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81.
Electrodeposition of nanocrystalline zinc from acidic sulfate solutions containing thiourea and benzalacetone as additives 总被引:1,自引:0,他引:1
Mou Cheng Li Li Li Jiang Wen Qi Zhang Yu Hai Qian Su Zhen Luo Jia Nian Shen 《Journal of Solid State Electrochemistry》2007,11(4):549-553
Nanocrystalline zinc coatings were produced by pulse electrodeposition in acid sulfate bath containing thiourea and benzalacetone
additives and characterized by X-ray diffraction and scanning electron microscopy techniques. The influence of benzalacetone
concentration and pulse peak current density on the grain size and crystallographic orientation of zinc deposits was investigated.
Zinc electrodeposited from additive-free solutions or with one of the two additives is not composed of nanosized crystals.
The mixture additives of thiourea and benzalacetone give rise to the formation of particle-like nanocrystalline zinc with
a (10ī1) random orientation. A change in peak current density from 2 to 1 A/cm2 only increases the grain size from 60 to 62 nm. 相似文献
82.
83.
从氨性柠檬酸溶液中电沉积Ni-Mo的机理研究 总被引:6,自引:1,他引:6
含钼大于约27%(质量分数)Ni-Mo合金,具有较高的耐蚀性,特别是在盐酸和硫酸溶液中,其耐蚀性优于SUS304不锈钢[1].因此,人们对该种合金的电沉积进行了广泛的研究[1-4].对合金共沉积机理也作了一定的研究.一般认为,钼不能单独进行电沉积,但它可以同铁族元素共沉积[5].对钼与铁族元素的共沉积机理,人们已提出了几种假设.一般认为[3],钼可能是多步还原,即六价钼首先被电化学还原成低价钼化合物,而后由吸附在诱导金属(铁族元素)上的原子氢进一步还原成合金中的零价钼,为了进一步弄清Ni-Mo合金的共沉积机理,本… 相似文献
84.
用循环伏安法和电位阶跃法研究了LiCl-KCl-NaCl熔盐体系中碳的阴极还原机理。在钨、铂、不锈钢等微电极上得到的伏安图表明碳的还原是由CO_3~(2-)离子经一步电化学反应实现的,电极反应速度控制步骤为CO_3~(2-)离子向阴极的扩散过程,还原过程具有反应物吸附特征。碳在W、Pt、不锈钢电极上析出电位分别为-2.05V、-1.745V和-1.90V(均相对于Ag/AgCl参比电极)。 相似文献
85.
The electrochemistry of indium species was investigated at glassy carbon, tungsten and nickel electrodes in a basic 1‐ethyl‐3‐methylimidazolium chloride/tetrafluoroborate ionic liquid. Amperometric titration experiments suggest that In(III) chloride is complexed as [InCl5]2? in this ionic liquid. The electrochemical reduction of [InCl5]2? to indium metal is preceded by overpotential driven nucleations. The effective anodic dissolution of indium to indium(III) requires, however, the presence of sufficient chloride ions at the electrode surface. The electrodeposition of indium at glassy carbon and tungsten electrodes proceeds via three‐dimensional instantaneous nucleation with diffusion‐controlled growth of the nuclei. At the nickel electrode, the deposition proceeds via three‐dimensional progressive nucleation with diffusion‐controlled growth of the nuclei. Raising the deposition temperature decreases the average radius of the individual nuclei, r. Scanning electron microscopic and x‐ray diffraction data indicated that bulk crystalline indium electrodeposits could be prepared on nickel substrates within a temperature range between 30 and 120 °C. 相似文献
86.
Fractal dimension of a carious tooth surface was determined using an electrochemical method. The method was based on time-dependent diffusion towards electrode surfaces, which is one of the most useful and reliable methods for the determination of fractal dimension of electrode surfaces. For this purpose, the tooth was covered with a gold layer, which acted as an electrode in electrochemical experiments. It is suggested that the fractal dimension can be used as a quantitative measure of the state of dental surfaces. The method presented demonstrates the power of electrochemical techniques for the determination of fractal dimension of surface of non-conducting objects. 相似文献
87.
镀液中Ce^3+离子对锡镀层结构缺陷和可焊性的影响 总被引:1,自引:0,他引:1
应用荧光分析法、X光电子能谱法(XPS)及正电子湮没寿命谱法(PALS)等研究了从含硫酸铈添加剂的酸性光亮锡镀液获得的锡镀层结构缺陷与可焊性的关系。结果表明,电镀时Ce与Sn不发生共沉积,Ce~(3+)的主要作用是阻化Sn~(2+)的水解和氧化使镀液稳定,因而使锡镀层纯度提高、结构致密、表层氧含量减少,有利于提高镀层的可焊性。当Ce~(3+)浓度控制在3.5g/L左右时,可使镀层结构缺陷较少,可焊性较佳,说明结构缺陷是影响锡镀层可焊性的直接原因。 相似文献
88.
89.
Electrodeposition of fluorine-doped lead dioxide 总被引:3,自引:0,他引:3
The electrocatalytic properties of PbO2 may be increased by incorporation of some ions such as F−. In this review, the preparation of fluorine-doped PbO2 in the presence of some additives of fluorine-containing compounds (F−, potassium salt of nonafluoro-1-butanesulfonic acid C4F9O3SK and Nafion®) is reported. The mechanism of electrodeposition is discussed. The amount of additives in the deposit depends on the experimental conditions: potential, current density and charge of additive species in the plating solution. The physicochemical properties of doped oxide are very different from those of undoped oxide, accounting for the different electrocatalytic activity of the materials. 相似文献
90.
本工作利用微循环伏安法和阶跃电位法研究在AuCl3的酸性溶液中金在玻碳和铂微电极上的电沉积行为。结果表明,金在微电极上成核所需的过电位较高,但成核几率也高,在所研究的微电极尺寸范围内,金可形成大量的临界单核,且核的生长速率很快。铂微电极上金电沉积的I-t曲线符合连续成核的模式。 相似文献