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121.
122.
用光电直接光谱法分析了高纯阴极铜中的分析。该方法简便、快速,分析结果准确、可靠。 相似文献
123.
苯丁锡原药杂质的GC-MS分析 总被引:1,自引:0,他引:1
以甲醇萃取苯丁锡原药中杂质,进行GC-MS分析,采用NIST谱库检索和人工解谱方法共鉴定出其中10个杂质,包括二(2-甲基-2-苯基丙基)锡等。 相似文献
124.
用电感耦合等离子体质谱法(ICP-MS)法直接测定铅栅板中钙、锡、铝、锑、银、铋、铁、锌、镍、镉、铜、砷等12种元素含量。样品用硝酸(1+2)溶解后,用硫酸作沉淀剂,95%~98%的铅以生成PbSO4的形式沉淀,降低了测量过程中的铅离子强度,得到了较低的检出限。加入适量的盐酸,有效地防止了锡、锑等元素的水解。选择适当的同位素,克服了测定过程中的质谱干扰,以元素^45Sc、^115In、^204Tl作内标,采用内标法有效地补偿了因基体效应、接口效应及仪器波动的影响。方法的加标回收率为93.2%~105.0%,相对标准偏差为2.0%~7.0%。 相似文献
125.
A. M. Samoylov M. K. Sharov S. A. Buchnev A. M. Khoviv E. A. Dolgopolova 《Journal of Crystal Growth》2002,240(3-4):340-346
The comparison of the results of chemical composition, crystal structure, electronic properties and infrared photoconductivity investigations of PbTe/Si and PbTe/SiO2/Si heterostructures doped with Ga atoms by two different techniques is presented in this work. One of these techniques is principally based on the vapour-phase doping procedure of PbTe/Si and PbTe/SiO2/Si heterostructures, which were previously formed by the modified “hot wall” technique. The second method of PbTe(Ga)/Si and PbTe(Ga)/SiO2/Si heterostructure preparation is based upon the fabrication of lead telluride films, which have been doped with Ga atoms in the layer condensation process directly. The lattice parameter and charge carrier density evolutions with the Ga impurity concentration show principally the different character of PbTe(Ga)/Si films prepared by these techniques. It has been proposed that complicated amphoteric (donor or acceptor) behaviour of Ga atoms may be explained by different mechanisms of substitution or implantation of impurity atoms in the crystal structure of lead telluride. 相似文献
126.
The influence of the intensity of melt stirring on the radial impurity distribution and optical quality of proustite single crystals grown by the Stockbarger method using ACRT is studied by the example of Cu, Sb and Mg impurities. We report results obtained in a wide range of Taylor numbers (1.9×105<Ta<7.12×107). The studies revealed that the ACRT can be applied validly to decrease the impurity content during the growing of high-quality single crystals. 相似文献
127.
ICP-AES法测定锡铅焊料中铜铁镉锌铝铋 总被引:4,自引:0,他引:4
锡铅焊料试样经盐酸、硝酸分解后,加入一定量的硫酸沉淀分离基体铅,以盐酸一氢溴酸排锡后,采用ICP—AES法同时测定铜、铁、镉、锌、铝、铋。方法没有谱线和背景干扰,检出限铜为0.000034%,铁为0.000038%,镉为0.000026%,锌为0.000071%,铝为0.00025%,铋为0.00060%,回收率在91.09/5~99.2%之间。完全满足锡铅焊料中的铜、铁、镉、锌、铝、铋测定的要求。 相似文献
128.
The influence of Cu(II) impurity on chemical equilibria in unsaturated and saturated ammonium oxalate (AO) aqueous solutions was investigated as a function of concentration ci of impurity. Using the computer programme “Hyss” the species present in the solutions were analysed. It was found that in the aqueous solutions of ammonium oxalate containing Cu(II) ions the following species are formed: Cu2+, Cu(OH)+, Cu(OH)2, CuC2O40 and Cu(C2O4)22− in addition to C2O42−, HC2O4−, H2C2O4 and (NH4)2C2O40 species, and their concentration depends on concentrations ci of Cu(II) impurity and c of ammonium oxalate. The dependences of solution pH and of absorbance A and the corresponding wavelength λ for unsaturated aqueous solutions on ammonium oxalate concentration c containing different concentrations ci of Cu(II) ions showed three well-defined regions characterised by transition values of solution pH or solute concentration c. Speciation analysis revealed that Cu2+ and CuC2O40, CuC2O40 and Cu(C2O4)22−, and Cu(C2O4)22− complexes are predominantly present in the solute concentration intervals c≤0.01 mol/dm3, 0.01 mol/dm3 <c<0.03 mol/dm3 and c≥0.03 mol/dm3, respectively. The concentration interval range 0.01 mol/dm3 <c<0.03 mol/dm3 corresponds to the pH interval where Cu(OH)2 is precipitated. It was found that the solubility of ammonium oxalate at 30 °C increases practically linearly with an increase in the concentration of Cu(II) impurity. Speciation analysis of saturated aqueous solutions of ammonium oxalate revealed that Cu(II) ions contained in AO saturated solutions exist mainly as Cu(C2O4)22−-type complexes, and the increase in the solubility of AO in the presence of Cu(II) impurity is essentially due to an increase in the ratio of the concentrations of CuC2O40 and Cu(C2O4)22− species. 相似文献
129.
130.
Angel Arturo Gaona-Galdos Pedro López García María Segunda Aurora-Prado Maria Inês Rocha Miritello Santoro Érika Rosa Maria Kedor-Hackmann 《Talanta》2008,77(2):673-678
A reversed-phase high performance liquid chromatographic (RP-HPLC) method for determination of econazole nitrate, preservatives (methylparaben and propylparaben) and its main impurities (4-chlorobenzyl alcohol and alpha-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol) in cream formulations, has been developed and validated. Separation was achieved on a column Bondclone® C18 (300 mm × 3.9 mm i.d., 10 μm) using a gradient method with mobile phase composed of methanol and water. The flow rate was 1.4 mL min−1, temperature of the column was 25 °C and the detection was made at 220 nm. Miconazole nitrate was used as an internal standard. The total run time was less than 15 min. The analytical curves presented coefficient of correlation upper to 0.99 and detection and quantitation limits were calculated for all molecules. Excellent accuracy and precision were obtained for econazole nitrate. Recoveries varied from 97.9 to 102.3% and intra- and inter-day precisions, calculated as relative standard deviation (R.S.D.), were lower than 2.2%. Specificity, robustness and assay for econazole nitrate were also determined. The method allowed the quantitative determination of econazole nitrate, its impurities and preservatives and could be applied as a stability-indicating method for econazole nitrate in cream formulations. 相似文献