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951.
铜钨杂多酸—耐尔蓝离子缔合显色反应及其应用 总被引:6,自引:0,他引:6
在阿拉伯胶存在下铜钨多酸与耐尔蓝形成离子缔子缔合物,其最大吸收位于580nm;表观摩尔吸光度ε值为2.22*10^6L.cm ^-1;铜量在0-24μg/L范围内服从比耳定律;检测限(3σ)1.0μg/L(n=10);分析16μg/L铜的RSD=1.5%(n=11);离子缔合物的摩尔比为Cu:W:NB=1:12:4。 相似文献
952.
Poly (azure blue II) (PABII) thin film modified electrode was successfully assembled on the surface of a glassy carbon electrode by means of electrochemical polymerization, which was carried out with cyclic voltammetric sweeping in the potential range of ‐ 0.6 to + 1.3 V (vs. SCE) in Britton‐Robinson buffer solution (pH = 9.8) containing 1.25 ± 10–4 mol/L azure blue II. The effect of pH on the polymerization process of azure blue II and the electrochemical characteristics of the polymer‐modified electrodes were studied in detail. The experimental results indicated that the electropolymerization of azure blue II could take place in basic or neutral media. The cyclic voltammograms of poly (azure blue II) thin film modified electrode showed the presence of two couples of redox peaks. The film modified electrode exhibited potent and persistent electrocatalysis for oxidation of dihydronicotiamide adenine dinucleotide (NADH) in phosphate buffer media with a diminution of the overpotential of about 410 mV and an increase in peak current. The presence of some divalent cations in an electrolyte can greatly enhance the electrocatalytic current for oxidation of NADH. The electrocatalytic current increased linearly with NADH concentration from 1.0 ± 10–5 to 8.0 ± 10–3 mol/L in the presence of 4.0 ± 10–2 mol/L Mg2+ cation. The detection limit (3sb1/S) was 5.0 ± 10–6 mol/L, and the relative standard deviation of determination results was 4.2% for six successive determinations of 5.0 ± 10–4 mol/L NADH in the presence of Mg2+ cation. 相似文献
953.
反相流动注射催化光度法测定亚硝酸根 总被引:2,自引:0,他引:2
采用反相流动注射技术与催化光度法相结合 ,研究了亚硝酸根在盐酸介质中催化溴酸钾氧化维多利亚蓝的灵敏褪色反应 ,用自制的微机化流动注射分析仪能准确控制时间 ,优化了试验条件 ,建立了测定痕量亚硝酸根的反相流动注射催化光度新方法。分析速度 36次·h- 1,克服了催化反应时间难以控制引起的方法精密度 ,准确度不高的弱点。亚硝酸根在 0 .0 0~ 2 .0 0mg·L- 1范围内 ,回归方程斜率为 0 .2 6 2。方法直接测定水中的亚硝酸根获得满意结果 相似文献
954.
A new spectroelectrochemical cell for slab optical waveguide (SOWG) spectroscopy was developed in order to observe in situ an electrode/electrolyte interface for bulk electrolysis. The new SOWG spectroelectrochemical cell has been evaluated by simultaneous electrochemical-absorption experiments of methylene blue (MB) using cyclic voltammetry (CV) and SOWG spectrometry. CV was performed in the SOWG spectroelectrochemical cell using indium tin oxide (ITO) coated glass as the working electrode, platinum wire as the counter electrode and a silver/silver chloride electrode (Ag/AgCl) as the reference electrode. Based on the CV and SOWG spectrometric data, it was found that the SOWG spectra showed the MB spectra on the electrode surface selectively and that SOWG with the cell would be useful as a tool for in situ study of an electrode/electrolyte interface. Using this cell, the effects of the supporting electrolytes, NaNO3, KNO3, CH3COONa, and CH3COOK on the absorbance of MB were examined at the potential of +0.8 V versus Ag/AgCl. The decrease in MB absorbance by nitrate ions was greater than that of acetate ions. Therefore the competitive adsorption of nitrate ions was stronger than that of acetate ions. Thus, the decrease in absorbance of MB in the presence of anions demonstrates the competitive adsorption of anions. These results show that the extent of specific adsorption of electrolytes was observed by measuring the SOWG absorbance intensity of MB. 相似文献
955.
《Electroanalysis》2006,18(18):1842-1846
Nanosized Prussian blue (PB) particles were synthesized with a chemical reduction method and then the PB nanoparticles were assembled on the surface of multiwall carbon nanotubes modified glassy carbon electrode (PB/MWNTs/GCE). The results showed that the PB/MWNTs nanocomposite exhibits a remarkably improved catalytic activity towards the reduction of hydrogen peroxide. Glucose oxidase (GOD) was immobilized on the PB/MWNTs platform by an electrochemically polymerized o‐phenylenediamine (OPD) film to construct an amperometric glucose biosensor. The biosensor exhibited a wide linear response up to 8 mM with a low detection limit of 12.7 μM (S/N=3). The Michaelis–Menten constant Km and the maximum current imax of the biosensor were 18.0 mM and 4.68 μA, respectively. The selectivity and stability of the biosensor were also investigated. 相似文献
956.
The use of thin films of Prussian blue and heterogeneous Prussian blue membranes as potassium ion-selective electrodes was investigated. All of the heavier group I cations and NH+4 interfere strongly but there is relatively good selectivity towards Na+ with a selectivity coefficient of ca. 5 × 10?3. The thin-film measurements, based on Prussian blue deposited on platinum, involve conditioning the electrode to a fixed potential according to the method used by Engel and Grabner for copper hexacyanoferrate(III) films. The membrane electrodes were based on mixing Prussian blue with polymeric supporting films such as polystyrene and epoxy. A particularly simple practical configuration involves Prussian blue membranes deposited directly on copper conductors where one membrane serves as a reference electrode. A reversible cell, without liquid junction, is formed with Prussian blue and Ag/AgCl electrodes and this serves as a means for determining an accurate value for the standard reduction potential of Prussian blue, which is found to be 0.238 V vs. Ag/AgCl at 25 °C. 相似文献
957.
高稳定性普鲁士蓝修饰电极的制备和研究 总被引:4,自引:0,他引:4
采用恒电流电解方法,使用FeCl_3-K_3Fe(CN)_6和Fe~(?)L_(?) -K_3Fe(CN)_6(L,邻菲绕啉,EDTA,5-磺基水杨酸等)两体系,在玻碳和铂基体上均制得高稳定性普鲁士蓝膜。用循环伏安法在lmol·dm~(-3)KCl(pH4)溶液中,重点地在0.6--1.1V(vs.Ag/AgCl)区间研究了膜的电化学稳定性。在玻碳基体上FeCl_3,-K_3Fe(CN)_6和Pe~(?)·L_(?) -K_3Fe(CN)_6体系电积膜分别可经受10~(?)周和2×10~(?)周扫描。在铂基体上则可分别经受2×10~(?)和7×10~(?)周扫描。红外和X-射线衍射证明两体系制得的膜均为普鲁士蓝膜,稳定性的明显差异是由于普鲁士蓝晶粒度的不同和在基体表面的相对取向不同引起的。对影响膜的稳定性的因素作了较系统的研究。 相似文献
958.
959.
960.
阻抑聚丙烯酰胺催化蛋白质-亚甲基蓝褪色光度法测定痕量铋 总被引:3,自引:0,他引:3
在加热条件下,基于Bi(Ⅲ)对聚丙烯酰胺(PAM)催化蛋白-亚甲基蓝(MB)褪色反应有强的抑制作用,建立了动力学光度法测定铋的新方法。△A与CBi(Ⅲ)呈线性关系的范围为0.08-0.48μg/L;检出限为0.004μg/L;对0.04和0.040μgBi(Ⅲ)/L测定的RSD分别为6.4%一2.6%,本阻抑-催化褪色反应对Bi(Ⅲ)、蛋白质-亚甲基蓝和PAM为一级反应,表观活化能为49.22kJ/mol.该方法已用于某些谷物,人发和水样中Bi(Ⅲ)的测定。结果满意。 相似文献