全文获取类型
收费全文 | 108篇 |
免费 | 6篇 |
专业分类
化学 | 65篇 |
力学 | 10篇 |
数学 | 2篇 |
物理学 | 37篇 |
出版年
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 3篇 |
2019年 | 15篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 14篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
1998年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1986年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有114条查询结果,搜索用时 700 毫秒
1.
Kolen'ko YV Kovnir KA Gavrilov AI Garshev AV Meskin PE Churagulov BR Bouchard M Colbeau-Justin C Lebedev OI Van Tendeloo G Yoshimura M 《The journal of physical chemistry. B》2005,109(43):20303-20309
Mesoporous nanosized TiO2 and Zn(x)Ti(1-x)O(2-x) solid solution having a Zn content below 10 mol % with a particles size between 13 and 17 nm are prepared by a template-free sol-gel method followed by high-temperature supercritical drying in 2-propanol. The structural, textural, and electronic properties of the obtained nanomaterials are methodically investigated by using XRD, SEM, TEM, ED, HREM, EDX, ICP-OES, N(2) adsorption-desorption, Raman spectroscopy, and diffuse reflectance UV-vis spectroscopy. It is shown that the proposed synthesis technique leads to the formation of a Zn(x)Ti(1-x)O(2-x) solid solution based on the anatase crystal structure rather than a two-phase sample. High-resolution electron microscopy and electron diffraction indicate that the distribution of zinc atoms over the anatase structure does not lead to a considerable deformation of the crystal structure. 相似文献
2.
The discolouration, that occurs in virgin poly(ethylene terephthalate) - PET during melt processing, was studied using various bulk and surface analytical techniques. Proton nuclear magnetic resonance (1H NMR) was used to study the bulk chemical changes occurring in the polymer during thermo-oxidative degradation. Chemical derivatisation with trifluoroacetic anhydride (TFAA) was used to label the hydroxyl groups introduced on the polymer surface by thermal oxidation.From the surface analysis studies using photoacoustic Fourier transform infrared spectroscopy (PA/FT-IR), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and X-ray photoelectron spectroscopy (XPS) it was evident that colour formation starts initially with the hydroxylation of the terephthalic ring. Further, the formation of additional carbonyl functionalities and conjugated chromophoric systems complete the colour formation process. 相似文献
3.
The thermal behaviour, molecular orientation and lateral diffusion in the bilayered systems of dimyristoylphosphatidylcholine (DMPC) in the presence of poly(ethylene oxide) (PEO) were studied by NMR and DSC techniques, and it was found that PEO decreases the melting temperature (of vesicles and flat multibilayers) and affects the degree of orientation of DMPC molecules relative to the bilayer normal, but it does not influence the lateral diffusion of DMPC molecules. 相似文献
4.
Supersonic flows of gas in the vicinity of the bottom region known as flows with sudden expansion have been considered. On the basis of extensive experimental studies, authors have proposed a complete classification of flow regimes: stationary, oscillating, and transient. Hysteresis of the regimes change at total gas pressure increasing and decreasing in front of the nozzle has been found. Typical shock-wave configurations emerging at the jet flowing in a channel at different modes have been determined. The type of shock-wave structure and the nature of interaction of the mixing layer of a jet with the wall or reverse flow flowing into the channel from ambient medium determine the appropriate mode. Combination of physical and numerical experiment with bottom pressure calculation according to the developed semi-empirical model have revealed new flow regimes that were not studied earlier. 相似文献
5.
6.
Flaviu Pop 《Central European Journal of Mathematics》2011,9(5):1088-1099
In this paper we consider a pair of right adjoint contravariant functors between abelian categories and describe a family
of dualities induced by them. 相似文献
7.
Bulat P. V. Volkov K. N. Grachev L. P. Esakov I. I. Lavrov P. B. 《Technical Physics》2021,66(11):1177-1185
Technical Physics - The development of efficient and reliable ignition systems for fuel mixtures is of interest for many practical applications associated with the use of combustion power plants.... 相似文献
8.
Bulat Munavirov Oleg Gnezdilov Maya Rudakova Oleg N. Antzutkin Andrei Filippov 《Magnetic resonance in chemistry : MRC》2013,51(11):750-755
Polyanion‐coated lipid vesicles are proposed to have an appreciable potential for drug delivery because of their ability to control the permeability of lipid bilayers by environmental parameters such as pH and temperature. However, details of the interaction of this class of polymers with lipids and their mechanisms of induced permeability are still being debated. In this work, we applied 1H NOESY to study details of the interaction of polyacrylic acid (PAA) fractions of molecular weights 5 and 240 kDa with dimyristoylphosphatidylcholine vesicles. We showed that PAA of two different molecular masses modifies lipid bilayers increasing disorder and probability of close contact between polar and hydrophobic groups. PAA molecules adsorb near the interface of lipid bilayers but do not penetrate into the hydrophobic core of the bilayer and, thus, cannot participate in formation of transbilayer channels, proposed in earlier works. Increasing the molecular mass of PAA from 5 kDa to 240 kDa does not change the effect of PAA on the bilayer, although PAA240 forms a more compact structure (either intra‐molecular or inter‐molecular) and interacts more strongly with interface lipid protons. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
10.
F. F. Bulat 《International Applied Mechanics》2006,42(9):967-975
The milestones in geotechnical mechanics research conducted at the N. S. Polyakov Institute of Geotechnical Mechanics of the
National Academy of Sciences of Ukraine are listed. Solutions to the deep-mining challenges faced by the institute as a leading
research institution in the industry are outlined. The basic results on the subject achieved by the institute over the years
of its existence are summarized
To the Beginning of the Third Millennium
To the 40th Anniversary of the N. S. Polyakov Institute of Geotechnical Mechanics
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 9, pp. 3–15, September 2006. 相似文献