dispersion Science and Technology》2013,34(1):123-129
In this article, the extraction of arsenic(V) from water by means of emulsion liquid membrane is investigated. The influence of operating factors such as stirring speed, concentration of sulfuric acid in the external aqueous phase, concentration of sodium sulfate in internal stripping phase, and concentration of carrier in the membrane phase on the extraction efficiency are investigated and their optimum values, which provide the maximum recovery of arsenic, are determined. Taguchi experimental design is used in order to reduce the number of experiments. The optimum amounts for the extraction of arsenic from water, based on the results, are: stirring speed, 500 rpm; concentration of sulfuric acid in the feed, 1.5 g mol/lit; concentration of reagent in internal phase, 1.5 g mol/lit; and concentration of carrier in 3 ml kerosene which is added to the membrane phase, 0.1 g mol/lit. 相似文献
219.
220.
Fardad Koohyar Abbas Ali Rostami Mohammad Javad Chaichi Farhoush Kiani 《Journal of solution chemistry》2011,40(7):1361-1370
Viscosities, refractive indices, and densities for ternary systems of (L-cysteine hydrochloride monohydrate [LCHCMH] + D-sorbitol
+ water) and (glycerol + D-sorbitol + water) and binary systems of ([LCHCMH] + water) and (D-sorbitol + water) have been measured
at several temperatures (between T=303.15 K and T=323.15 K) and mass fractions (0.1 to 0.8) at atmospheric pressure. For these mixtures, the experimental values of density
were correlated with an experimental equation and the experimental values of viscosity were correlated with the Jones-Dole
equation. 相似文献