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排序方式: 共有133条查询结果,搜索用时 31 毫秒
61.
2,3,4-三羟基苯乙酮缩-2-羧基苯胺与铜的高灵敏度荧光反应及其应用 总被引:3,自引:0,他引:3
合成了新荧光试剂 2 ,3,4 三羟基苯乙酮缩 2 羧基苯胺 (TAFA)。详细研究了试剂与铜的荧光反应新体系的最佳适宜条件。在 pH 9.0的乙醇 /水 (3.5∶6 .5 ,V/V)溶液中 ,该试剂与铜离子形成稳定的络合物 ,组成比为 1∶1(金属∶试剂 ) ,λex/em=4 2 2 .4 / 5 6 1.6nm。所建立的铜的荧光分析方法的线性范围为 0 .5~ 12 0 .0μg/L ;检出限为 0 .2 6 μg/L。方法成功地应用于矿泉水和水中痕量铜的测定。 相似文献
62.
63.
SAAQ-CTMAB荧光光度法测定微量铝的研究 总被引:3,自引:0,他引:3
某些席夫碱具有一定的刚性平面及富电子的共轭体系 ,从而使其显示出良好的荧光特性 ,导致该类试剂在荧光分析中显出越来越重要的作用[1 ] 。虽然荧光法测定铝已有文献[2~4] 报道 ,但本文所提出的SAAQ在CTMAB存在下与铝产生荧光增敏测定微量铝的方法尚未见报道。研究表明在pH =4.0~ 5.5的乙酸铵缓冲溶液及CTMAB存在下 ,铝与SAAQ形成 1∶2的络合物。该络合物在λeχ/λem=378nm/490nm处荧光最强 ,线性范围为 0~ 2 0 0 μg·dm- 3,方法用于人发及茶叶中铝含量的测定 ,结果满意。1 试验部分1 .1 仪器与试剂… 相似文献
64.
基于非离子表面活性剂TritonX-100,以浊点萃取结合荧光光度法测定水中的苯酚,考察影响浊点萃取的各种因素。最佳实验条件为:pH=3.0的磷酸氢二钠-磷酸二氢钾缓冲溶液中,5%的TritonX-100用量2.0mL、平衡温度82℃、平衡时间8min。在此条件下,苯酚被萃取到TritonX-100表面活性剂相与水相分开。 相似文献
65.
66.
Jorge Hernández García Zoraida Sosa Ferrera Angel J. Bermejo Martín-Lázaro José J. Santana Rodríguez 《Mikrochimica acta》1995,118(3-4):185-196
Fluorescence characteristics of several polychlorinated dibenzofurans (PCDFs) of toxicological and environmental interest in the presence of cationic, anionic, neutral surfactants, -cyclodextrin and -cyclodextrin were examined. The fluorescence enhancement of 2,3,7,8-tetrachlorodibenzofuran (TTCDF) in the presence of polyoxyethylene(10) lauryl ether (C12E10) medium was utilized to establish a sensitive spectrofluorimetric method for determination of TTCDF. The optimization of variables as the concentration of surfactant, percentage of organic solvent and temperature, and effect of possible interferences from other PCDFs, polychlorinated dibenzo-p-dioxins (PCCDs), polychlorinated biphenyls (PCBs) and Arochlors were investigated. The method, which has a detection limit of 1.30 ng ml–1, has been applied to the determination of TTCDF in sea water with acceptable recoveries. 相似文献
67.
Cerium can be determined spectrofluorimetrically (em 350 nm, ex 260 nm) based on the relatively intense native fluorescence of the cerium(III) aquo-ion. The main potential interference in the analysis of steel from iron(III), cerium(IV) and chromium(VI) are removed by use of a carrier solution containing 2.5% w/v hydroxylammonium chloride. The slight residual interference from iron(II) can be corrected by a matrix matching factor linearly related to the amount of iron present. The calibration graphs are linear over the range 0–7 g ml–1 based on 250 l injection volumes. The sampling rate was 30 h–1. The relative standard deviation was 2.0% (n=5) at 3 g ml–1 cerium. The system has been applied to the determination of cerium in carbon or low alloy steels. 相似文献
68.
Silvia?Ortega-Algar Natividad?Ramos-Martos Antonio?Molina-DíazEmail author 《Mikrochimica acta》2004,147(4):211-217
We describe a single continuous-flow method for the determination of Quinine (QN) and Quinidine (QD) based on the enhancement of their native fluorescence by on-line transitory retention on a solid support placed in a flow cell. KCl solution was used as carrier/self-eluting solution. The active solid surface is regenerated by the carrier itself which also acts as eluting solution, thus making the microsensing zone reusable for subsequent measurements.In the range of 40 to 1260µL, the response of the sensor (exc/em=250/450nm) was directly proportional to the sample volume injected. The sensor was calibrated for three injection volumes: 40, 600 and 1000µL, responding linearly in the range of 40–800, 2–40 and 0.4–20µgL–1 of QN and 20–600, 5–40 and 0.9–20µgL–1 of QD with detection limits of 2.2, 0.2 and 0.1µgL–1 (QN) and 3.9, 0.4 and 0.2µgL–1 (QD), respectively. The relative standard deviation for ten independent determinations is 1.0% (QN) and 3.9% (QD). The sampling frequency ranges between 40 and 22h–1 depending on the sample volume injected. This sensor was satisfactorily applied to the determination of QN in soft drink samples and a shampoo, and to the determination of QD in pharmaceutical preparations with equally satisfactory results. 相似文献
69.
A. Espinosa-Mansilla A. Muñoz de la Peña D. González Gómez F. Salinas 《Analytica chimica acta》2005,531(2):257-266
Multivariate methods comprise of a group of chemometric tools allowing the analysis of different analytical data, i.e., spectroscopic, chromatographic obtained from multichannel detector systems. Second-way data are widely used in analytical applications in combination with multivariate calibration methods, but three- and higher-way data are yet not as widely applied. In complex biological samples, the employment of the three-way data is of special interest, as they may be combined with methods that exploit the second-order advantage allowing calculating individual concentrations of the analytes of interest in the presence of unknown interferences in untreated samples. A very sensitive and selective method is proposed, by coupling photoinduced fluorescence and multivariate analysis of the three-way data excitation-emission fluorescence matrices (EEMs), of the photoproducts obtained from UV irradiation of three fluoroquinolones: enoxacin (ENO), norfloxacin (NOR) and ofloxacin (OFLO). The application of a previous photoirrradiation process allows the determination of mixtures of ENO, NOR and OFLO, in urine samples at biological levels without sample pretreatments. The resolution ability of N-way partial least squares (N-PLS), parallel factor analysis (PARAFAC) and self weighted alternating trilinear decomposition (SWATLD), is compared with partial least squares (PLS) and unfolded-PLS (U-PLS), in the analysis of ENO, NOR and OFLO in human urine samples. 相似文献
70.
A method for the determination of trace amounts of 1-naphthylacetic acid (NAA) has been developed, based on solid-phase spectrofluorimetry. The relative fluorescence intensity of NAA fixed on Sephadex QAE A-25 gel was measured directly after packing the gel beads in a 1-mm silica cell, using a solid-phase attachment. The wavelengths of excitation and emission were 280 and 336 nm, respectively. The applicable concentration range was from 0.3 to 18 ng/ ml, with a relative standard deviation of 1.4% (for a level of 9 ng/ml) and a detection limit of 0.09 ng/ml. The method was applied to the determination of NAA in commercial formulations and natural waters. The method is more sensitive and selective than other methods described in the literature. 相似文献