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排序方式: 共有66条查询结果,搜索用时 15 毫秒
41.
de Castro A Ramírez Fernandez Mdel M Laloup M Samyn N De Boeck G Wood M Maes V López-Rivadulla M 《Journal of chromatography. A》2007,1160(1-2):3-12
A rapid, sensitive and fully automated on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method was developed and validated for the direct analysis of 14 antidepressants and their metabolites in plasma. Integration of the sample extraction and LC separation into a single system permitted direct injection of the plasma without prior sample pre-treatment. The applied gradient ensured the elution of all the examined drugs within 14 min and produced chromatographic peaks of acceptable symmetry. The total process time was 20 min and only 50 microL of plasma was required. Selectivity of the method was achieved by a combination of retention time and two precursor-product ion transitions for the non-deuterated compounds. The use of SPE was demonstrated to be highly effective and led to significant decreases in the interferences present in the matrix. Extraction was found to be both reproducible and efficient with recoveries >99% for all the analytes. The method showed excellent intra-assay and inter-assay precision (relative standard deviation (RSD) and bias <20%) for quality control (QC) samples spiked at a concentration of 40, 200 and 800 microg/L and the r2>0.99 over the range investigated (10-1000 microg/L). Limits of quantification (LOQs) were estimated to be 10 microg/L. Furthermore, the processed samples were demonstrated to be stable for at least 48 h, except for clomipramine and norclomipramine, where a slight negative trend was observed, but did not compromise the quantification. The method was subsequently applied to authentic samples previously screened by a routine HPLC method with diode array detection (DAD). 相似文献
42.
Laloup M Fernandez Mdel M Wood M Maes V De Boeck G Vanbeckevoort Y Samyn N 《Analytical and bioanalytical chemistry》2007,388(7):1545-1556
Sedative agents are used to facilitate sexual assault due to their ability to render the victim passive, submissive and unable to resist. The primary pharmacological effect of the benzodiazepine tetrazepam is muscle relaxation, whereas the benzodiazepine diazepam acts on the central nervous system (CNS) exerting mainly sedation effects. Therefore, contrary to tetrazepam, diazepam is an often-abused drug, which can potentially be used as a date-rape drug. In this study, we describe the detection of low amounts of diazepam in Myolastan (Sanofi-Synthelabo S.A., Brussels, Belgium) and Epsipam (Will-Pharma, Wavre, Belgium) 50 mg tablet preparations by LC-MS-MS, GC-FID and HPLC-DAD. Considering the important forensic implication of this finding, a study was conducted with volunteers receiving a single or repeated dosage of Myolastan. Urine, hair and preserved oral fluid samples were analysed using a previously described sensitive and specific LC-MS-MS detection method allowing for the simultaneous quantification of tetrazepam, diazepam, nordiazepam, oxazepam and temazepam. This study demonstrates that diazepam can be observed in urine samples even after a single dose of Myolastan. In addition, maintaining therapy for 1 week results in the detection of both diazepam and nordiazepam in urine samples and of diazepam in the first hair segment. Importantly, comparing urine and hair samples after a single intake of diazepam versus the single and 1 week administration of Myolastan shows that the possible metabolic conversion of tetrazepam to diazepam is a more plausible explanation for the detection of diazepam in biological samples after the intake of Myolastan. As such, these results reveal that the presence of diazepam and/or nordiazepam in biological samples from alleged drug-facilitated assault cases should be interpreted with care. 相似文献
43.
Fábio Cristiano Angonesi Brod Jeroen P. van Dijk Marleen M. Voorhuijzen Andréia Zilio Dinon Luis Henrique S. Guimarães Ingrid M. J. Scholtens Ana Carolina Maisonnave Arisi Esther J. Kok 《Analytical and bioanalytical chemistry》2014,406(5):1397-1410
The ever-increasing production of genetically modified crops generates a demand for high-throughput DNA-based methods for the enforcement of genetically modified organisms (GMO) labelling requirements. The application of standard real-time PCR will become increasingly costly with the growth of the number of GMOs that is potentially present in an individual sample. The present work presents the results of an innovative approach in genetically modified crops analysis by DNA based methods, which is the use of a microfluidic dynamic array as a high throughput multi-detection system. In order to evaluate the system, six test samples with an increasing degree of complexity were prepared, preamplified and subsequently analysed in the Fluidigm system. Twenty-eight assays targeting different DNA elements, GM events and species-specific reference genes were used in the experiment. The large majority of the assays tested presented expected results. The power of low level detection was assessed and elements present at concentrations as low as 0.06 % were successfully detected. The approach proposed in this work presents the Fluidigm system as a suitable and promising platform for GMO multi-detection. 相似文献
44.
45.
Voorhuijzen MM van Dijk JP Prins TW Van Hoef AM Seyfarth R Kok EJ 《Analytical and bioanalytical chemistry》2012,402(2):693-701
The authenticity of food is of increasing importance for producers, retailers and consumers. All groups benefit from the correct
labelling of the contents of food products. Producers and retailers want to guarantee the origin of their products and check
for adulteration with cheaper or inferior ingredients. Consumers are also more demanding about the origin of their food for
various socioeconomic reasons. In contrast to this increasing demand, correct labelling has become much more complex because
of global transportation networks of raw materials and processed food products. Within the European integrated research project
‘Tracing the origin of food’ (TRACE), a DNA-based multiplex detection tool was developed—the padlock probe ligation and microarray
detection (PPLMD) tool. In this paper, this method is extended to a 15-plex traceability tool with a focus on products of
commercial importance such as the emmer wheat Farro della Garfagnana (FdG) and Basmati rice. The specificity of 14 plant-related
padlock probes was determined and initially validated in mixtures comprising seven or nine plant species/varieties. One nucleotide
difference in target sequence was sufficient for the distinction between the presence or absence of a specific target. At
least 5% FdG or Basmati rice was detected in mixtures with cheaper bread wheat or non-fragrant rice, respectively. The results
suggested that even lower levels of (un-)intentional adulteration could be detected. PPLMD has been shown to be a useful tool
for the detection of fraudulent/intentional admixtures in premium foods and is ready for the monitoring of correct labelling
of premium foods worldwide. 相似文献
46.
A headspace sampling method is described for concentrating milk volatiles onto a multi-channel open tubular silicone rubber trap (MCT) for thermal desorption into a GC-FID. Sections of the chromatographic profile, single peaks or combinations of compounds are recaptured with secondary MCTs during a subsequent run. The recaptured aroma is released in a controlled manner by heating the MCT in a portable heating device. An aroma release window of several minutes allows up to six people the opportunity to sniff each aroma fraction more than once. Olfactory results suggest that a synergistic combination of 2-heptanone and 2-nonanone could be responsible for a pungent cheese, sour milk-like aroma. MCTs containing single components or fractions can be desorbed into a GC-MS for compound identification. 相似文献
47.
48.
Marleen L. B. F. Hereygers Herman O. Desseyn Albert T. H. Lenstra Evy Manessi-Zoupa Spyros P. Perlepes 《Transition Metal Chemistry》1996,21(3):273-282
Summary Synthetic procedures are described that allow access to the new monomeric complexes [M(HA)2(H2O)2]·2H2O (M = Mn or Co), [M(HA)2(H2O)2] (M = Fe, Ni or Zn) and [Cu(HA)2], and to the polymeric compounds [MA(H2O)]
n
(M = Mn, Co, Ni or Zn) and [CuA]
n
, where H2A = N-methyl-2-thiooxamic acid. The X-ray crystal structure of [Mn(HA)2(H2O)2]·2H2O reveals a trans, cis, cis octahedral geometry around the metal ion. The singlydeprotonated ligand behaves as a bidentate chelate with ligated atoms being the neutral thioamide sulfur and one of the carboxylate oxygens. The complexes were characterized by elemental analyses, conductivity measurements, X-ray powder patterns, magnetic susceptibilities and spectroscopic (e.s.r., ligand field, i.r., far-i.r., Raman) studies. The vibrational analysis of the complexes is presented using OH/OD, NH/ND, CH3/CD3 and metal isotopic substitutions. All data are discussed in terms of the nature of bonding in conjunction with known or assigned structures. The dianion A2– acts as a bis-bidentate O,N/O,S bridging ligand yielding highly symmetrical squares planar (CuII) and octahedral (MnII, CoII, NiII and ZnII) polymeric compounds.Dedicated to the memory of Professor Andreas G. Galinos 相似文献
49.
Wood M Laloup M Samyn N Morris MR de Bruijn EA Maes RA Young MS Maes V De Boeck G 《Journal of chromatography. A》2004,1056(1-2):83-90
We have developed a rapid method that enables the simultaneous analysis of gamma-hydroxybutyrate (GHB) and its precursors, i.e. gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) in urine. The method comprised a simple dilution of the urine sample, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Chromatographic separation was achieved using an Atlantis dC18 column, eluted with a mixture of formic acid and methanol. The method was linear from 1-80 mg/L for GHB and 1,4-BD and from 1-50 mg/L for GBL. The limit of quantification was 1 mg/L for all analytes. The procedure, which has a total analysis time (including sample preparation) of less than 12 min, was fully validated and applied to the analysis of 182 authentic urine samples; the results were correlated with a previously published GC-MS procedure and revealed a low prevalence of GHB-positive samples. Since no commercial immunoassay is available for the routine screening of GHB, this simple and rapid method should prove useful to meet the current increased demand for the measurement of GHB and its precursors. 相似文献
50.
Manger RL Leja LS Lee SY Hungerford JM Kirkpatrick MA Yasumoto T Wekell MM 《Journal of AOAC International》2003,86(3):540-543
Although cytotoxicity assays provide several advantages over mouse bioassays, sodium channel-blocking marine toxins, such as those associated with paralytic shellfish poison (PSP), require prolonged incubation periods of 24-48 h. This is in marked contrast to in vitro detection of sodium channel-enhancing marine toxins such as ciguatoxins or brevetoxins which can be accomplished in as few as 4-6 h. We developed a modified PSP cell bioassay that is as rapid as in vitro methods for sodium channel-enhancing toxins. The cell bioassay is based on a saxitoxin-dependent antagonism of the rapid in vitro effects of brevetoxin or ciguatoxin. Comparative analysis of naturally incurred PSP residues by both antagonism cell bioassay and the mouse bioassay demonstrated significant correlation. The simplicity, sensitivity, and enhanced kinetics of the new antagonism cell bioassay format provide the basis for development of a practical alternative to conventional mouse testing for PSP. 相似文献