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1.
The determination of doxazosin by high-performance liquid chromatography with fluorescence detection is described. Propanolol was used as the internal standard. Plasma samples were treated with methanol to precipitate the proteins. Doxazosin was isolated with C18 reversed-phase extraction columns. The determination limit is 1 ng/ml of plasma, while the extraction columns can be reused frequently. The method is applied to clinical trial samples. 相似文献
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A quality check for an automated system of analyzing large sets of neutron activated samples has been developed. Activated
samples are counted with an HPGe detector, in conjunction with an automated sample changer and spectral analysis tools, controlled
by the Canberra GENIE 2K and REXX software. After each sample is acquired and analyzed, a Microsoft Visual Basic program imports
the results into a template Microsoft Excel file where the final concentrations, uncertainties, and detection limits are determined.
Standard reference materials are included in each set of 40 samples as a standard quality assurance/quality control (QA/QC)
test. A select group of sample spectra are also visually reviewed to check the peak fitting routines. A reference spectrum
was generated in MCNP 4c2 using an F8, pulse-height, tally with a detector model of the actual detector used in counting.
The detector model matches the detector resolution, energy calibration, and counting geometry. The generated spectrum also
contained a radioisotope matrix that was similar to what was expected in the samples. This spectrum can then be put through
the automated system and analyzed along with the other samples. The automated results are then compared to expected results
for QA/QC assurance. 相似文献
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5.
S.G. Schulman K. Abate P.J. Kovi A.C. Capomacchia D. Jackman 《Analytica chimica acta》1973,65(1):59-67
The fluorescences of 6- and 7-aminoquinoline and 6-dimethylaminoquinaldine were studied in media of different acidities, polarities, hydrogen-bonding capabilities and temperatures. The excited state acidities and solvent dependences of the fluorescences of these compounds are typical of aminoquinolines substituted in the homocyclic ring. The acidities of the doubly protonated cations are so great in the lowest excited singlet state, however, that prototropic dissociation in the excited state occurs even in rigid media at 195°K. The lowest triplet state of the singly charged cation of 6-aminoquinoline is found to be nearly degenerate with the lowest excited singlet state of the same molecule. This is attributed to the great charge-transfer component of the S1←S0 transition which is not present in the T1←S0 transition, and the interaction of the S1 state with the polar solvent. 相似文献
6.
An experimental study of the thermal decomposition of a β‐hydroxy alkene, 3‐methyl‐3‐buten‐1‐ol, in m‐xylene solution, has been carried out at five different temperatures in the range of 513.15–563.15 K. The temperature dependence of the rate constants for the decomposition of this compound in the corresponding Arrhenius equation is given by ln k (s?1) = (25.65 ± 1.52) ? (17,944 ± 814) (kJ·mol?1)·T?1. A computational study has been carried out at the M05–2X/6–31+G(d,p) level of theory to calculate the rate constants and the activation parameters by the classical transition state theory. There is a good agreement between the experimental and calculated rate constants and activation Gibbs energies. The bonding characteristics of reactant, transition state, and products have been investigated by the natural bond orbital analysis, which provides the natural atomic charges and the Wiberg bond indices. Based on the results obtained, the mechanism proposed is a one‐step process proceeding through a six‐membered cyclic transition state, being a concerted and slightly asynchronous process. The results have been compared with those obtained previously by us (Struct Chem 2013, 24, 1811–1816) for the thermal decomposition of 3‐buten‐1‐ol, in m‐xylene solution. We can conclude that in the compound studied in this work, 3‐methyl‐3‐buten‐1‐ol, the effect of substitution at position 3 by a weakly activating CH3 group is the stabilization of the transition state formed in the reaction and therefore a small increase in the rate of thermal decomposition. 相似文献
7.
Abstract Due to the wide use of polymers in medicine, researchers are required to solve a very important problem–to understand the interaction between materials of nonphysiological origin and the surrounding biological liquids, and tissues, particularly blood. 相似文献
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Dennis Earl Jackman 《Journal of heterocyclic chemistry》1990,27(4):1053-1057
A blue pigment which sometimes accompanies the manufacture of the triazine herbicide metribuzin ( 5 ) was identified as the novel thiadiazole formazan 10 which arises from the reaction of two impurities 3 and 7 . The latter compound is a keto acid derivative of 2,4-dihydrazinothiadiazole which in turn is an impurity in carbonothioic dihydrazide. Compound 7 has the interesting property of undergoing a facile oxidative decarboxylation in the presence of alcohols to form hydrazonate esters and in the presence of aliphatic amines to form red amidrazone dyes 9 . The N-substituted dyes can be oxidized to ditriazolothiadiazoles 12 . 相似文献
10.
Olga Riba Robert J. Barnes Thomas B. Scott Murray N. Gardner Simon A. Jackman Ian P. Thompson 《Journal of nanoparticle research》2011,13(10):4591-4601
A reactivity study was undertaken to compare and assess the rate of dechlorination of chlorinated aliphatic hydrocarbons (CAHs)
by annealed and non-annealed nanoscale iron particles. The current study aims to resolve the uncertainties in recently published
work studying the effect of the annealing process on the reduction capability of nanoscale Fe particles. Comparison of the
normalized rate constants (m2/h/L) obtained for dechlorination reactions of trichloroethene (TCE) and cis-1,2-dichloroethene (cis-1,2-DCE) indicated that
annealing nanoscale Fe particles increases their reactivity ~30-fold. An electron transfer reaction mechanism for both types
of nanoscale particles was found to be responsible for CAH dechlorination, rather than a reduction reaction by activated H2 on the particle surface (i.e., hydrogenation, hydrogenolysis). Surface analysis of the particulate material using X-ray diffraction
(XRD) and transmission electron microscopy (TEM) together with surface area measurement by Brunauer, Emmett, Teller (BET)
indicate that the vacuum annealing process decreases the surface area and increases crystallinity. BET surface area analysis
recorded a decrease in nanoscale Fe particle surface area from 19.0 to 4.8 m2/g and crystallite dimensions inside the particle increased from 8.7 to 18.2 nm as a result of annealing. 相似文献