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211.
Al-Dirbashi OY Aboul-Enein HY Al-Odaib A Jacob M Rashed MS 《Biomedical chromatography : BMC》2006,20(4):365-368
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of ziprasidone (ZIP) in human plasma was developed. ZIP and N-methyl ziprasidone as internal standard (IS) were extracted from alkalinized plasma using tert- butyl methyl ether. Separation was performed isocratically on a C8 column with 90% acetonitrile containing 2 mmol/L ammonium acetate as a mobile phase with a total run time of 2.5 min. MS/MS transitions of m/z 413 --> 194 and m/z 427 --> 177 of the analyte and internal standard were used for quantification. Confirmatory ions of m/z 413 --> 177 and m/z 427 --> 180 were collected as well. The calibration curve based on peak-area ratio was linear up to at least 200 ng/mL with a detection limit of 0.1 ng/mL. The method showed satisfactory reproducibility with a coefficient of variation of less than 5%. The method was successfully applied to the analysis of ZIP in spiked human plasma. 相似文献
212.
UPLC-MS/MS determination of doxazosine in human plasma 总被引:2,自引:0,他引:2
Al-Dirbashi OY Aboul-Enein HY Jacob M Al-Qahtani K Rashed MS 《Analytical and bioanalytical chemistry》2006,385(8):1439-1443
A sensitive, selective and rapid method for the analysis of doxazosine (DOX) in human plasma based on ultra-performance liquid
chromatography tandem mass spectrometry (UPLC-MS/MS) is described. DOX and tamsulosin, used as an internal standard (IS),
were extracted by liquid-liquid extraction, and the chromatography was performed on a C18 UPLC column packed with 1.7 μm particles.
The total run time was 2 min. Detection was achieved by the multiple reaction monitoring of the following transitions: m/z 452→344 and m/z 409→228 for DOX and IS, respectively. Transitions of m/z 452→247 and m/z 409→271 were also collected for confirmation purposes. The calibration curve based on peak area ratio was linear up to at
least 100 ng ml−1, with a detection limit of 0.02 ng ml−1 (a signal-to-noise ratio of 3). The method showed satisfactory reproducibility, and the short-term stability of the analyte
was assessed. The method was successfully applied to the analysis of DOX in human plasma. 相似文献
213.
M. M. Britto Q. B. Cass I. C. S. F. Jardim C. A. Montanari H. Y. Aboul-Enein 《Chromatographia》2001,53(1-2):11-16
Summary The partition coefficients, logP
app
RPLC, for a series of propranolol analogues have been determined by reversed phase high performance liquid chromatography. The
hydrochloride salts and free base logP
app
RPLC show that charged and uncharged species can partition into the reversed phase. An extrathermodynamic relationship was found
for logP
app
RPLC measured in two different column stationary phases, C8 and PMOS, suggesting that the same set of compounds experience a similar
trend in these elution systems. The importance of using phosphate and/or MOPS buffer is due to the fact that the latter can
avoid ion-pairing partitioning, but the former does play the same role for PMOS column when the free base is considered. 相似文献
214.
Resolution of the enantiomers of (±)-econazole, (±)-miconazole, and (±)-sulconazole has been achieved on different normal-phase chiral amylose columns, Chiralpak AD, AS, and AR. The mobile phase used was hexane–2-propanol–diethylamine, 400:99:1 (v/v). The flow rates of the mobile phase used were 0.50 and 1.00 mL min–1. The α values for the resolved enantiomers of econazole, miconazole, and sulconazole on the chiral phases were in the range 1.63 to 1.04; the Rs values varied from 5.68 to 0.32. 相似文献
215.
J. F. van Staden R. -I. Stefan H. Y. Aboul-Enein 《Analytical and bioanalytical chemistry》2000,367(2):178-180
A new amperometric biosensor based on D-aminoacid oxidase is described for the assay of R-perindopril. R-perindopril can be determined in the 400–¶20 nmol/L concentration range; the detection limit is ¶10 nmol/L. The selectivity was checked with S-perindopril, D- and L-proline, and polyvinylpyrrolidone. The main interfering species was D-proline. An automated system for the assay of R-perindopril based on the concept of flow injection with an amperometric biosensor (based on D-aminoacid oxidase) as detector is also described. The system is suitable for the on-line monitoring of R-perindopril at a sampling rate of 72 samples/h, in the linear range: 100 nmol/L –20 nmol/L with an RSD better than 0.09% (n = 10). 相似文献
216.
H. Y. Aboul-Enein 《Accreditation and quality assurance》2000,5(7):286-287
Analytical chemists should focus their attention on establishing validated analytical methods for herbal pharmaceutical formulations.
Efforts should also be made to have the reference materials for herbal products both accessible and commercially available.
Received: 25 January 2000 / Accepted: 2 March 2000 相似文献
217.
Cyclodextrins as chiral selectors in capillary electrophoresis: a comparative study for the enantiomeric separation of some beta-agonists. 总被引:2,自引:0,他引:2
A comparative study for the enantiomeric separation of terbutaline, clenbuterol, salbutamol and dobutamine was performed by capillary electrophoresis using cyclodextrins and their derivatives as chiral selectors. Several parameters such as buffer composition and temperature were studied. Simple, fast and reliable enantioseparations were achieved for all drugs studied, especially when the isomerically pure sulfated beta-cyclodextrin derivatives were used as chiral selectors. 相似文献