全文获取类型
收费全文 | 169篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 104篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 50篇 |
物理学 | 15篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 15篇 |
2012年 | 11篇 |
2011年 | 12篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1973年 | 1篇 |
1927年 | 3篇 |
1926年 | 2篇 |
排序方式: 共有172条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
The study of electrogenerated chemiluminescence (ECL) in aqueous and non-aqueous media with tetraphenylborate anion as a co-reactant is reported. The obtained results indicate that tetraphenylborate acts according to an oxidative reduction scheme and forms a strong reducer after being homogeneously oxidized by a radical cation or dication of luminophore. Spectral measurements prove that light emission originates from the luminophore present in solution and practically no emission occurs when only tetraphenylborate ion is oxidized at the electrode. Since the tetraphenylborate ion is a well known analytical reactant and precipitates a number of metal and organic cations its electrochemiluminescent detection can be used for their assay. It can also be applied as an efficient co-reactant for electrogenerated chemiluminescence excitation both in aqueous and non-aqueous media. 相似文献
55.
Nazariy T. Pokhodylo Vasyl S. Matiychuk Mykola D. Obushak 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):850-858
Abstract Two synthetic pathways for the preparation of 2-mercapto-3-arylpropanoic acids were developed. First, by the reaction of arenediazonium bromides with acrylic esters in the presence of CuBr, alkyl (2-bromo-3-aryl)propanoates were formed. Their cyclization with thiourea produced 5-(R-benzyl)-2-imino-4-thiazolidinones, which yielded 3-aryl-2-mercaptopropanoic acids by alkaline hydrolysis. Second, direct Meerwein arylation of acrylates in the presence of S-nucleophile (NaSH) allowed isolation of 3-phenyl-2-mercaptopropanoic acid in 8% yield. Such acids were used for cyclization with cyanoguanidine and phenyl isothiocyanate yielding 1-[5-(R-benzyl)-4-oxo-1,3-thiazolidin-2-ylidene]guanidines and new 5-(R-benzyl)-3-phenyl-2-thioxo-1,3-thiazolidin-4-one (rhodanine) derivatives correspondingly. 相似文献
56.
Periodica Mathematica Hungarica - We give a simple construction involving partial actions which permits us to obtain an easy proof of a weakened version of L. O’Carroll’s... 相似文献
57.
Yu. A. Kabachii S. Yu. Kochev S. S. Abramchuk A. S. Golub P. M. Valetskii O. Yu. Antonova Yu. N. Bubnov V. A. Nadtochenko 《Russian Chemical Bulletin》2017,66(11):2048-2056
Nanocrystals (NCs) of CdS with oleate surface (NC-1) and octadecyl thiolate surface (NC-2), stabilized by a polycation shell, were doped with nickel bis(2-aminobenzenethiolate) (1), cobalt(III) chlorobis(dimethylglyoximato)(2-mercaptopyridine) (2), and also with 1,2-ethanedithiol and didodecylsulfide clathrochelates of cobalt(II) (3 and 4). The influence of doping on the photocatalytic activity in the hydrogen evolution reaction was investigated. Complex 1 appeared to be the most effective cocatalyst for H2 evolution with the reaction rate increased by the factor of 8—11. Accomodating the complex in a polymer shell yields the best result. The rate of H2 evolution increases monotonically with increasing concentration of this complex until the concentration achieves the ratio of one complex molecule per single NC. It is shown that the chemical composition of the surface has a significant influence on their photocatalytic activity in the hydrogen evolution reaction. The activity of NC-2 is 200 times that of NC-1. The replacement of oleate groups of the latter with sulfide increases the activity of these photocatalysts by a factor of 2000. 相似文献
58.
AbstractThe purpose of this paper is to provide new experimental data for high-strength VT 22 titanium α + β-type alloy under impact-oscillatory loading and dynamic non-equilibrium process. Based on the performed experimental studies, it was found that overall plastic deformation of this alloy can be increased by a factor 2.75 compared with its initial state without significant loss of strength. To achieve this goal, a new methodology to study the impact behaviour of materials under non-equilibrium process has been used. Physical research revealed that significant microstructural refinement of the alloy is observed after such type of loading, as the result of which the fine grains are formed with subgrain refinement which takes place within the basis of alloy. 相似文献
59.
I. A. Aleksandrov I. Yu. Metlenkova S. S. Abramchuk S. P. Solodovnikov A. A. Khodak S. B. Zezin A. I. Aleksandrov 《Technical Physics》2013,58(3):375-379
The objects of investigation are polystyrene-based composites with ultradisperse particles (including nanoparticles) of metallic Gd and SiO2. The composites prepared by milling starting materials in a barrel mill at room temperature are studied by the ferromagnetic resonance method, transmission electron microscopy (TEM), and reflection X-ray diffraction (RXD). It is found that the magnetic subsystem of the composites is formed by magnetic nanoclusters, Gd crystallites 30 ± 10 nm across, which possess volume and surface magnetic anisotropy and pass into the superparamagnetic state at 210 ± 10 K. It is also found that the Landau-Lifshitz equation with the damping term in the Landau-Lifshitz form provides the best quantitative fit to experimental data for the ferromagnetic resonance of superparamagnetic metal nanoparticles. 相似文献
60.
Ezhov AA Shandryuk GA Bondarenko GN Merekalov AS Abramchuk SS Shatalova AM Manna P Zubarev ER Talroze RV 《Langmuir : the ACS journal of surfaces and colloids》2011,27(21):13353-13360
We report on the structure, uniaxial orientation, and photoluminescent properties of CdS nanorods that form stable nanocomposites with smectic C hydrogen-bonded polymers from the family of poly(4-(n-acryloyloxyalkoxy)benzoic acids. TEM analysis of microtomed films of nanocomposites reveals that CdS nanorods form small domains that are homogeneously distributed in the LC polymer matrix. They undergo long-range orientation with the formation of one-dimensional aggregates of rods when the composite films are uniaxially deformed. The Stokes photoluminescence was observed from CdS NRs/LC polymer composites with emission peak located almost at the same wavelength as that of NRs solution in heptane. An anti-Stokes photoluminescence (ASPL) in polymer nanocomposites was found under the excitation below the nanoparticles ground state. The mechanism of ASPL was interpreted in terms of thermally populated states that are involved in the excitation process. These nanocomposites represent an unusual material in which the optical properties of anisotropic semiconductor nanostructures can be controlled by mechanical deformation of liquid-crystalline matrix. 相似文献