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81.
硒钼杂多酸—罗丹明B离子缔合物显色反应的研究与应用 总被引:3,自引:0,他引:3
刘淑萍 《理化检验(化学分册)》2001,37(8):353-354,359
研究了在聚乙烯醇分散剂存在下 ,硒 钼酸铵 罗丹明B(RDB)三元缔合物的显色反应。建立了测定硒碘盐中微量硒的新方法。离子缔合物的最大吸收波长为 5 70nm ,表观摩尔吸光系数ε570 =5 .6× 10 5L·mol- 1·cm- 1。在测定条件下 ,硒含量在 0~ 6μg/ 2 5ml范围内符合比耳定律。对于硒碘盐样品的测定 ,RSD≤ 2 .5 % ,结果满意 相似文献
82.
罗丹明B—I3^—离子缔合物共振散射测定环境水样中的铬(Ⅵ)和铬(Ⅲ) 总被引:4,自引:0,他引:4
研究在磷酸介质中,罗丹明B与I3^-的离子缔合物的共振散射光谱。确定了散射光强度与溶液中Cr(VI)浓度的关系。提出了共振散射测定Cr(VI)的新方法,方法的检出限为2.2ug/L,线性范围为10.0-500ug/L,结合离子交换分离法,用于环境水样中铬的形态分析,结果满意。 相似文献
83.
Rodica Zvoianu Cristina R. Dias M. Farinha Portela 《Reaction Kinetics and Catalysis Letters》2001,72(2):201-208
The acid-base properties of a series of SiO2-supported NiMoO4 catalysts were investigated by temperature-programmed desorption of NH3 and CO2. Results show that supported catalysts with ca. one monolayer of the active phase are less acidic than the unsupported stoichiometric NiMoO4. 相似文献
84.
以含磷较低的铁合金作底液,以钼酸铵为显色剂,用磷钼蓝光度法测定铁合金中的磷。磷钼蓝的摩尔吸光系数为7.8×10~5L/(mol·cm),与磷钼黄光度法、氟化钠-氯化亚锡还原磷钼蓝光度法相比,测定灵敏度有不同程度的提高。该方法用于实际样品分析,结果准确、可靠。 相似文献
85.
Xue-Mei Li Rui-Rui Zhao Yan Yang Xue Wei Lv Yu-Ling Wei Rui Tan Jun-Feng Zhang Ying Zhou 《中国化学快报》2017,28(6):1258-1261
A rhodamine-based sensor (1) has been developed for the detection of chromium ions. Cr3+-induced opening of the rhodamine spirocycle in sensor (1) led to the distinct colorimetric and fluorescence responses. Among all the tested ions, only Cr3+ generated a significant fluorescence enhancement of up to 13-fold, which indicated the high selectivity of 1. Sensor (1) was successfully applied in the in vivo fluorescence imaging of Cr3+ in C. elegans. The results provided solid evidences for the future estimation of Cr3+ in environmental applications and tobacco samples. 相似文献
86.
聚丙烯酰胺(PA)水溶液的胶凝作用已成功地应用于油井堵水及二、三次采油的压裂工艺~[1].1979年Hessert等~[2]用Cr(Ⅵ)还原生成的Cr(Ⅲ)使PA交联成三维凝胶并用于采油,Terry等~[3]用稳态剪切粘度法对影响该过程动力学的因素作过研究.Prud'hornme等~[4]用流变模数随时间的变化来表征胶凝的速率.Sydansk~[5,6]对Cr(Ⅲ)使PA水溶液发生胶凝的速率及 相似文献
87.
Robert Glaum 《无机化学与普通化学杂志》1992,616(10):46-52
Contributions on the Thermal Behaviour of Anhydrous Phosphates. IX. Synthesis and Crystal Structure of Cr6(P2O7)4. A Pyrophosphate Containing Di- and Trivalent Chromium Cr6(P2O7)4 (Cr22+Cr43+(P2O7)4) can be obtained reducing CrPO4 by phosphorus (950°C, 48 h, 100 mg iodine as mineralizer). By means of chemical transport reactions (transport agent iodine; 1050 → 950°C) the compound has been separated from its neighbour phases (Cr2P2O7, CrP3O9) and crystallized (greenish, transparent crystals; edge length up to 0.3 mm). The crystal structure of Cr6(P2O7)4 (Spcgrp.: P-1; z = 1; a = 4.7128(8) Å, b = 12.667(3) Å, c = 7.843(2) Å, α = 89.65(2)°, β = 92.02(2)°, γ = 90.37(2) has been solved and refined from single crystal data (2713 unique reflections, 194 parameter, R = 0.035). Cr2+ is surrounded by six oxygen atoms which occupy the corners of an elongated octahedron (4 × dCr? O ≈? 2.04 Å; 2 × dCr? O ≈? 2.62 Å). The Cr3+ ions are also coordinated octahedraly (1.930 Å ≤ dCr? O ≤ 2.061 Å). The crystallographically independent pyrophosphate groups show nearly eclipsed conformation. The bridging angles (P? O? P) are 136.5° and 138.9° respectively. 相似文献
88.
We report here the low temperature emission spectra in the heterometal dinuclear 3d-4f assembled molecular system [(acac)2CrIII(μ-ox)LnIII(HBpz3)2] (Cr(ox)Ln:acac−=acetylacetonate, ox2−=oxalate, HBpz3−=hydrotris(pyrazol-1-yl)borate; Ln=La, Nd, Ho, Er , Tm and Yb) in comparison with those of Na[Cr(acac)2(ox)] and [(HBpz3)2Ln(μ-ox)Ln(HBpz3)2](Ln=Nd and Er). From 10 to 150 K the Cr(ox)Ln complexes show a broad emission band around 800 nm from the 2E state of Cr(III) moiety. At room temperature no 2E-4A2 emission was observed in the Cr(ox)Ln except for the La and Lu complexes. On warming from 10 to 300 K rapid quenching of the 2E-4A2 emission of Cr(III) is suggested to result from the energy transfer from Cr to Ln in the Cr(ox)Ln. The excitation spectra and the life-time were also measured with monitoring the 4f-4f emission peaks of the Cr(ox)Yb complex. 相似文献
89.
采用化学浸提技术对广东省黄埔港土壤中的铬进行了分析,研究了浸提条件及其对测定结果的影响,并运用GF-AAS法定量分析Cr(Ⅵ).检出限为0.03 μg/L,相对标准偏差(RSD,n=12)为1.52%,加标回收率在95.6%-103.6%. 相似文献
90.
An on-line flow injection (FI) preconcentration-electrothermal atomic absorption spectrometry (ETAAS) method is developed for trace determination of chromium in drinking water samples by sorption on a conical minicolumn packed with activated carbon (AC) at pH 5.0. The chromium was removed from the minicolumn with 1.0% (v/v) nitric acid. An enrichment factor (EF) of 35-fold for a sample volume of 10 ml was obtained. The detection limit (DL) value for the preconcentration method proposed was 3.0 ng l−1. The precision for 10 replicate determinations at the 0.5 μg l−1 Cr level was 4.0% relative standard deviation (R.S.D.), calculate with the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9992 at levels near the detection limits up to at least 50 μg l−1. The method was successfully applied to the determination of Cr(III) and Cr(VI) in drinking water samples. 相似文献