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21.
Xinnan Wang Shuping Xu Haibo Li Jinlong Tao Bing Zhao Weiqing Xu 《Journal of Raman spectroscopy : JRS》2012,43(3):459-463
A three‐dimensional surface‐enhanced Raman scattering (SERS) substrate via the self‐assembly of properly sized Au nanoparticles in anodic aluminum oxide templates was designed and prepared. Au nanoparticles first underwent hydrophobic surface modification. Then, the hydrophobic Au nanoparticles self‐assembled, aggregated and formed many hot spots in the anodic aluminum oxide templates through a supramolecular interaction. We chose thiophenol as a probe molecule to evaluate the SERS enhancement ability of this three‐dimensional substrate. The enhancement factor was calculated to be 4.6 × 106 under the radiation of a 785‐nm laser. By further comparing SERS signals from different points on the same substrate, we confirmed that this substrate possessed good reproducibility and could be applied for SERS detection. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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An original HPLC method coupled to spectrofluorimetric detection is presented for the simultaneous analysis in dried blood spots (DBS) of cocaine and two important metabolites, namely benzoylecgonine (its main metabolite) and cocaethylene (the active metabolite formed in the presence of ethanol). The chromatographic analysis was carried out on a C8 column, using a mobile phase containing phosphate buffer (pH 3.0)-acetonitrile (85:15, v/v). Native analyte fluorescence was monitored at 315 nm while exciting at 230 nm. A fast and feasible sample pre-treatment was implemented by solvent extraction, obtaining good extraction yields (>91%) and satisfactory precision values (RSD<4.8%). The method was successfully applied to DBS samples collected from some cocaine users, both with and without concomitant ethanol intake. The results were in good agreement with those obtained from plasma samples subjected to an original solid-phase extraction procedure on C8 cartridges. The method has demonstrated to be suitable for the monitoring of cocaine/ethanol use by means of DBS or plasma testing. Assays are in progress to apply this method on the street, for the control of subjects suspected of driving under the influence of psychotropic substances. 相似文献
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Rao RN Maurya PK Ramesh M Srinivas R Agwane SB 《Biomedical chromatography : BMC》2010,24(12):1356-1364
A high‐throughput liquid chromatography–electrospray ionization mass spectrometric (LC–ESI‐MS) method for screening of sirolimus on dried blood spots (DBS) was developed and validated. It involves solvent extraction of a punch of DBS followed by reversed‐phase LC on a relatively new monolithic column consisting of a silica rod with bimodal pore structure and detection by ESI‐MS. The run time was less than 3 min with a very low backpressure at a flow rate of 0.5 mL/min. The method can analyze more than 100 samples in an 8 h working day, including sample preparation. The assay was linear from 1 to 100 ng/mL. The mean recovery was 92.42%. The mean inter‐day and intra‐day precisions were 1.23 and 1.41%, respectively. The developed method is simple, rapid and useful for clinical applications. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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人、车、路、环境和交通管理构成了道路交通系统,造成道路交通事故的原因是综合、复杂的。正确快速地分析事故成因,有助于提升交通管理水平,减少交通事故的发生。近年来,关联规则模型及其扩展在事故多发点成因分析中备受关注。针对关联规则分析中传统的兴趣度度量方法和Apriori算法的局限,考虑小概率因子对交通事故的影响,提出了改进的交通事故多发点成因分析方法,明确评价因素和结果之间的关联程度,提高挖掘效率。基于浙江省某市交通事故数据,结合人、车、环境与时空因素对方法进行了验证,并对方法的分析效率和结果的有效性进行了讨论。 相似文献
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In this paper,we define a class of domains in R n .Using the synchronous coupling of reflecting Brownian motion,we obtain the monotonicity property of the solution of the heat equation with the Neumann boundary conditions.We then show that the hot spots conjecture holds for this class of domains. 相似文献
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Qin Li Di Cao Yue Huang Hong Xu Chen Yu Zhiping Li 《Biomedical chromatography : BMC》2013,27(3):327-334
A bioanalytical method for the quantification of tacrolimus (TAC) on dried blood spots (DBS) using liquid chromatography, electrospray ionization coupled with tandem mass spectrometry (LC‐ESI‐MS/MS) was developed and validated. It involves solvent extraction of a punch disk of DBS followed by liquid–liquid extraction. The analyte and the internal standard (IS, ascomycin) were separated on a phenyl column using an isocratic mobile phase elution at a flow rate of 0.3 mL/min. The assay was linear from 1 to 80 ng/mL. The mean recovery of TAC was 76.6%. Intra‐assay, inter‐assay imprecision and biases were all less than 15%. TAC on DBS was stable for at least 10 days at room temperature, and at least 24 h at 50°C. A chromatographic effect of the filter paper (Whatman 903) was not detected. The volume of blood (15–50 μL) and hematocrit of blood (ranging from 23.2 to 48.6%) did not show a significant influence on detection of TAC concentration by DBS‐LC‐MS/MS. Fifty samples from patients were detected by both DBS‐LC‐MS/MS and microparticle enzyme‐linked immunoassay (MEIA). TAC concentrations measured by DBS‐LC‐MS/MS method tended to be lower than those by MEIA. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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A higher correlation tends to yield a more accurate prediction,so that a correlation as high as possible has been searched for and employed in the prediction of solar activity.Instead of using geomagnetic activity during the descending phase of the solar cycle,the minimum annual aa index (aa min) is used as an indicator for the ensuing maximum amplitude (R m) of the sunspot cycle.A four-cycle periodicity is roughly shown in the correlation between R m and aa min.The widely accepted Ohl's precursor predictio... 相似文献
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Tanja Vnučec Popov Lea Cvitkovič Maričič Helena Prosen Darinka Brodnjak Vončina 《Biomedical chromatography : BMC》2013,27(8):1054-1061
An LC‐MS/MS method for determination of the anti‐epileptic drug topiramate (TPM) in dried blood spot (DBS) samples was developed and validated. DBS samples were prepared by spotting 30 μL of spiked whole blood onto FTATM DMPK‐C cards and drying for at least 3 h. Six‐millimetre punched spots were then extracted by using a mixture of methanol and water (90:10, v/v) with deuterated internal standard (topiramate‐d12). The extracted samples were injected into a liquid chromatograph equipped with a tandem mass spectrometric detector. Negative ions were monitored in the selected reaction monitoring mode and transitions m/z 338.2 → 78.1 and m/z 350.3 → 78.1 were used for the quantitative evaluation of TPM and internal standard, respectively. The results obtained from validation were statistically evaluated according to the requirements of the European Medicines Agency and US Food and Drug Administration regulatory guidelines. The linearity of the method was checked within a concentration range from 10 to 2000 ng/mL. The validation results indicate that the method is accurate, precise, sensitive, selective and reproducible. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献