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排序方式: 共有137条查询结果,搜索用时 31 毫秒
131.
Saied Saeed Hosseiny Davarani Saeed Nojavan Roghayeh Asadi Mohammad Hossein Banitaba 《Journal of separation science》2013,36(14):2315-2322
In this study, a platinum wire coated with poly(3,4‐ethylenedioxythiophen) was used as an electro‐assisted solid‐phase microextraction fiber for the quantification of tricyclic antidepressant drugs in biological samples by coupling to GC employing a flame ionization detector. In this study, an electric field increased the extraction rate and recovery. The fiber used as a solid phase was synthesized by the electropolymerization of 3,4‐ethylenedioxythiophen monomers onto a platinum wire. The ability of this fiber to extract imipramine, desipramine, and clomipramine by using the electro‐assisted solid‐phase microextraction technique was evaluated. The effect of various parameters that influence the extraction efficiency, which include solution temperature, extraction time, stirring rate, ionic strength, time and temperature of desorption, and thickness of the fiber, was optimized. Under optimized conditions, the linear ranges and regression coefficients of calibration curves were in the range of 0.5–250 and 0.990–0.998 ng/mL, respectively. Detection limits were in the range of 0.15–0.45 ng/mL. Finally, this method was applied to the determination of drugs in urine and wastewater samples and recoveries were 4.8–108.9%. 相似文献
132.
Application of a new fiber coating based on electrochemically reduced graphene oxide for the cold‐fiber headspace solid‐phase microextraction of tricyclic antidepressants
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Mohammad Hossein Banitaba Saied Saeed Hosseiny Davarani Hamid Ahmar Siyavash Kazemi Movahed 《Journal of separation science》2014,37(9-10):1162-1169
A new fiber based on the electrochemical reduction of graphene oxide was prepared on a copper wire for solid‐phase microextraction (SPME) applications. The prepared fiber was used for the SPME and gas chromatographic analysis of tricyclic antidepressants (TCADs), including amitriptyline, trimipramine, and clomipramine. The feasibility of direct‐immersion and headspace modes of SPME for the determination of TCADs was studied. The effects of four parameters including pH, salt content, extraction temperature with and without cooling the fiber, and extraction time were investigated. The comparison showed that headspace cold fiber SPME results in the best outcome for the extraction of TCADs. Under the optimized conditions of this mode, the calibration curves were linear between 2.0 and 500 ng/mL and the detection limits were between 0.30 and 0.53 ng/mL. The intraday and interday RSDs obtained at 20 ng/mL (n = 5), using a single fiber, were 5.5–9.0 and 7.5–9.8, respectively. The fiber to fiber repeatability (n = 4), expressed as the RSD, was between 12.8 and 13.2% at a 20 ng/mL concentration level. The method was successfully applied to the analysis of TCADs in plasma samples showing recoveries from 73 to 96%. 相似文献
133.
A new method for the CE separation of nine tricyclic antidepressants (TCAs), viz. amitriptyline, clomipramine, desipramine, doxepin, fluphenazine, imipramine, nortriptyline, promazine, and thioridazine, is described. The capillary was statically coated with a layer of poly(N,N-dimethylacrylamide) (PDMA) to suppress the EOF, and beta-CD was used as an additive in the BGE solution. The optimal resolution of nine TCAs was obtained by using a 1% v/v PDMA-coated capillary and a BGE solution of 50 mM sodium phosphate buffer (pH 3.0) containing 0.5 mM beta-CD. Efficiencies were typically >10(5 )plates/m. Complete separation of nine TCAs could be achieved in about 28 min; the two diastereomers of doxepin and the two enantiomers of thioridazine could also be separated. The RSD values of migration time and peak area of the TCAs were in the ranges 0.5-0.8 and 3.3-4.9% (n = 10), respectively. In combination with a suitable sample clean-up technique, such as hollow fiber-based liquid phase microextraction (HF-LPME), the polymer-coated capillary can be employed for the CE-UV analysis of TCAs in human plasma. 相似文献
134.
Lee XP Hasegawa C Kumazawa T Shinmen N Shoji Y Seno H Sato K 《Journal of separation science》2008,31(12):2265-2271
A method for the simultaneous extraction of four tricyclic antidepressants from human plasma samples using pipette tip SPE with MonoTip C(18) tips is presented. Human plasma (0.1 mL) containing four tricyclic antidepressants (amitriptyline, amoxapine, imipramine, and trimipramine) and an internal standard (IS), protriptyline, was mixed with 0.4 mL of distilled water and 100 microL 1 M NaOH solution. After centrifugation of the mixture, the supernatant was extracted to the C(18) phase of the tip by 20 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained in the tip were eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was directly injected into a gas chromatograph injector and detected by a mass spectrometer with SIM in the positive-ion electron impact mode. Recovery of the four antidepressants and IS spiked into human plasma was 80.2-92.1%. The regression equations for the four antidepressants showed excellent linearity in the range of 0.2-40 ng/0.1 mL. LODs and LOQs for the four drugs were 0.05-0.2 ng/0.1 mL and 0.2-0.5 ng/0.1 mL, respectively. Intra- and interday CVs for the four drugs in plasma were no greater than 9.5%. 相似文献
135.
Cell-based screening systems for pharmaceuticals are desired over molecular biosensing systems because of the information
they provide on toxicity and bioavailability. However, the majority of sensing systems developed are molecular biosensing
type screening systems and cannot be easily adapted to cell-based screening. In this study, we demonstrate that protein-based
molecular sensing systems that employ a fluorescent protein as a signal transducer are amenable to cell-based sensing by expressing
the protein molecular sensing system in the cell and employing these cells for screening of desired molecules. To achieve
this, we expressed a molecular sensing system based on the fusion protein of calmodulin (CaM) and enhanced green fluorescent
protein (EGFP) in bacterial cells, and utilized these cells for the screening of CaM antagonists. In the presence of Ca2+, CaM undergoes a conformational change exposing a hydrophobic pocket that interacts with CaM-binding proteins, peptides,
and drugs. This conformational change induced in CaM leads to a change in the microenvironment of EGFP, resulting in a change
in its fluorescence intensity. The observed change in fluorescence intensity of EGFP can be correlated to the concentration
of the analyte present in the sample. Dose-response curves for various tricyclic antidepressants were generated using cells
containing CaM-EGFP fusion protein. Additionally, we demonstrate the versatility of our system for studying protein-protein
interactions by using cells to study the binding of a peptide to CaM. The study showed that the CaM-EGFP fusion protein within
the intact cells responds similarly to that of the isolated fusion protein, hence eliminating the need for any isolation and
purification steps. We have demonstrated that this system can be used for the rapid screening of various CaM antagonists that
are potential antipsychotic drugs. 相似文献
136.
Cantú MD Toso DR Lacerda CA Lanças FM Carrilho E Queiroz ME 《Analytical and bioanalytical chemistry》2006,386(2):256-263
Simple, sensitive, and reproducible off-line solid-phase microextraction and liquid chromatography (SPME/LC) methods are described
for the determination of seven anticonvulsants and tricyclic antidepressants in human plasma. Factorial design and simplex
methodology were applied in the optimization of the SPME procedure for tricyclic antidepressants analyses. Important factors
in the SPME efficiency are discussed, such as the fiber coatings (both lab-made and commercial), extraction time, pH, ionic
strength, influence of plasma proteins, and desorption conditions. The development of the lab-made fiber coatings, namely,
octadecylsilane, aminosilane, and polyurethane, are further described and applied to anticonvulsants analyses. The investigated
plasmatic range for the evaluated anticonvulsants, using CW-TPR fiber, were the following: phenylethylmalonamide (3.00–40.0 μg
mL−1), phenobarbital (5.00–40.0 μg mL−1), primidone (3.00–40.0 μg mL−1), carbamazepine and carbamazepine-epoxide (2.00–24.0 μg mL−1), phenytoin (2.00–40.0 μg mL−1), and lamotrigine (0.50–12.0 μg mL−1). The antidepressants’ linear plasmatic concentration ranged from 75.0 to 500 ng mL−1 for imipramine, amitriptyline, and desipramine, and from 50.0 to 500 ng mL−1 for nortriptyline, being in all cases, the limit of quantification represented by the lowest value. The precision (interassays)
for all investigated drugs in plasma sample spiked with different concentrations of each analyte and submitted to the described
procedures were lower than 15%. The off-line SPME/LC methodologies developed allow anticonvulsants and antidepressants analyses
from therapeutic to toxic levels for therapeutic drug monitoring. 相似文献
137.
Dr. Fabio Buonsenso Dr. Marta Colombo Dr. Andrea Marchesi Francesca Romana Mammone Prof. Francesco Sannicolò Dr. Roberto Cirilli Prof. Marco Pierini 《European journal of organic chemistry》2023,26(33):e202300568
An experimental and theoretical study was carried out to analyze the configurational lability possessed by some of the most common drugs endowed with a central non-planar seven-membered cycloheptadiene ring, which confers chirality to these compounds. In fact, the absence of planarity allows the existence of two enantiomeric species that can interconvert thanks to a ring overturning mechanism. The energy barrier that opposes the inversion of the chiral tricyclic scaffold characterizing such species, which is strongly dependent on the presence of appropriate substituents on the two external cycles, has been investigated through Dynamic-HPLC and off-column racemization techniques, as well as through assessments based on molecular modelling approaches. Interesting indications were obtained by making targeted structural changes to allow accurate control of the stereolability characterizing the tricyclic framework. 相似文献