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排序方式: 共有112条查询结果,搜索用时 15 毫秒
31.
32.
Dr. Manoj B. Gawande Dr. Anuj K. Rathi Prof. Dr. Paula S. Branco Dr. Isabel D. Nogueira Prof. Dr. Alexandre Velhinho Dr. Janhavi J. Shrikhande Dr. Utkarsha U. Indulkar Prof. Dr. Radha V. Jayaram Dr. C. Amjad A. Ghumman Dr. Nenad Bundaleski Prof. Orlando M. N. D. Teodoro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12628-12632
33.
34.
Vignaduzzo SE Maggio RM Castellano PM Kaufman TS 《Analytical and bioanalytical chemistry》2006,386(7-8):2239-2244
Two new analytical methods have been developed as convenient and useful alternatives for simultaneous determination of hydrochlorothiazide
(HCT) and propranolol hydrochloride (PRO) in pharmaceutical formulations. The methods are based on the first derivative of
ratio spectra (DRS) and on partial least squares (PLS) analysis of the ultraviolet absorption spectra of the samples in the
250–350-nm region. The methods were calibrated between 8.7 and 16.0 mg L−1 for HCT and between 14.0 and 51.5 mg L−1 for PRO. An asymmetric full-factorial design and wavelength selection (277–294 nm for HCT and 297–319 for PRO) were used
for the PLS method and signal intensities at 276 and 322 nm were used in the DRS method for HCT and PRO, respectively. Performance
characteristics of the analytical methods were evaluated by use of validation samples and both methods showed to be accurate
and precise, furnishing near quantitative analyte recoveries (100.4 and 99.3% for HCT and PRO by use of PLS) and relative
standard deviations below 2%. For PLS the lower limits of quantification were 0.37 and 0.66 mg L−1 for HCT and PRO, respectively, whereas for DRS they were 1.15 and 3.05 mg L−1 for HCT and PRO, respectively. The methods were used for quantification of HCT and PRO in synthetic mixtures and in two commercial
tablet preparations containing different proportions of the analytes. The results of the drug content assay and the tablet
dissolution test were in statistical agreement (p < 0.05) with those furnished by the official procedures of the USP 29. Preparation of dissolution profiles of the combined
tablet formulations was also performed with the aid of the proposed methods. The methods are easy to apply, use relatively
simple equipment, require minimum sample pre-treatment, enable high sample throughput, and generate less solvent waste than
other procedures.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
35.
Hector Rene Vega-Carrillo Arturo Ortíz-Hernandez Victor Martin Hernandez-Davila Berenice Hernández-Almaraz Teodoro Rivera Montalvo 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):537-540
Neutron spectrum and ambient dose equivalent has been measured around two 10 MV linear accelerators. Measurements were carried
out in Mevatron and Primus model linacs, both made by Siemens. Main differences between those models are the beam collimator
and the vault room. Here, Bonner sphere spectrometer with a passive thermal neutron detector has been utilized to measure
the neutron spectrum inside the vault. Using an active detector the neutron spectrum was measured at the vault’s door of both
accelerators. With a neutron area monitor the dose equivalent was measured by the door at both vault doors. Neutron strength,
total fluence rate and ambient dose equivalent were compared, from this was found that shielding conditions are better in
the Primus model. 相似文献
36.
The reaction of N-tosyltryptamines with thioortho esters, leading to 1-thiosubstituted tetrahydro-beta-carbolines under modified Pictet-Spengler conditions, is described. The 1-heterosubstituted beta-carbolines furnished 1-substituted beta-carbolines upon reaction with Grignard reagents and silyl derivatives under Lewis acid promotion. [reaction: see text] 相似文献
37.
Silvana E. Vignaduzzo Luciana Vera-Candioti Patricia M. Castellano H��ctor C. Goicoechea Teodoro S. Kaufman 《Chromatographia》2011,74(7-8):609-617
A capillary zone electrophoresis method for the simultaneous determination of pridinol mesylate (PRI) and meloxicam (MEL) employing epinastine hydrochloride and piroxicam as internal standards, was developed and optimized employing experimental design and response surface methodologies. The separation was optimally achieved in less than 2 min at 30 kV in an uncoated fused-silica capillary (41.4 cm × 75 ??m I.D.), employing an 18 mmol L?1 sodium phosphate buffer solution (pH 5.90) at 25 °C. Samples were injected in hydrodynamic mode (50 mbar, 5 s) and the analytes were spectrophotometrically detected at 200 nm. Method robustness was demonstrated by ANOVA of determinations performed under conditions slightly different from the optimum. The method was validated regarding separation selectivity (peak purity factors > 0.99), linearity and range (PRI = 17.6?C31.4 mg L?1; MEL = 66.5?C122.5 mg L?1), accuracy (PRI = 100.2?C101.9%; MEL = 98.9?C100.7%) and precision. The RSD values obtained were ??1.3% for injection repeatability and ??1.9% for intra-day precision. The limits of detection (1.0 and 0.9 mg L?1) and quantification (3.3 and 16.5 mg L?1) of PRI and MEL, respectively, were also determined. The method was successfully applied to the determination of both drugs in three brands of tablet formulations. No statistically significant differences were observed when these results were compared with those of a RP-HPLC method. 相似文献
38.
Saviour A. Umoren Mauro J. Banera Teodoro Alonso-Garcia Claudio A. Gervasi Maria V. Mirífico 《Cellulose (London, England)》2013,20(5):2529-2545
The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild steel in 0.1 M HCl was investigated by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopy measurements, scanning electron microscopy, and UV–visible analysis. The polymer was found to inhibit corrosion even at a very low concentration. Inhibition efficiency increases with a rise in temperature up to 96 % at 60 °C and then drops to 93 % at 70 °C, while it slightly increases with an increase in chitosan concentration. Polarization curves indicate that chitosan functions as a mixed inhibitor, affecting both cathodic and anodic partial reactions. Impedance results indicate that chitosan was adsorbed on the metal/solution interface. Adsorption of chitosan at the mild steel surface is found to be in agreement with Langmuir adsorption isotherm model. Chemical adsorption is the proposed mechanism for corrosion inhibition considering the trend of protection efficiency with temperature. Calculated kinetic and thermodynamic parameters corroborate the proposed mechanism. 相似文献
39.
40.
Marc Alexandre Duarte Gigonzac Lilian Souza Teodoro Lysa Bernardes Minasi Thaís Cidália Vieira Aparecido Divino da Cruz 《Electrophoresis》2016,37(23-24):3076-3078
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability. The most common etiology of the syndrome is expansion and methylation of a CGG trinucleotide at chromosome region Xq27.3 involving FMR1 (fragile X mental retardation 1 gene). This disorder is commonly underdiagnosed in children and adolescents, given the high clinical variability. In Brazil, molecular diagnosis of FXS by CE does not exist in the public health system. The current standard for separation and identification of DNA fragment sizes is 50 cm CE, which is uncommon in public genotyping laboratories. This study describes the standardization of 36 cm CE for fragment analysis of samples from patients with intellectual disability suggestive of FXS. Genomic dsDNA was isolated from patients and amplified by PCR using the FMR1 AmplideX® Kit. It was then possible to detect changes in repeat length of FMR1, such as full mutation and premutation. Thus, the proposed standardization proved to be effective for the diagnosis of FXS, permitting suitable genetic counseling for families. Inclusion of molecular testing such as this in the Brazilian public health service bridges the gap between available technologies and effective diagnosis, universalizing access to genetic testing in central Brazil. 相似文献