全文获取类型
收费全文 | 131篇 |
免费 | 5篇 |
专业分类
化学 | 85篇 |
晶体学 | 3篇 |
数学 | 18篇 |
物理学 | 30篇 |
出版年
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 15篇 |
2012年 | 14篇 |
2011年 | 13篇 |
2010年 | 12篇 |
2009年 | 2篇 |
2008年 | 8篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1995年 | 1篇 |
1989年 | 1篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有136条查询结果,搜索用时 62 毫秒
101.
S. M. Lukyanov Yu. E. Penionzhkevich D. Guillemaud-Mueller M. Lewitowicz R. Anne R. Astabatyan D. Baiborodin C. Borcea A. Buta F. de Oliveira Santos Z. Dlouhý G. Faivre S. Grevy G. Georgiev F. Ibrahim S. Lobastov I. Matea J. Mrazek A. C. Mueller F. Negoita F. Pougheon O. Perru Yu. G. Sobolev I. Stefan D. Verney 《Physics of Atomic Nuclei》2003,66(9):1639-1642
The neutron drip line in the neon-magnesium region has been explored by the projectile fragmentation of a 48Ca(59.8 A MeV) beam using the new fragment separator LISE-2000 at GANIL. New neutron-rich isotopes, 34Ne and 37Na, have been observed together with some evidence for the particle instability of 33Ne and 36Na. 相似文献
102.
Raluca Nicoleta Darie Ruxandra Bodirlau Carmen Alice Teaca Joanna Macyszyn Marek Kozlowski Iuliana Spiridon 《International Journal of Polymer Analysis and Characterization》2013,18(4):315-327
In the view of producing environmentally friendly materials without compromising properties, new composites containing polypropylene as a matrix and eucalyptus wood, with or without 15% of polylactic acid, were melt processed. In order to improve compatibility between components, a chemical modification of wood with toluene-2,4-diisocyanate (TDI) was realized and evidenced by changes in FT-IR and XPS spectra. The morphological, mechanical, and thermal characterizations of the obtained composites were evaluated before and after accelerating weathering. The results showed that the material comprising 15% TDI-modified wood, PP, and 15% PLA exhibited the best properties. 相似文献
103.
Maria Geba Gabriela Lisa Cristina Marta Ursescu Angelica Olaru Iuliana Spiridon Ana Lacramioara Leon Ioana Stanculescu 《Journal of Thermal Analysis and Calorimetry》2014,118(2):977-985
In order to investigate the effect of gamma rays on cultural heritage materials, samples of silk and wool fabrics were subjected to accelerated ageing testing and then irradiated with different gamma-ray doses: 10 and 25 kGy. In the data analysis, combining thermal analysis (TG and DTG), infrared spectroscopy (FTIR-ATR) and mechanical tests allowed us to explore the changes in physical and chemical features for silk and wool, in relationship to the radiation doses. This analytical protocol offers a way to examine the behaviour of the textiles made of wool and silk within museum collections and their response to gamma-rays irradiation treatment. An exposure to a dose of 10 kGy did not cause significant changes in the tested properties; however, higher doses initiated irreversible loss in the physical and chemical stability of protein-based fabrics. Increasing the irradiation dose above 10 kGy has drastic effects in the loss of elasticity and the mechanical resistance of the tested yarns. 相似文献
104.
We obtain explicit upper bounds for the number of irreducible factors for a class of polynomials of the form f ○ g, where f,g are polynomials with integer coefficients, in terms of the prime factorization of the leading coefficients of f and g, the degrees of f and g, and the size of coefficients of f. In particular, some irreducibility results are given for this class of compositions of polynomials. 相似文献
105.
Mihaela Alexandru Maria Cazacu Alexandra Nistor Valentina E. Musteata Iuliana Stoica Cristian Grigoras Bogdan C. Simionescu 《Journal of Sol-Gel Science and Technology》2010,56(3):310-319
Composites based on polydimethylsiloxane incorporating silica and titania were prepared by mixing polydimethylsiloxane with
proper oxides precursors, tetraethyl-orthosilicate and tetrabutyl-orthotitanate. In the presence of environmental humidity
and in acid catalysis, hydrolysis/condensation processes take place with formation of oxides and concomitantly polymer crosslinking.
Partial replacement of SiO2 in a polydimethylsiloxane/silica composite with titania (both generated in situ by sol–gel process) affects surface hydrophilicity
(evaluated by dynamic contact angle), water vapor sorption ability (determined by dynamic vapor sorption) and thermal stability.
The dielectric properties are also controlled by composition. 相似文献
106.
107.
Sendroiu IE Mertens SF Schiffrin DJ 《Physical chemistry chemical physics : PCCP》2006,8(12):1430-1436
The effects of interparticle distance on the UV-visible absorption spectrum of gold nanocrystals aggregates in aqueous solution have been investigated. The aggregates were produced by ion-templated chelation of omega-mercaptocarboxylic acid ligands covalently attached to the nanoparticles surface. Variation of the ligand chain length provides control over the interparticle separation in the aggregates. The UV-visible spectra consist typically of a single particle band and a secondary band at higher wavelengths associated with the formation of aggregates in solution. The position of the latter depends on interparticle separation up to distances of approximately 8 nm, in accordance with existing models. Potential applications therefore include distance sensitive labels or proximity probes. Conversely, variation of the ligand length allows the preparation of nanostuctured materials with tuned optical properties. 相似文献
108.
The infrared absorption properties of a-SiC:H thin films dependence with the dc magnetron power density were investigated. The films were deposited in a mixture of CH4, H2 and Ar. The target used was polycrystalline Si. We found that the dc magnetron power density has an important contribution to the film composition. There is a strong dependence of the Si-H and Si-C bonds with the dc power density. 相似文献
109.
We demonstrate that nonlinear electrical transport through a two-terminal nanoscale sample is not symmetric in the magnetic field B. More specifically, we have measured the lowest order B-asymmetric terms in single-walled carbon nanotubes. Theoretically, these terms can be used to infer both the strength of electron-electron interactions and the handedness of the nanotube. Consistent with theory, we find that at high temperatures the B-linear term is small and has a constant sign independent of Fermi energy, while at low temperatures it develops mesoscopic fluctuations. We also find surprising magnetoresistance at zero bias in the metallic regime. 相似文献
110.
In 1994 Butov et al. [Phys. Rev. Lett. 73, 304 (1994)] reported large, extremely low-frequency fluctuations in the luminescence intensity from indirect excitons in a coupled quantum well. We have reproduced these fluctuations in a similar structure. Our observations indicate, however, that the fluctuations are spectral fluctuations rather than intensity fluctuations. We have eliminated several possible causes for the fluctuations and propose a possible cause. 相似文献