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11.
A rapid flow-injection method with chemiluminescence (CL) detection is described for the determination of glutathione (GSH).
The method is based on the CL reaction of luminol and hydrogen peroxide. GSH can greatly enhance the chemiluminescence intensity
in 0.1 mol/L borax–sodium hydroxide buffer solution (pH = 9.7). The maximum CL intensity was directly proportional to the
concentration of GSH in the range 3.0 × 10−7–2.0 × 10−5 mol/L, and the detection limit was 6.8 × 10−8 mol/L. The relative standard deviation was 3.4% for 5.0 × 10−6 mol/L of GSH (n = 11).
Received October 23, 2001; accepted June 18, 2002 相似文献
12.
流动注射-化学发光法定量测定同一水域中的腐殖酸 总被引:2,自引:0,他引:2
采用流动注射-化学发光(FI-CL)这一灵敏的检测方法,通过条件实验与参数优化,优选了测定环境中痕量多羟基酚类化合物的发光体系,通过考察天然水体中的腐殖酸对化学发光-多羟基酚测定体系的影响,为来自于水及土壤中的实际样品中腐殖酸的检测提供了参考,建立了同一区域水体中腐殖酸的化学发光定量测定方法。 所得线性回归方程y=70.36x+540.1,相关系数r=0.995 4,线性范围为3~15 mg·L-1,检测限为0.749 mg·L-1,HA浓度为6 mg·L-1时的相对标准偏差(RSD)为1.08%。 相似文献
13.
Determination of organophosphate and carbamate pesticides based on enzyme inhibition using a pH-sensitive fluorescence probe 总被引:1,自引:0,他引:1
A flow injection system for the determination of organophosphate and carbamate pesticides is described. A sensitive fluorescence probe was synthesized and used as the pH indicator to detect the inhibition of the enzyme acetylcholinesterase (AChE). The percentage inhibition of enzyme activity is correlated to the pesticide concentration. Several parameters influencing the performance of the system are discussed. The detection limits of 3.5, 50, 12 and 25 μg/l for carbofuran, carbaryl, paraoxon and dichlorvos, in pure water, respectively were achieved with an incubation time of 10 min. A complete cycle of analysis, including incubation time, took 14 min. The detection system has been applied to the determination of carbofuran in spiked vegetable juices (Chinese cabbage and cole), achieving recovery values between 93.2 and 107% for Chinese cabbage juice and 108 and 118% for cole juice at the different concentration levels assayed. 相似文献
14.
A sensitive and fast method for the determination of nitrous acid (HONO) in air is described. The method combines a continuous collection of nitrous acid into a thin film of absorption liquid in a cylindrical wet effluent diffusion denuder (CWEDD) and on-line analysis of collected nitrous acid at the denuder concentrate employing a flow-injection analysis (FIA) where nitrous acid is oxidized into peroxynitrous acid and a chemiluminescent light emitted during the reaction of peroxynitrite with luminol is detected. Various absorption solutions (carbonate, bicarbonate, phosphate) as well as deionized water were compared from point of view of collection efficiency of nitrous acid at the CWEDD and selectivity and sensitivity of nitrous acid determination in air.All tested liquids provide quantitative collection of HONO in the CWEDD at the air flow rate of 1 L min−1. The detection limit of nitrous acid of 15 ppt (v/v) is the same for all tested liquids. Small positive interference of nitrogen dioxide and peroxyacetylnitrate has been found. The lowest interference of NO2 was found for 1 × 10−4 M NaHCO3 (pH 6.4; 0.18%) while for deionized water interference of NO2 (0.28%) was slightly higher. The lowest interference of peroxyacetylnitrate was found for deionized water (1.46%). No enhanced formation of HONO inside the cylindrical wet effluent diffusion denuder was observed for simultaneous bringing of nitrogen dioxide together with phenol, p-cresol, guaiacol, catechol, o-nitrophenol as well as with n-octane, n-nonane, n-decane, isoprene, α-pinene, β-pinene, camphene, 3-carene, α-phellandrene, S-limonene, benzene, toluene or o-xylene in comparison with formation of HONO only in the presence NO2.Deionized water was chosen as the optimum absorption liquid for the sampling of atmospheric nitrous acid at the CWEDD as well as for FIA chemiluminescent detection. The time resolution is 70 s and the response time is 164 s. The calibration curve is linear over 4 orders of magnitude (0.045-450 ppb HONO). The CWEDD-FIA technique has been applied to the measurement of nitrous acid in urban air. 相似文献
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The monitoring of insulin is of great relevance for the management of diabetes, the detection of pancreatic islet-cell malfunction, the definition of hypoglycemia, and the diagnosis of insulinoma. A liposomal immunosensing system for the determination of insulin was developed in this study. The insulin sensor was constructed by the immobilization of anti-insulin antibodies on the inner wall of the microcapillary immunoseparator. Liposomes tagged with anti-insulin and encapsulating a fluorescent dye were used as the detectable label. In the presence of insulin, sandwich immunocomplexes were formed between the immobilized antibodies in the column, the sample of insulin, and the antibody-tagged sulforhodamine B-dye-loaded liposomes. Signals generated by lysing the bound liposomes with 30 mM n-octyl-β-d-glucopyranoside were measured by a fluorescence detector. The detected signal was directly proportional to the amount of insulin in the test sample. The liposomal immunosensing system successfully detected as low as 136 attomole. MeOH (30%) was used for the regeneration of antibody-binding sites in the microcapillary after each measurement, which allowed the immunoseparator to be used for at least 70 repeated assays. The antibody activity in this proposed microcapillary immunoseparator could be well maintained for at least 1 week. The calibration curve for insulin in Tris-buffered saline had a linear dynamic range of 10 pM-10 nM, and the total assay time was less than 30 min. The coefficient of variation for triplicate measurements was <5.00%, which indicated that well-reproducible results can be obtained by this newly developed method. 相似文献
17.
This paper reports on a microfluidic device for the flow-injection/electrochemistry analysis of nitroaromatic explosive. The response is very fast (150 assays/h), highly sensitive (detection limit 7.0 μg L−1), reproducible and stable (R.S.D. = 2.0%; n = 30) and linear (over 20-100 μg L−1 range). Relevant experimental parameters have been optimized. The new microsystem offers great promise for on-site monitoring of TNT, with significant advantages of speed/warning, sample size, efficiency and cost. Most favorable S/N characteristics were obtained at the Hg/Au-amalgam end-channel detector. 相似文献
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流动注射氢化物石墨炉原子吸收法的应用研究 Ⅰ.——实验装置与分析性能 总被引:2,自引:0,他引:2
氢化物石墨炉联用技术的原理是先在较低温度下将氢化物蒸气通入石墨炉并分解沉积于石墨管的内表面,然后再在高温下原子化。该法能明显提高灵敏度,消除液相和气相干扰。本文采用自制的半自动氢化物石墨炉进样系统及流动注射氢化物发生器,直接在普通石墨炉上进行氢化物石墨炉分析,研究了部分元素的测定条件,建立的方法操作方便,灵敏度高,耗样少,线性范围宽,是一种值得推广的新方法。 相似文献