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811.
β‐Cyclodextrin Incorporated Carbon Nanotube Paste Electrode as Electrochemical Sensor for Nifedipine
In this work a carbon paste electrode modified with multiwalled carbon nanotubes/β‐cyclodextrin (MWCNTs/β‐CD) was constructed and applied to the determination of nifedipine. The electrochemical behavior of nifedipine at this electrode was investigated using cyclic voltammetry and differential pulse voltammetry. Characterization of the modified electrode was conducted with electrochemical impedance spectroscopy and scanning electron microscopy. After adsorption of nifedipine on the MWCNTs/β‐CD paste electrode at 0.0 V for 6 min, a well defined reduction peak was produced in sodium hydroxide of 0.05 M. The calibration curve was linear from 7.0×10?8 to 1.5×10?5 M. The detection limit was obtained as 2.5×10?8 M. The results demonstrated that this electrochemical sensor has excellent sensitivity and selectivity. This sensor was applied for determination of nifedipine in drug dosage and blood serum with excellent recoveries. 相似文献
812.
首先制备出量子点(QDs)/TiO2涂料,分别采用丝网印刷法与刀刮法将涂料涂覆于ITO/PET柔性基底上,结果表明刀刮法制备量子点敏化太阳电池(QDSCs)效果更佳,且具有普适性。基于铜片对电极所组装的ZnCuInSe,CdSe和CdSeTe量子点半柔性QDSCs最高效率分别达2.83%,2.46%和1.99%。另外,我们对石墨纸进行表面化学修饰以提高亲水性,再通过简单的连续离子交换吸附法(SILAR)在石墨纸上负载CuxS纳米粒子,制备出CuxS/GP柔性对电极,进一步组装成全柔性QDSCs,获得了2.13%光电转化效率。 相似文献
813.
Cu2+-mediated salbutamol-imprinted polymer nanoparticles, synthesized by precipitation polymerization, were mixed with graphite powder and n-eicosane in order to fabricate a modified carbon paste electrode. This electrode was then applied for indirect differential pulse voltammetry determination of salbutamol. In the presence of Cu2+ ions, the formed Cu2+–salbutamol complex was adsorbed in to the pre-designed cavities of the MIP particles, situated on the electrode surface. Since the electrochemical signal of salbutamol was intrinsically small, the oxidation peak of the participant Cu2+, after reduction step, was recorded and used as an indication of salbutamol amount, adsorbed in the electrode. Different variables influencing the sensor performance were studied and the best conditions were chosen for the determination purpose. Correlation between the sensor response to salbutamol and its concentration was linear in the range of 1.0 × 10−9–5.5 × 10−8 M. Detection limit was calculated equal to 6.0 × 10−10 M (S/N). Five replicated determination of salbutamol (1 × 10−8 M) resulted in standard error of 3.28%, meaning a satisfactory precision of the determination method. The prepared sensor was applied for real sample analysis. In order to minimize the interference effect, the synthesized polymer was successfully used as a solid phase sorbent for salbutamol extraction, before analysis of real samples by the developed sensor. 相似文献
814.
In this paper, nichrome was adopted as a substrate, to fabricate the pre‐anodized inlaying ultrathin carbon paste electrode (PAIUCPE). The electrochemical behaviors and diffusion mechanisms of three dihydroxybenzene isomers at the electrode were carefully investigated. The effect of pH on oxidation peak current was also detailedly explained. The results were shown that oxidation peak current not only related to the reaction of electroactive materials at the working electrode, but also depended on the reaction variable of reduction at the auxiliary electrode. The oxidation peaks of hydroquinone (HQ), catechol (CC) and resorcinol (RC) located at 0.181 V, 0.288 V and 0.736 V. For CC, RC and HQ, the oxidation peak currents were linear to the concentrations at the range of 5.0 × 10?6~5.0 × 10?4 mol/L, 3.0 × 10?6~5.0 × 10?4 mol/L and 4.0 × 10?6~4.0 × 10?4 mol/L with the detection limits of 2.0 × 10?7 mol/L, 1.2 × 10?7 mol/L and 1.2 × 10?7 mol/L, respectively. The proposed method was successfully applied in the simultaneous determination of dihydroxybenzene isomers in artificial sewage samples with satisfactory results. 相似文献
815.
A carbon paste electrode was used for the electrochemical determination of linuron concentrations in water and vegetable extracts. Optimal conditions were established with respect to electrode activation (electrochemical pretreatment), time accumulation, potential accumulation, scan rate, and pH. The limit of detection achieved with a pre-concentration step was 23.0 μg L−1. Recovery measurements in vegetable extract and natural water samples were in the range of 98-103%, indicating that the proposed electrochemical method can be employed to analyze linuron in these matrices. The determination results were in good agreement with HPLC results. 相似文献
816.
817.
超高效液相色谱-串联质谱法快速检测番茄酱中吡虫啉等6种农药残留 总被引:4,自引:0,他引:4
建立了番茄酱中吡虫啉、多菌灵、甲基硫菌灵、霜霉威、灭多威和烯酰吗啉等农药残留的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。样品用含0.1%(体积分数)乙酸的甲醇-水(1:1, v/v)混合溶液提取,采用Waters Acquity UPLC BEH C18色谱柱,以甲醇和10 mmol/L乙酸铵溶液为流动相进行梯度洗脱分离,经电喷雾正离子(ESI+)电离及多反应监测(MRM)模式来测定目标化合物,采用基质标准溶液曲线法进行定量。结果表明: 6种农药在0.005~0.2 mg/L的范围内线性关系良好(r>0.995);当标准添加水平为0.02、0.05和0.2 mg/kg时,回收率为66.8%~102.9%;相对标准偏差均小于15%; 6种农药的定量限(以信噪比(S/N)>10计)均为0.02 mg/kg。该方法简便、快速、灵敏和准确,非常适合番茄酱中这6种农药残留的快速检测及定量分析。 相似文献
818.
A novel strategy for preparing highly sensitive and easily renewable molecularly imprinted polymer (MIP) sensors was proposed. Using melamine (MA) as the template molecule, MIP particles were synthesized and embedded in a solid paraffin carbon paste to prepare the MIP sensor. MA was indirectly determined from the competition between the reactions of MA and horseradish peroxidase-labeled MA (MA-HRP) with the vacant cavities. The detection signals were amplified because of enzymatic reaction to the H2O2 catalytic oxidation. Sensitivity was markedly improved. Sensor renewal was achieved by a simple mechanical polishing of the sensitive film. The linear range for MA detection was 0.005–1 μmol L−1 and the detection limit was 0.7 nmol L−1. The molecularly imprinted solid paraffin carbon paste sensor was used for MA detection in milk samples. 相似文献
819.
本文制备了离子液体-Ni微/纳米粒子修饰碳糊电极.研究了离子液体对Ni微/纳米粒子氧化还原的促进作用,用循环伏安法在0.1 mol/L B-R缓冲溶液(pH=4.5)中研究了维生素B2(VB2)在该修饰电极上的电化学行为,优化了各种实验条件.实验结果表明,本文制备的修饰电极能很好地催化氧化VB2,VB2在该修饰电极上的... 相似文献
820.
Mohammad Bagher Gholivand Behrooz Geravandi Mohammad Hadi Parvin 《Electroanalysis》2011,23(6):1345-1351
A differential pulse anodic stripping voltammetric procedure was developed for the determination of trace amounts of iron(II) in the presence of iron(III) at a carbon paste electrode (CPE) modified with dithiodianiline and gold nanoparticle. At the pH working of 3.0, a wide concentration range from 0.1 nM to 100 nM was observed with the detection limit of 0.05 nM. The relative standard deviation for a solution containing 50 nM of iron(II) was found to be 3.11 % (n=9). Possible interferences from the coexisting ions were also investigated. The validity of the method and applicability of the sensor were successfully tested by determining of iron(II) in lentil, wheat seed and barley seed samples. 相似文献