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51.
Vinay S. Sharma 《Molecular Crystals and Liquid Crystals》2017,643(1):52-61
In order to investigate the influence of the central linking group and effect on flexibility on mesophase behavior of liquid crystal we have synthesized newly homologous series viz. 3-(4-Octyloxyphenyl)-1-(4′-n-alkoxy phenyl) prop-2-en-1-one (Series-l) consists of thirteen homologues (C1 to C8, C10, C12, C14, C16, C18). Textures of a nematic phases are threaded or Schlieren type. The textures of smectic and nematic phase are directly judged from the heating and cooling condition. Group efficiency order for mesophases is derived on the basis of thermal stabilities from the comparative study of thermometric data determined from structurally analogous series. A transition curve as depicted in a phase diagram behaves in normal manner. Structural and conformational characterization of these new compounds had achieved by 1H NMR, 13C NMR, IR, and elemental analysis. 相似文献
52.
Vinay Kumar A. K. Bedyal J. Sharma V. Kumar O. M. Ntwaeaborwa H. C. Swart 《Applied Physics A: Materials Science & Processing》2014,116(4):1785-1792
In the present work, red-emitting Ca2V2O7:xEu3+ (x = 0.5–6.0 mol%) nanophosphors, in the form of powders, were synthesized by the citrate-gel combustion method using metal nitrates as precursors and citric acid as fuel. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy, photoluminescence (PL) and cathodoluminescence (CL) spectroscopy were used to study the structure, morphology and spectral properties of the samples. The chemical compositions and electronic states of the powders were analyzed with X-ray photoelectron spectroscopy. The average crystallite sizes estimated using the XRD data were found to be in the range of 30–45 nm, and were cross verified by TEM. The lattice parameters determined by the POWD program were approximated as a = 7.242 Å, b = 6.674 Å, c = 6.932 Å and V = 291.24 Å3, respectively. Under UV (395 nm) (PL) and electron (CL) excitation, the nanophosphors show characteristic emission from the Eu3+ ion (5D0 → 7Fj, j = 1–5) with the main peaks at 612 and 616 nm. The maximum emission intensity was recorded from the sample with an Eu3+ concentration of 4 mol% and a critical energy distance of 19.084 Å between the donor and the acceptor. Above this concentration, there was a reduction in the intensity due to dipole–dipole induced concentration quenching effects. The potential applications of this phosphor as a high color-purity phosphor in light-emitting diodes are evaluated. 相似文献
53.
54.
RF sputtered p-type nickel oxide (NiO) thin film exhibiting tunable semiconductor character which in turns enhanced its functional properties. NiO thin film with high hole mobility is developed as a potential matrix for the realization of glucose biosensor. NiO thin film prepared under the optimized deposition conditions offer good electrical conductivity (1.5 × 10−3 Ω−1-cm−1) with high hole mobility (2.8 cm2 V−1 s−1). The bioelectrode (GOx/NiO/ITO/glass) exhibits a low value of Michaelis–Menten constant (Km = 1.05 mM), indicating high affinity of the immobilized GOx toward the analyte (glucose). Due to the high surface coverage (2.32 × 10−7 mol cm−2) of the immobilized enzyme on to the NiO matrix and its high electrocatalytic activity, the prepared biosensor exhibits a high sensitivity of 0.1 mA (mM−1-cm−2) and a good linearity from 25 to 300 mg dL−1 of glucose concentration with fast response time of 5 s. Various functional properties of the material (mobility, crystallinity and stress) are found to influence the charge communication feature of NiO thin film matrix to a great extent, resulting in enhanced sensing response characteristics. 相似文献
55.
M. S. Raghu K. Basavaiah P. J. Ramesh Sameer A. M. Abdulrahman K. B. Vinay 《Journal of Applied Spectroscopy》2012,79(1):131-138
A sensitive, precise, and cost-effective UV-spectrophotometric method is described for the determination of pheniramine maleate
(PAM) in bulk drug and tablets. The method is based on the measurement of absorbance of a PAM solution in 0.1 N HCl at 264 nm.
As per the International Conference on Harmonization (ICH) guidelines, the method was validated for linearity, accuracy, precision,
limits of detection (LOD) and quantification (LOQ), and robustness and ruggedness. A linear relationship between absorbance
and concentration of PAM in the range of 2–40 μg/ml with a correlation coefficient (r) of 0.9998 was obtained. The LOD and
LOQ values were found to be 0.18 and 0.39 μg/ml PAM, respectively. The precision of the method was satisfactory: the value
of relative standard deviation (RSD) did not exceed 3.47%. The proposed method was applied successfully to the determination
of PAM in tablets with good accuracy and precision. Percentages of the label claims ranged from 101.8 to 102.01% with the
standard deviation (SD) from 0.64 to 0.72%. The accuracy of the method was further ascertained by recovery studies via a standard
addition procedure. In addition, the forced degradation of PAM was conducted in accordance with the ICH guidelines. Acidic
and basic hydrolysis, thermal stress, peroxide, and photolytic degradation were used to assess the stability-indicating power
of the method. A substantial degradation was observed during oxidative and alkaline degradations. No degradation was observed
under other stress conditions. 相似文献
56.
P. J. Ramesh K. Basavaiah O. Zenita Devi N. Rajendraprasad K. B. Vinay 《Journal of Analytical Chemistry》2012,67(6):595-599
Two titrimetric methods which are simple, rapid, cost-effective and eco-riendly are described for the determination of ofloxacin (OFX) in bulk drug and in tablet formulations based on the oxidation of OFX by Ce(IV) sulphate. In direct titrimetry (method A), the acidified solution of OFX is titrated directly with Ce(IV) sulphate using ferroin as indicator, and indirect titrimetry (method B) involves the addition of known excess of Ce(IV) sulphate to an acidified solution of OFX followed by the determination of unreacted oxidant by back titration with ferrous ammonium sulphate (FAS) using the same ferroin indicator. In both the methods, the amount of Ce(IV) sulphate reacted corresponds to OFX concentration. Method A and method B permit the determination of OFX over the concentration range of 1.5?C15 mg in both the methods and the quantitation is based on a 1: 5 reaction stoichiometry (OFX: Ce (IV) sulphate). The methods were statistically evaluated by calculating percent relative error (% RE) for accuracy and percent relative standard deviation (% RSD) for precision, and were applied successfully to the determination of OFX in tablets with mean recoveries in the range of 96.50?C98.42%. No interference was observed from common additives found in pharmaceutical preparations. The accuracy and reliability of the methods were further ascertained by performing recovery tests s standard-addition technique. 相似文献
57.
Kalsang Tharpa Kanakapura Basavaiah Kanakapura Basavaiah Vinay 《Journal of Analytical Chemistry》2012,67(4):335-339
Based on the nitrogenous base or quaternary ammonium moiety in isoxsuprine hydrochloride (ISX), two highly accurate and selective titrimetric methods are proposed f or the determination of ISX in spiked human urine,
injection and tablets. Non-aqueous titration (Method A) involves removal of protonated amine using mercuric acetate for enhanced
basic nitrogen prior to titration with perchloric acid in an acetic acid medium using crystal violet as indicator. Two-phase
titration (Method B) is based on ion association complex formation between sodium lauryl sulphate (SLS) and protonated amine of ISX at pH 2.5 in aqueous phase, end point being detected by change in dimethyl yellow color in chloroform
layer. The methods are applicable over the concentration range 2.0–20.0 mg and 1.0–10.0 mg for method A and method B, respectively.
Calculations are based on 1: 1 molar ratio, i.e., JSX: HClO4 for method A and ISX: SLS for method B, owing to the presence of one nitrogen atom. Method A is applicable to the determination
of ISX in tablets whereas method B is applicable to spiked human urine, injection and tablets. The methods are validated statistically
by comparing the results with those of the reference method by applying the Student’s t-test and F-test. The accuracy was further ascertained by recovery studies via standard addition technique. 相似文献
58.
We show how to determine whether a given pattern p of length m occurs in a given text t of length n in
time (where
allows for logarithmic factors in m and n/m) with inverse polynomial failure probability. This algorithm combines quantum searching algorithms with a technique from parallel string matching, called Deterministic Sampling. 相似文献
59.
J. D. Pandey A. K. Shukla Vinay Sanguri Siddharth Pandey 《Journal of solution chemistry》1995,24(11):1191-1196
Viscosity of quaternary non-electrolyte solution carbon tetrachloride+ cyclohexane+benzene+toluene has been experimentally determined at 25°C. Experimental results of viscosity have been analyzed in the light of PFP theory and BAB method. A comparative study of the two approaches has been made. Excellent agreement between theoretical and experimental findings is achieved. 相似文献
60.
New mixed metal chalcogenate coordination polymers, MPb(SCN)2(SeCN)2 [M = CoII, NiII or HgII], Ag2-Pb(SCN)2(SeCN)2, and the complex heterobimetallic salts, [M(phen)3][Pb(SCN)2(SeCN)2][M = CoII or NiII; phen = 1,10-phenanthroline] that have been prepared and characterized by elemental analyses, i.r. and u.v.–vis. spectra, and by powder XRD patterns. Their solid state electrical conductivities have been investigated, show
rt in the 10–10–10–6 S cm–1 range, and semiconduct at 313–383 K with band gaps in the 0.28–0.91 eV range. [Co(phen)3][Pb(SCN)2(SeCN)2], exhibits a remarkable increase, i.e. 104 order of magnitude, in conductivity at higher temperature, which reflects a disordered metallic system where charge carriers have difficulty in crossing the non-conducting barrier at low temperature. 相似文献