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41.
Marcelo Coelho Silva Jeancarlo Pereira dos Anjos Lilian Lefol Nani Guarieiro Bruna A. Souza Machado 《Molecules (Basel, Switzerland)》2021,26(16)
There are a significant number of analytical methodologies employing different techniques to determine phenolic compounds in beverages. However, these methods employ long sample preparation processes and great time consumption. The aim of this paper was the development of a simple method for evaluating the phenolic compounds’ presence in Brazilian craft beers without a previous extraction step. Catechin, caffeic acid, epicatechin, p-coumaric acid, hydrated rutin, trans-ferulic acid, quercetin, kaempferol, and formononetin were analyzed in fifteen different craft beers. The method showed good linearity (R2 ≥ 0.9966). The limit of detection ranged from 0.08 to 0.83 mg L−1, and limits of quantification were between 0.27 and 2.78 mg L−1. The method showed a satisfactory precision (RSD ≤ 16.2%). A good accuracy was obtained by the proposed method for all phenolic compounds in craft beer (68.6% ˂ accuracy ˂ 112%). Catechin showed higher concentrations (up to 124.8 mg L−1) in the samples, followed by epicatechin (up to 51.1 mg L−1) and caffeic acid (up to 8.13 mg L−1). Rutin and formononetin were observed in all analyzed samples (0.52 mg L−1 to 2.40 mg L−1), and kaempferol was less present in the samples. The presence of plant origin products was determinant for the occurrence of the highest concentrations of phenolic compounds in Brazilian craft beers. 相似文献
42.
高效液相色谱法测定饮料中的食用色素 总被引:4,自引:0,他引:4
利用吸附-解吸过程提取饮料中的食用色素,采用YWG—C1810μm不锈钢柱,以甲醇-0.02mol/L乙酸铵溶液作流动相,紫外检测波长为254nm,利用梯度洗脱程序分离食用色素,采用高效液相色谱法测定。样品溶液的最佳pH值为6。柠檬黄、苋菜红、胭脂红、日落黄、亮蓝的检出限分剐为0.14、0.20、0.29、0.25、1.04μg/mL。回收率为90.0%~96.7%,测定结果的相对标准偏差为1.37%-2.98%。 相似文献
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A sensitive and fast analytical method using purge-and-trap on-line coupling with gas chromatography was developed for the determination of trace volatile sulfur compounds including dimethyl sulfide (DMS), ethyl-methyl sulfide (EMS), and dimethyl disulfide (DMDS) in beverage and coffee samples. The analytes were purged for 12min from the sample by high purity nitrogen at a flow rate of 35KPa and preconcentrated in the cooled fused-silica capillary trap at –75°C. The NaCl content in the samples was maintained at 10%. The volatile sulfur compounds were separated with an Agilent-6890 gas chromatograph by a suitable temperature program and detected by means of a flame photometric detector (FPD). The detection limits were 80ngL–1 for DMS, 80ngL–1 for EMS, and 100ngL–1 for DMDS, respectively. This method was successfully applied to the determination of volatile sulfur compounds in different beverage and coffee samples. 相似文献
45.
Harada Layse H. P. da Costa Aline C. Filho Rubens Maciel 《Applied biochemistry and biotechnology》2002,98(1-9):1009-1023
The objective of this work was to develop a model for an extractive ethanol fermentation in a simple and rapid way. This model
must be sufficiently reliable to be used for posterior optimization and control studies. A hybrid neural model was developed,
combining mass and energy balances with neural networks, which describe the process kinetics. To determine the best model,
two structures of neural networks were compared: the functional link networks and the feedforward neural networks. The two
structures are shown to describe well the process kinetics, and the advantages of using the functional link networks are discussed. 相似文献
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An amperometric biosensor system which uses screen-printed electrodes to simultaneously detect d-glucose and l-lactate has been developed and applied for simple and rapid determination of d-glucose and l-lactate levels in lactic fermenting beverages. The system was constructed from three-dimensionally layered electrodes. Taking into consideration the effects of easily oxidized substances contained in the samples, ferricyanide ions, which are electrochemically oxidized at a lower voltage, were chosen as a mediator. A linear relationship between steady-state current and concentration was found over a range of 1-100 mM (d-glucose) and 1-50 mM (l-lactate); the variation coefficients were 1.43% (n = 10) and 3.50% (n = 10) for the d-glucose and l-lactate sensors, respectively. When applied to lactic fermenting beverages, there was good agreement between the results obtained by the proposed sensing system and those obtained by the HPLC method. Using the proposed method, assays were completed within 5 min. 相似文献
49.
建立一种微波消解–石墨炉原子吸收光谱法测定露酒中铅的方法。样品蒸干后经微波消解前处理,然后用石墨炉原子吸收光谱法测定露酒中的铅的浓度,铅的浓度在0.0~20.0 ng/mL范围内呈良好的线性关系,线性相关系数为0.9996,取样2.00 mL定容至25.0 mL,得方法的检出限为0.003 mg/L,方法的定量限为0.010 mg/L。测定结果的相对标准偏差为3.4%~5.5%,加标回收率为88%~104%。该法具有灵敏度高,准确度、精密度良好,检测过程快速、省力等优点,适合日常批量检测。 相似文献
50.
自动化联用分析技术对于降低人力强度、提高效率和保证数据重现性等具有重要意义。硼亲和固相微萃取(BA-SPME)是近十年出现的用于富集顺式二羟基化合物的独特工具,但BA-SPME与高效液相色谱(HPLC)的自动化在线联用还未见报道。该文报道了一种新颖的管内BA-SPME-HPLC全自动在线联用方法,用于分析茶饮料中的顺式二羟基化合物。该自动化在线联用方法利用自动进样器通过六通阀的切换实现流路连接。制备了管内BA-SPME毛细管,考察了涂层柱的柱容量,并对其形貌进行了表征,考察并优化了影响实际样品分离效果的因素。最后,利用该联用方法对3种不同品牌的茶饮料进行了分析,并对沏茶温度对茶水中顺式二羟基化合物含量的影响进行了评价。 相似文献