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191.
Abstract

Chemical composition of the headspace volatiles and essential oils isolated from different parts of Ferulago sylvatica was determined by GC and GC/MS analyses. The results showed that headspace volatiles obtained from the aerial parts and roots were similar regarding the number of identified compounds and main components. However, essential oils obtained from different plant organs showed significant differences in chemical composition. Myrcene was the most abundant component of the inflorescences and shoots volatiles, while α-pinene make up over 50% of the root volatiles. Only three components were identified in the root essential oil with 2,3,6-trimethyl benzaldehyde (92.7%) as the main component. In the shoots sample the terpenoid fractions represented 56% of the oil, unevenly distributed between monoterpenoids and sesquiterpenoids with germacrene D (32.5%) recognized as the main constituent. On the other hand, more than 94% of the inflorescences oils were monoterpenoids with myrcene as the most abundant contributor (29.2%).  相似文献   
192.
Herbal teas are an important part of traditional medicine in Serbia. The objective of the present study was to determine the activity concentrations of 40K and 137Cs in herbal tea, using the gamma spectroscopy method. The samples were collected during the period 2011–2012 in three mountain regions in Western and Central Serbia. The activity concentrations of 40K and 137Cs were found to be in the range of 130–1160 and 0.7–124 Bq kg?1, respectively. The average annual effective dose equivalents from ingestion of 40K and 137Cs for an adult person consuming one cup of herbal tea daily were found to be 588.4–5250.2 nSv for 40K and 4.0–706.1 nSv for 137Cs. Our investigation showed that the herbal teas originating from Maljen, Zlatibor and Tara mountains are radiologically safe for human consumption.  相似文献   
193.
194.
Two series of 3-(4-substituted benzyl)-5-ethyl-5-phenyl- and 3-(4-substituted benzyl)-5,5-diphenylhydantoins were synthesized and their UV absorption spectra were recorded in the region 200–400 nm in selected solvents of different polarity. The effects of solvent dipolarity/polarizability and solvent/solute hydrogen bonding interactions on the spectral shifts were analyzed by means of the linear solvation energy relationship (LSER) methodology of Kamlet and Taft. The quantitative relationships between hydrogen bonding interactions and the lipophilicity and blood-brain permeation of the studied compounds were discussed. Satisfactory linear dependences were obtained for moderate electron-donating and electron-withdrawing substituents at the benzyl moiety, while the strong electron-withdrawing substituent (NO2) significantly modifies the solvation characteristics of the molecule. The paper clearly demonstrates how the solvatochromic comparison method may be applied to estimate the contributions of various modes of solvation to the pharmaceutically relevant properties of these newly synthetized hydantoin derivatives.  相似文献   
195.
The results of studying inhibitory effect of streptomycin on the modified Berthelot reaction were presented in this paper and a new kinetic method for determining streptomycin in pharmaceutical preparations and human urine was developed on the basis of the obtained results. The rates of catalytic and catalytic‐inhibitory reaction were monitored at 700 nm (t=25±0.1°C) using UV/vis spectrophotometer. By analyzing the spectra and experimental dependences of the catalytic and catalytic‐inhibitory reaction rates on the reactant concentrations, it was noticed that streptomycin attacked nitroprusside and hypochlorite causing the inhibition of the production of 2,2′‐dicarboxylindophenol. According to this effect, an analytical decrease for determination of urea by modified Berthelot reaction appeared in the presence of small amounts of streptomycin. Beer's law was obeyed in the interval of streptomycin sulfate concentration from 18.2 to 182 µg·mL?1. The detection limit calculated by two methods was obtained at 11.75 µg·mL?1 and 8.54 µg·mL?1. The relative standard deviation of 0.55%–8.83% and the recovery of 109.10% were determined. The obtained results were validated using the referent HPLC method.  相似文献   
196.
In this study we define the optimal conditions for ultrasound-assisted extraction of bioactive polyphenols from S. raeseri aerial parts using response surface methodology. The influence of ethanol concentration (10–90%), extraction temperature (20–80 °C), extraction time (10–60 min), and solid-to-solvent ratio (1:10–1:50) on total phenolic content as well as on content of individual flavonoids, and hypolaetin and isoscutellarein derivatives was studied. For the experimental design, a central composite design was chosen. In the obtained extracts, the following ranges of targeted compounds were detected: total phenol from 19.32 to 47.23 mg GAE/g dw, HYP from 1.05 to 11.46 mg/g dw, ISC 1 from 0.68 to 10.68 mg/g dw, and ISC 2 from 0.74 to 15.56 mg/g dw. The optimal extraction conditions were set as: ethanol concentration of 65%, extraction time of 50 min, extraction temperature of 63 °C, and solid-to-solvent ratio of 1:40. Contents of TP, HYP, ISC 1, and ISC 2 in optimal extracts were 47.11 mg GAE/g dw, 11.73 mg/g dw, 9.54 mg/g dw, and 15.40 mg/g dw, respectively. Experimentally set values were in good agreement with those predicted by the response surface methodology model, indicating suitability of the used model, as well as the success of response surface methodology in optimizing the conditions of the extraction.  相似文献   
197.
Multifractal (MF) approach was applied for the analysis of ultraviolet/visible (UV/VIS) spectra as an independent confirmation of the diagnostic efficacy of UV/VIS spectral analysis of intraperitoneal fluids, ascites, taken from patients with a known clinical diagnosis. Recently, it was reported that from UV/VIS spectra differentiation of malignant from benign ascites is possible. Here, it was shown that by using MF analysis of UV/VIS spectra, the objective classification of UV/VIS spectra is possible. The applicability of UV/VIS analysis and MF classification of spectra were evaluated on N=68 cases, of which M=64 and B=4 were clinically confirmed as malignant and benign, respectively. The overall diagnostic efficacy was 89.71% when using on-line analysis of UV/VIS spectra (61 out of 68 samples were positively recognized: 58 malignant and 3 benign), and even 95.59% by using off-line MF classsification (65 out of 68 samples were classified correctly: 63 malignant and 2 benign). It can be inferred that UV/VIS spectral analysis of ascites, combined with MF analysis, could be suggested as a successful and safe screening method in the evaluation of intraperitoneal fluids.  相似文献   
198.
The Fischer indolization afforded the title compound C31H25N3·C2H5OH as the major product in the reaction of 1,5-di(p-tolyl)pentane-1,3,5-trione with phenylhydrazine hydrochloride in ethanol. The structure assignment of this novel pyrazolylindole derivative is based on the data of elemental analysis, IR, 1H NMR, and 13C NMR spectroscopy. The structure is also confirmed by means of X-ray crystallography. The molecule crystallizes in the orthorhombic space group P 212121, with a = 10.298(2), b = 14.984(5), c = 18.133(3) A, Z = 8, V = 2798.0(12) A3. The absolute structure has been determined. The ethanol molecule forms intermolecular hydrogen bonds with the pyrazole and indole nitrogen atoms.  相似文献   
199.
The structural changes of aniline oligomers and polyaniline, associated with oxidation of aniline with ammonium peroxydisulfate in aqueous solutions without any added acid, were studied. The reaction was quenched at various times and the films deposited on silicon windows have been studied in detail by Raman spectroscopy, at excitation wavelengths 633 and 514 nm. The presence of substituted phenazine structural units, in addition to ordinary benzenoid, quinonoid, and semiquinonoid structures, has been proved by the appearance of characteristic Raman bands at 1645–1630, 1420–1400, 1380–1365, ∼575, and ∼415 cm−1. The remarkable differences of the Raman spectra of oligoanilines, precipitated in the first phase of oxidative polymerization, and polyaniline nanotubes and nanorods, formed in the second stage of reaction, are discussed. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
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