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2,4‐Dichlorophenoxy acetic acid herbicide is spectrophotometrically determined by diazotization method in a flow injection assembly. The method is based on base hydrolysis of herbicides. The hydrolyzed product 2,4‐dichlorophenol is reacted with diazotized sulfanilic acid. The absorbance of the resulting coloured product was measured at 480 nm. The calibration graph is linear over the range of 0.2–20 μgmL?1, with a relative standard deviation of (RSD) of 7.2% and sample throughput of 90 samples h?1. The % recovery for determination of 2,4‐dichlorophenoxy acetic acid was found to be 92.0–95.3%. The method is easy, simple and faster than the established chromatographic method. The method was applied for determination of 2,4‐dichlorophenoxy acetic acid herbicide in commercial formulations and for residue determination in fruits and food samples. 相似文献
54.
气相色谱-质谱法同时测定大豆中14种苯氧羧酸类除草剂 总被引:6,自引:0,他引:6
建立了气相色谱(GC)-质谱(MS)选择离子监测(SIM)法测定大豆中14种苯氧羧酸类除草剂多残留量检测方法。本研究对样品前处理进行了优化,样品经乙腈-酸化水(含10%浓硫酸)提取,凝胶渗透色谱(GPC)和阴离子交换柱净化和富集,三甲硅基重氮甲烷(TMS)甲酯化,采用GC-MS测定并确证,最后用外标法定量。3个样品添加水平分别为0.02、0.04和0.1 mg/kg,回收率在78.8%~94.3%之间,RSD<20%。线性、回收率和检出限均符合残留分析要求。 相似文献
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高效液相色谱法和液相色谱-质谱法测定大豆中的磺酰脲类除草剂多残留量 总被引:7,自引:1,他引:7
建立了高效液相色谱(HPLC)法和液相色谱-质谱(LC-MS)选择离子监测法同时检测大豆中10种磺酰脲类除草剂多残留量的方法。样品经乙腈提取、正己烷液-液分配、弗罗里硅土填充柱净化,然后采用RP-HPLC-DAD和HPLC-MS方法测定。对HPLC和LC-MS法的分离条件、样品前处理条件进行了优化。建立的方法简便、快速、灵敏,净化效果较好,线性、回收率、精密度和检出限均符合残留分析的要求,可同时满足进出口大豆中多种除草剂残留量同时检验的需要。 相似文献
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Wang JG Li ZM Ma N Wang BL Jiang L Pang SS Lee YT Guddat LW Duggleby RG 《Journal of computer-aided molecular design》2005,19(11):801-820
Summary Acetohydroxyacid synthase (AHAS; EC 2.2.1.6) catalyzes the first common step in branched-chain amino acid biosynthesis. The
enzyme is inhibited by several chemical classes of compounds and this inhibition is the basis of action of the sulfonylurea
and imidazolinone herbicides. The commercial sulfonylureas contain a pyrimidine or a triazine ring that is substituted at
both meta positions, thus obeying the initial rules proposed by Levitt. Here we assess the activity of 69 monosubstituted sulfonylurea
analogs and related compounds as inhibitors of pure recombinant Arabidopsis thaliana AHAS and show that disubstitution is not absolutely essential as exemplified by our novel herbicide, monosulfuron (2-nitro-N-(4′-methyl-pyrimidin−2′-yl) phenyl-sulfonylurea), which has a pyrimidine ring with a single meta substituent. A subset of these compounds was tested for herbicidal activity and it was shown that their effect in vivo correlates well with their potency in vitro as AHAS inhibitors. Three-dimensional quantitative structure–activity relationships were developed using comparative molecular
field analysis and comparative molecular similarity indices analysis. For the latter, the best result was obtained when steric,
electrostatic, hydrophobic and H-bond acceptor factors were taken into consideration. The resulting fields were mapped on
to the published crystal structure of the yeast enzyme and it was shown that the steric and hydrophobic fields are in good
agreement with sulfonylurea-AHAS interaction geometry. 相似文献
58.
采用成核/晶化隔离法将草甘膦(Glyphosate:gly)插层组装到镁铝水滑石层间,制得草甘膦插层镁铝水滑石(MgAl-LDH-gly).在水和碳酸钠溶液中考察了gly的释放性能,初步探讨了MgAl-LDH-gly在这两种溶液中的释放机理,认为其释放机理主要为离子交换,释放速率较大的初期符合一级动力学过程.用磷酸缓冲溶液考察环境pH值对MgAl-LDH-gly释放的影响,证明弱碱性(pH=7.6)和偏中性(pH=6.6)环境有利于其释放;探讨混合无机阴离子溶液中无机阴离子对MgAl-LDH-gly释放性能的影响,结果表明,MgAl-LDH-gly的释放速率及释出量在所考察范围内由溶液中无机阴离子的总浓度决定. 相似文献
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Hülya Mercan 《International journal of environmental analytical chemistry》2013,93(12):879-890
A differential pulse polarographic method for the determination of the herbicide thiazopyr has been developed. The polarographic study of thiazopyr exhibited two well-defined cathodic peaks within the pH range of 1.0 to 8.0. The variation of pH and polarographic parameters indicated that the optimum conditions under which thiazopyr could be reduced were a pH 7.0 BR buffer solution, a reduction peak potential of ?1270 mV (vs. SCE), scan rate of 5 mV s?1, pulse amplitude of 50 mV with pulse duration of 50 ms at an ambient temperature of 25 ± 3°C. The main reduction peak was characterised by cyclic voltammetry as being irreversible and diffusion-controlled. A linear relationship between the peak current and the concentration of thiazopyr was obtained in the range of 0.43–38.6 µg mL?1, with a detection limit of 0.127 µg mL?1. The proposed method was successfully applied to the determination of thiazopyr in spiked fruit juice and soil samples. The mean recoveries of the 19.8 µg g?1 and 3.96 µg mL?1 thiazopyr spiked to soil and orange juice were 20.2 ± 1.0 µg g?1 and 3.84 ± 0.12 µg mL?1, at 95% confidence level, respectively. The sufficiently good recoveries and low relative standard deviation (RSD) data confirm the high accuracy and precision of the proposed method. The interferences effects of several commonly used pesticides and inorganic species were also studied. Interfering effects were eliminated either by providing selectivity with pH, or using EDTA as complexing agent. 相似文献