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71.
Determination of citalopram by capillary electrophoresis is described. Compounds were separated at 28 kV in 75 μm i.d. fused silica capillary tubing (total length 85 cm, effective length 65 cm) with 10 mM borate buffer, pH 8.5, containing 10% (v/v) methanol as running buffer. Citalopram and propylparaben (IS) appeared at 3.5 and 5.5 min, respectively. Repeatable linear results were obtained. The limits of detection and quantification were 5.73 × 10−6 and 1.72 × 10−5 M, respectively. When citalopram was determined in a pharmaceutical tablet by capillary electrophoresis and by a UV-spectrophotometric method differences between the results were not significant. The citalopram content of tablets was 100.8 ± 2.95% of the label claim. The amount found in serum was 26.7 ± 0.1% of the free drug, indicating that 73.3% of the drug was bound to protein. 相似文献
72.
The application of multivariate curve resolution with alternating least squares (MCR-ALS) methods to second-order data from capillary electrophoresis with diode array detector (CE-DAD) is reported. Initial qualitative solutions obtained by evolving factor analysis (EFA) and pure-variable detection method can be further optimized by a simultaneous analysis of multiple electrophoresis run data with ALS regression. While unknown samples are analyzed simultaneously against the corresponding standards in different composition ratios, the exact amounts of common components in different CE runs can be determined by the traditional calibration curve method, and quantification can thus be achieved. The above methods are applied to the determination of the components in compound reserpine tablets in overlapping peaks from CE. The quantification results are compared with those of the first derivative of the electropherogram method and artificial neural network (ANN) method. 相似文献
73.
One titrimetric and two spectrophotometric methods, which are simple, sensitive and rapid, are described for the assay of
lamivudine in bulk drug and in tablet dosage forms using potassium iodate and two dyes, methyl orange and indigocarmine, as
reagents. In titrimetry, an aqueous solution of lamivudine is titrated directly with iodate in an acidic medium, and in the
presence of an excess of bromide using methyl orange as an indicator. After the decoloration of the red color of methyl orange,
the residual bromine is titrated iodometrically to a starch endpoint. Spectrophotometric methods involve the addition of a
known excess of iodate in an acidic medium and in the presence of an excess of bromide followed by the determination of residual
bromine by the reaction with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (method A), or
indigo carmine and measuring the absorbance at 610 nm (method B). In all methods, the amount of iodate which reacted corresponds
to the amount of lamivudine content. The titrimetric method is applicable over the 1.5–8.0 mg range. The systems obey Beer’s
law for 0.5–5.0 μg/mL (method A) and 1.25–12.5 μg/mL (method B). The calculated apparent molar absorptivity values are found
to be 3.3 × 104 and 9.3 × 103 L mol−1 cm−1, for method A and method B, respectively, and the corresponding Sandell sensitivity values are 6.94 and 24.62 ng/cm2. The limits of detection and quantification are also reported for both spectrophotometric methods. Intra-and interday precision
and accuracy for the developed methods have been evaluated. The methods were successfully applied to the assay of lamivudine
in tablet form and the results were compared with those of a reference method by applying the Student’s t-test and F-test.
No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained
by recovery experiments using the standard addition technique.
The text was submitted by the authors in English. 相似文献
74.
The cyclic voltammogram of the anti-coagulant drug warfarin sodium at the hanging mercury drop electrode exhibited a well-defined single two-electron irreversible peak over the pH range 4-7, which may be attributed to the reduction of the CO double bond of the drug molecule. Based on the interfacial adsorptive character of the drug onto the mercury electrode surface, a square-wave cathodic stripping procedure was optimized for its trace determination. The calibration plot was linear over the concentration range of 5×10−9 to 4×10−7 M warfarin sodium in Britton-Robinson (B-R) buffer of pH 5, with limits of detection and quantitation of 6.5×10−10 and 2.1×10−9 M warfarin sodium, respectively. The proposed procedure was successfully applied for assay of warfarin sodium in its pharmaceutical formulation “hemofarin tablets”, human serum and urine without the necessity for sample pretreatment or time-consuming extraction or evaporation steps, prior to assay of the drug. Limits of detection of 1.1×10−9 and 1.3×10−8 M warfarin sodium were achieved, while limits of quanitation of 3.7×10−9 and 4.3×10−8 M warfarin sodium were estimated in human serum and urine, respectively. The pharmacokinetic profiles of the drug were studied and the estimated pharmacokinetic parameters were favorably compared with those reported in literature. 相似文献
75.
76.
Goenaga-Infante H Sturgeon R Turner J Hearn R Sargent M Maxwell P Yang L Barzev A Pedrero Z Cámara C Díaz Huerta V Fernández Sánchez ML Sanz-Medel A Emese K Fodor P Wolf W Goldschmidt R Vacchina V Szpunar J Valiente L Huertas R Labarraque G Davis C Zeisler R Turk G Rizzio E Mackay LG Myors RB Saxby DL Askew S Chao W Jun W 《Analytical and bioanalytical chemistry》2008,390(2):629-642
Results of an international intercomparison study (CCQM-P86) to assess the analytical capabilities of national metrology institutes
(NMIs) and selected expert laboratories worldwide to accurately quantitate the mass fraction of selenomethionine (SeMet) and
total Se in pharmaceutical tablets of selenised-yeast supplements (produced by Pharma Nord, Denmark) are presented. The study,
jointly coordinated by LGC Ltd., UK, and the Institute for National Measurement Standards, National Research Council of Canada
(NRCC), was conducted under the auspices of the Comité Consultatif pour la Quantité de Matière (CCQM) Inorganic Analysis Working
Group and involved 15 laboratories (from 12 countries), of which ten were NMIs. Apart from a protocol for determination of
moisture content and the provision of the certified reference material (CRM) SELM-1 to be used as the quality control sample,
no sample preparation/extraction method was prescribed. A variety of approaches was thus used, including single-step and multiple-step
enzymatic hydrolysis, enzymatic probe sonication and hydrolysis with methanesulfonic acid for SeMet, as well as microwave-assisted
acid digestion and enzymatic probe sonication for total Se. For total Se, detection techniques included inductively coupled
plasma (ICP) mass spectrometry (MS) with external calibration, standard additions or isotope dilution MS (IDMS), inductively
coupled plasma optical emission spectrometry , flame atomic absorption spectrometry and instrumental neutron activation analysis.
For determination of SeMet in the tablets, five NMIs and three academic/institute laboratories (of a total of five) relied
upon measurements using IDMS. For species-specific IDMS measurements, an isotopically enriched standard of SeMet (76Se-enriched SeMet) was made available. A novel aspect of this study relies on the approach used to distinguish any errors
which arise during analysis of a SeMet calibration solution from those which occur during analysis of the matrix. To help
those participants undertaking SeMet analysis to do this, a blind sample in the form of a standard solution of natural abundance
SeMet in 0.1 M HCl (with an expected value of 956 mg kg−1 SeMet) was provided. Both high-performance liquid chromatography (HPLC)–ICP-MS or gas chromatography (GC)–ICP-MS and GC-MS
techniques were used for quantitation of SeMet. Several advances in analytical methods for determination of SeMet were identified,
including the combined use of double IDMS with HPLC-ICP-MS following extraction with methanesulfonic acid and simplified two-step
enzymatic hydrolysis with protease/lipase/driselase followed by HPLC-ICP-IDMS, both using a species-specific IDMS approach.
Overall, satisfactory agreement amongst participants was achieved; results averaged 337.6 mg kg−1 (n = 13, with a standard deviation of 9.7 mg kg−1) and 561.5 mg kg−1(n = 11, with a standard deviation of 44.3 mg kg−1) with median values of 337.6 and 575.0 mg kg−1 for total Se and SeMet, respectively. Recovery of SeMet from SELM-1 averaged 95.0% (n = 9). The ability of NMIs and expert laboratories worldwide to deliver accurate results for total Se and SeMet in such materials
(selensied-yeast tablets containing approximately 300 mg kg−1 Se) with 10% expanded uncertainty was demonstrated. The problems addressed in achieving accurate quantitation of SeMet in
this product are representative of those encountered with a wide range of organometallic species in a number of common matrices.
Figure Looking into the quantitative speciation of selenium in pharmaceutical supplements Photo courtesy of LGC. 相似文献
77.
Nafisur Rahman Yasmin Ahmad Syed Najmul Hejaz Azmi Saba A. J. Sulaiman 《中国化学会会志》2008,55(6):1357-1366
The main aim of this work is to develop and validate a spectrophotometric method for the determination of nicorandil in commercial tablets. The method is based on the reduction of the nitroxy ethyl group of nicorandil into carbonyl compound and nitrite ion by NH4Cl and Zn dust. The nitrite ion thus formed reacts with potassium iodide and starch in dilute HCl medium to form a blue product, which absorbs maximally at 550 nm. Beer's law is obeyed in the concentration range 0.4‐4.0 μg mL?1 with molar absorptivity of 7.92 × 104L mol?1 cm?1. The detection limit is 0.017 μg mL?1. The reaction conditions are optimized and validated as per the International Conference on Harmonisation guidelines (USA). The proposed method has been applied successfully for the determination of nicorandil in commercial tablets. The results of analyses are compared statistically with those of the author's spectrophotometric method, which confirmed that there is no significant difference between the methods compared. 相似文献
78.
Simultaneous determination of kaempferol,quercetin, mangiferin,gallic acid,p‐hydroxybenzoic acid and chlorpheniramine maleate in rat plasma after oral administration of Mang‐Guo‐Zhi‐Ke tablets by UHPLC‐MS/MS and its application to pharmacokinetics 下载免费PDF全文
《Biomedical chromatography : BMC》2018,32(4)
Mang‐Guo‐Zhi‐Ke tablets (MGZKTs) is an effective Chinese patent medicine. It contains mango leaf extract as the main raw material and the antihistamine drug, chlorpheniramine maleate is included in the formulation. However, its pharmacokinetic effect is rarely reported. A highly sensitive, reliable and rapid high‐throughput method using ultra‐high‐performance liquid chromatography with tandem mass spectrometry (UHPLC‐MS/MS) was used to simultaneously determine kaempferol, quercetin, mangiferin, p‐hydroxybenzoic acid, gallic acid and chlorpheniramine maleate in rat plasma after oral administration of MGZKTs. The method was successfully developed and fully validated to investigate the pharmacokinetics of MGZKTs. Chloramphenicol and clarithromycin were used as internal standards (IS). A practicable protein precipitation procedure with methanol was adopted for sample preparation. The samples were separated on an Acquity UHPLC Syncronis C18 column (100 × 2.1 mm, 1.7 μm) using 0.1% formic acid–acetonitrile as the mobile phase. The flow rate was set at 0.4 mL/min. The obtained calibration curves were linear in the concentration range of ~1–1000 ng/mL for plasma (r > 0.99). Method validation results met the criteria reported in the US Food and Drug Administration guidelines. Quercetin, p‐hydroxybenzoic acid and kaempferol were absorbed rapidly and reached the peak concentration between 0.16 and 0.25 h. This validated that the UHPLC‐MS/MS method was successfully applied to study the pharmacokinetic parameters of the six compounds in rat plasma after oral administration of MGZKTs. This evidence will be useful for the clinical rational use of Mang‐Guo‐Zhi‐Ke tablets. 相似文献
79.
Xinyu Zhao Yan Wang Lu Zheng Chengpeng Sun Chao Wang Haijian Cong 《Natural product research》2018,32(17):2031-2036
Shuanghua Baihe tablet is a traditional Chinese patent medicine which showed special advantages in the treatment of recurrent aphthous stomatitis. Scientists have improved and implemented the LC-MS/MS method, which is specific and sensitive, for comparative pharmacokinetics study of five alkaloids, including palmatine, berberine, epiberberine, jatrorrhizine and coptisine in rat plasma after oral administration of Rhizoma Coptidis extract and Shuanghua Baihe tablets. The results showed that Shuanghua Baihe tablets could promote the absorption of these five alkaloids and improved their bioavailability compared with R. Coptidis extract. To further investigate the related mechanism, everted intestinal sac model in vitro was used to indicate that alteration of in vivo pharmacokinetics of five alkaloids could be attributed to, at least in part, the absorption changes by coadministration of other herbs. These discoveries served as a theoretical basis for clinical use of Shuanghua Baihe tables. 相似文献
80.