全文获取类型
收费全文 | 325篇 |
免费 | 8篇 |
专业分类
化学 | 251篇 |
力学 | 7篇 |
数学 | 21篇 |
物理学 | 54篇 |
出版年
2023年 | 2篇 |
2022年 | 24篇 |
2021年 | 22篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 20篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 22篇 |
2012年 | 19篇 |
2011年 | 26篇 |
2010年 | 17篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2000年 | 2篇 |
1997年 | 2篇 |
1992年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 3篇 |
1968年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有333条查询结果,搜索用时 0 毫秒
41.
E. V. Chernikova N. S. Serkhacheva O. I. Smirnov N. I. Prokopov A. V. Plutalova E. A. Lysenko E. Yu. Kozhunova 《Polymer Science Series B》2016,58(6):629-639
The effect of the chain length of oligomer acrylic acid obtained in the presence of a low-molecularmass trithiocarbonate and the position of trithiocarbonate fragment (within the chain or at the chain end) on the process of emulsion polymerization of n-butyl acrylate and characteristics of the resulting dispersions has been studied for the first time. It has been found that, when using an oligomer with trithiocarbonate group located within the chain in the emulsion polymerization of n-butyl acrylate in a wide range of monomer–water phase compositions, triblock copolymers self-organizing in aqueous medium to give stable particles with the core–shell structure are formed. Oligomers with M n ~ (5–10) × 103 are optimal for synthesis of stable dispersions. In this case, block copolymers with the controlled length of hydrophobic block and a rather narrow MWD may be obtained. Thin films formed from these copolymers retain the structure of the initial dispersions on solvent removal. If the trithiocarbonate group in the oligomer is located at the chain end, the main polymerization product is a diblock copolymer. In this case, the formation of polymer–monomer particles occurs during a longer period of time, the control of MWD is weakened, and the dispersions of particles lose the aggregative stability after thin film formation. 相似文献
42.
Michał Mosiałek Magdalena Dudek Aneta Michna Maciej Tatko Aneta Kędra Małgorzata Zimowska 《Journal of Solid State Electrochemistry》2014,18(11):3011-3021
Silver-Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) cathodes were prepared in two ways. In the first method, Ag-BSCF composite powder was prepared in ethanol solution, where Ag nanoparticles serving as a component in the preparation of Ag-BSCF composite cathodes had been previously obtained via one-step synthesis in absolute ethanol using a neutral polymer (polyvinylpyrrolidone). To the best of our knowledge, this is the first study to use a Ag sol obtained by the above method for preparation of Ag-BSCF composite powder. Then, a paste containing this powder was screen-printed on a Sm0.2Ce0.8O1.9 electrolyte and sintered at 1,000 °C. In the second technique, an aqueous solution of AgNO3 was added to a previously sintered BSCF cathode, which was then sintered again at 800 °C. The oxygen reduction reaction at the quasi-point BSCF cathode on the Sm0.2Ce0.8O1.9 electrolyte was tested by electrochemical impedance spectroscopy at different oxygen concentrations in three electrode setup. The continuous decrease of polarization resistance was observed under polarization ?0.5 V at 600 °C. The comparative studies of both obtained composite Ag-BSCF materials were performed in hydrogen-oxygen IT-SOFC involving samaria-doped ceria as an electrolyte and Ni-Gd0.2Ce0.8O1.9 anode. In both cases, the addition of silver to the cathode caused an increase in current and power density compared with an IT-SOFC built with the same components but involving a monophase BSFC cathode material. 相似文献
43.
We study static, spherically symmetric equilibrium configurations in extended theories of gravity (ETG) following the notation introduced by Capozziello et al. We calculate the differential equations for the stellar structure in such theories in a very generic form i.e., the Tolman–Oppenheimer–Volkoff generalization for any ETG is introduced. Stability analysis is also investigated with special focus on the particular example of scalar–tensor gravity. 相似文献
44.
45.
Prokopov A. R. Mikhailova T. V. Danishevskaya E. V. Shaposhnikov A. N. Berzhansky V. N. Karavainikov A. V. Nedviga A. S. Nauhatsky I. A. Milyukova E. T. 《Technical Physics》2019,64(11):1709-1715
Technical Physics - We present the results of studies on the optimization of the synthesis of Bi-substituted iron garnet (Bi : IG) films by liquid-phase epitaxy and vacuum deposition followed by... 相似文献
46.
Prokopov V. A. Alexeyev S. O. Zenin O. I. 《Journal of Experimental and Theoretical Physics》2022,135(1):91-99
Journal of Experimental and Theoretical Physics - The first images of black hole shadows open new possibilities to constrain modern extended gravity theories. We present the method of shadow... 相似文献
47.
In the paper we propose a modification of the classical construction of the (Minkowskian) incidence structures based on permutation groups. Dropping out explicit assumptions concerning rigidity and transitivity (and assuming an arbitrary finite ”dimension”) we obtain a wider class of structures. Their geometrical properties are studied; in particular, we establish their automorphism groups and discuss some problems related to axiomatic characterization. 相似文献
48.
The influence of the temperature and time of heating during dissolution on the aging of concentrated aqueous solutions of poly(vinyl alcohol) and aging at different temperatures are described. Changes occuring during aging are interpreted on the basis of non-Newtonian viscosity and normal stress measurements. 相似文献
49.
Chemical vapor deposition (CVD) method was used in titania surface modification. Titania layers were obtained in sol-gel process and prepared as thin films on silicon wafers in dip-coating method. In order to define the influence of modification on titania surface properties (e.g., friction), various types of fluoroalkylsilanes were used. The effectiveness of the modification was monitored by FT-IR spectroscopy. The topography and frictional measurements were investigated with the use of atomic force microscopy (AFM). 相似文献
50.