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21.
Mohammad Navid Soltani Rad Somayeh Behrouz Abdollah Movahedian Mohammad Mahdi Doroodmand Younes Ghasemi Sara Rasoul‐Amini Abdol‐Rasoul Ahmadi Gandomani Ramin Rezaie 《Helvetica chimica acta》2013,96(4):688-701
A facile and simple protocol for the 1,3‐dipolar cycloaddition of organic azides with terminal alkynes catalyzed by doped nano‐sized Cu2O on melamine? formaldehyde resin (nano‐Cu2O? MFR) as a new and convenient heterogeneous catalyst is described. In this method, ‘click’ cycloaddition of various structurally diverse β‐azido alcohols and alkynes in the presence of nano‐Cu2O? MFR in H2O/THF 1 : 2 furnished the corresponding 1,4‐disubstituted 1H‐1,2,3‐triazole adducts 1a – 1o in good to excellent yields at room temperature (Scheme and Table 3). The nano‐Cu2O? MFR was characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), inductively coupled plasma (ICP) analysis, and FT‐IR. The nano‐Cu2O? MFR could be easily recovered and recycled from the reaction mixture and reused for many consecutive trials without significant decrease in activity (Table 4). The in vitro antibacterial activities of all synthesized compounds were tested on several Gram‐positive and/or Gram‐negative bacteria (Table 5). The results demonstrate the promising antibacterial activity for some of the synthesized compounds. 相似文献
22.
Ali Sarafraz-Yazdi Farideh Mofazzeli Zarrin Es'haghi 《International journal of environmental analytical chemistry》2013,93(14-15):1108-1118
A new sample preparation method named directly suspended droplet liquid-liquid-liquid phase microextraction was used in this research for determination of three chlorophenols in environmental water samples. The analytes (2-chlorophenol, 3-chlorophenol and 4-chlorophenol) were extracted from 4.5?mL acidic donor phase, (pH 2, P1) into an organic phase, 350?µL?of benzene/1-octanol (90?:?10 v/v, P2) and then were back-extracted into a 7?µL droplet of an basic (pH 13) aqueous solution (acceptor phase, P3). In this method, contrary to the ordinary single drop liquid-phase microextraction technique, an aqueous large droplet is freely suspended on the surface of the organic solvent, without using a microsyringe as supporting device. This aqueous microdroplet is delivered at the top-centre position of an immiscible organic solvent which is laid over the aqueous donor sample solution while the solution is being agitated. Then, the acceptor phase containing chlorophenols was withdrawn back into a HPLC microsyringe and neutralised by adding of 7?µL HCl 0.1?M. The total amount was eventually injected into the HPLC system with UV detection at 225?nm for further analysis. Parameters such as the organic solvent, phases volumes, extraction and back-extraction times, stirring rate and pH values were optimised. The calibration graphs are linear in the range of 10–2000?µg?L?1 with r?≥?0.9973. The enrichment factors were ranged from 115 to 170, and the limit of detection (LOD, n?=?7) varied from 5 to 10?µg?L?1. The relative standard deviations (RSDs, n?=?5) were found 6.8 to 7.4 at S/N?=?3. All experiments were carried out at room temperature, (22?±?0.5°C). 相似文献
23.
Titanium dioxide is a semiconductor with excellent photo catalytic properties and an important material with high regarded in nanotechnology. In this study, titanium dioxide nanoparticles was successfully synthesized via sol–gel method using tetra-n-butyl orthotitanate, hydrochloric acid and ammonia. Tetra-n-butyl orthotitanate was used as precursor. The ingredients were mixed at ambient temperature for 9 h on a magnetic stirring, sol was formed and converted to gel by adding ammonia. X-ray diffraction analysis clearly showed anatase and rutile phases so that, with increasing calcination temperature anatase converts to the rutile. Scanning electron microscopy was used for agglomerate observations. Energy-dispersive detector analysis was carried out and confirmed the formation of titanium dioxide. The influences of calcination temperature and pH value on particles size were studied. The results indicate that synthesis at room temperature reduced the particle size to 15 nm. 相似文献
24.
O. Ghasemi H. Ghanbariadivi V. Ghasemi 《Journal of Dispersion Science and Technology》2014,35(5):706-716
This article has been retracted. 相似文献
25.
Mohammadi Ziarani Ghodsi Khademi Mahdieh Mohajer Fatemeh Anafcheh Maryam Badiei Alireza Ghasemi Jahan B. 《Research on Chemical Intermediates》2022,48(5):2111-2133
Research on Chemical Intermediates - The synthesis of 4-Aryl-(3,5-dimethyl-1,4,7,8-tetrahydro-dipyrazolo[3,4b:4′,3′e]pyridine derivatives was accomplished using Fe3O4@SiO2@(BuSO3H)3... 相似文献
26.
Ghasemi Mahdi Niknejadi Mohammadreza Toghraie Davood 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2483-2495
Journal of Thermal Analysis and Calorimetry - The thermal behavior of CuO-water nanofluid is examined on an aluminum surface. The dimensions of simulation boxes are... 相似文献
27.
There is a high overvoltage in the oxidation of methanol in fuel cells,and so modified electrodes are used to decrease it.A modified electrode that used Ni(II) loaded analcime zeolite to catalyze the electrooxidation of methanol in alkaline solution was proposed.Analcime zeolite was synthesized by hydrothermal synthesis,and Ni(II) ions were incorporated into the analcime structure,which was then mixed with carbon paste to prepare modified electrode.The electrocatalytic oxidation of methanol on the surface of the modified electrode in alkaline solution was investigated by cyclic voltammetry and chronoamperometry.The effects of the scan rate of the potential,concentration of methanol,and amount of zeolite were investigated.The rate constant for the catalytic reaction of methanol was 6 × 103 cm3 mol-1 s-1 from measurements using chronoamperometry.The proposed electrode significantly improved the electron transfer rate and decreased the overpotential for methanol oxidation. 相似文献
28.
Research on Chemical Intermediates - An effective synthesis of anion-exchanged supported ionic liquid using magnetically separable nanoparticles and its catalytic effect on N-alkylation reactions... 相似文献
29.
The naturally occurring ant venom (13E,15E,18Z,20Z)-1-hydroxypentacosa-13,15,18,20-tetraen-11-yn-4-one 1-acetate was synthesized stereospecifically using a series of metal-mediated cross-coupling reactions. The use of the difunctional olefin template (E)-1-chloro-2-iodoethylene as the central, pseudosymmetrical building block facilitated a fully convergent and, thus, efficient strategy to prepare this polyunsaturated natural product. 相似文献
30.
Jahan B. Ghasemi Shabnam Hooshmand Saeed Rayati 《Journal of inclusion phenomena and macrocyclic chemistry》2013,76(1-2):47-54
A novel, fast and easy single sample measurement has been developed based upon temperature dependence of equilibrium constant in order to determine the enthalpy and entropy changes of a complexation reaction using spectrophotometric temperature titration. The method can be used in determination of the formation constant and thermodynamic parameters of the solutions that there are difficulties in their titration where volatile compounds are studying. Knowledge of component spectra is not required for the analysis. The formation constants of the interactions of ß-di and tri-brominated meso-tetraphenylporphyrins, and meso-tetrakis(4-methylphenyl) and (4-methoxyphenyl) porphyrins with Me2SnCl2 and Bu2SnCl2, have been determined in range of 0–25 °C utilizing van’t Hoff relation, mass balance and equilibrium constant equations by an iterative least squares method with ΔH 0 as adjustable parameter. The outputs of analysis are the equilibrium constants, ligand and adduct spectral profiles, their concentrations as a function of temperature, the adjusted values of the standard enthalpy ΔH 0, and entropy ΔS 0 changes. The order of formation constants of the resulting 1:1 complexes decreased with increasing number of bromide substituents and increased with adding methyl and methoxy groups, and vary as H2T(4-CH3O)PP > H2T(4-CH3)PP > H2TPP > H2TPPBr2 > H2TPPBr3 and Me2SnCl2 > Bu2SnCl2. 相似文献