全文获取类型
收费全文 | 73篇 |
免费 | 0篇 |
专业分类
化学 | 16篇 |
数学 | 20篇 |
物理学 | 37篇 |
出版年
2020年 | 2篇 |
2019年 | 2篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2013年 | 2篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2008年 | 3篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1999年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1991年 | 1篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1962年 | 1篇 |
1936年 | 1篇 |
1862年 | 1篇 |
排序方式: 共有73条查询结果,搜索用时 31 毫秒
1.
Zaharescu M. Jitianu A. Brăileanu A. Madarász J. Novák CS. Pokol G. 《Journal of Thermal Analysis and Calorimetry》2003,71(2):421-428
Hybrid materials with different amounts of organics permanently bound on the inorganic network obtained in the TEOS-MTEOS
(tetraethoxysilan-methyltriethoxysilan) system are used for obtaining coatings with different optical and mechanical properties.
To study the thermal stability of the mentioned materials, compositions with different molar ratios of the precursors were
prepared. The influence of the solvent and water amounts on the gelation process was also investigated. The gels obtained
were characterised by IR spectrometry and their decomposition temperatures were determined by DTA/TG. Thermal stability of
the gels is rather influenced by their composition than the conditions of the gelation process.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
J. Somlai B. Kanyár R. Bodnár CS. Németh Z. Lendvai 《Journal of Radioanalytical and Nuclear Chemistry》1996,207(2):437-443
A significant dose contribution on the population could be derived from coal slags used as isolation material. Extremely high natural activities are measured in the coal slag, derived from the region of the settlement Ajka, Hungary. In some buildings monitored, the elevated -doses were nearly 5–10 times higher than the world average ones. The annual average indoor radon concentrations from the slag exceeded 400 Bq/m3 and in some cases up to 1200 Bq/m3. Due to the elevated exposure and the radon concentrations in the dwellings the annual dose was estimated to 8–24 mSv/y more than 5–10 times of the world average one. 相似文献
3.
M. Schnitzer C. Tarnocai P. Schuppli R. Hempfling R. Müller H.-R. Schulten 《Fresenius' Journal of Analytical Chemistry》1990,337(8):882-884
Summary The analytical potential of the combination of solid state NMR and soft ionization mass spectrometry for direct investigations of complex organic matter in soils without chemical pretreatment is demonstrated. The results show that the Oh horizon of a Gleysolic paleosol (±45 Ma) from the Canadian Arctic consists mainly of components of cuticular waxes which include 10-nonacosanol, C15–C36 n-fatty acids, C44–C75 n-alkyl monoesters and C60–C76 diesters. It is likely that these waxes originated from the coniferous and deciduous vegetation which dominated this area when these soils were formed and that the climate was warm and moist. 相似文献
4.
Gradient-index fiber-optic microprobes for minimally invasive in vivo low-coherence interferometry 总被引:1,自引:0,他引:1
We describe the design, construction, and application of what are believed to be the smallest fiber-optic probes used to date during imaging or diagnosis involving low-coherence interferometry (LCI). The probes use novel fiber-optic gradient-index (GRIN) lenses fabricated by a recently developed modified chemical-vapor-deposition (MCVD) process that avoids on-axis aberrations commonly marring MCVD-fabricated GRIN substrate. Fusing GRIN fiber lenses onto single-mode fiber yields automatically aligned all-fiber probes that insert into tissue through hypodermic needles as small as 31-gauge (inner diameter, 127 mum). We demonstrate the use of such probes with LCI by measuring microscopic brain motions in vivo. 相似文献
5.
Bramati A Hermier JP Khoury AZ Giacobino E Schnitzer P Michalzik R Ebeling KJ Poizat JP Grangier P 《Optics letters》1999,24(13):893-895
We studied anticorrelated quantum fluctuations between the TEM(00) and the TEM(01) transverse modes of a vertical-cavity surface-emitting semiconductor laser by measuring the transverse spatial distribution of the laser beam intensity noise. Our experimental results are found to be in good agreement with the predictions of a phenomenological model that accounts for quantum correlations between transverse modes in a light beam. 相似文献
6.
A. GARAY S. DEMETER K. KOVÁCS G. HORVÁTH ÁGNES FALUDI-DÁNIEL 《Photochemistry and photobiology》1972,16(2):139-144
Abstract— Circular dichroism (CD) spectra were studied in System I particles prepared by digitonin fragmentation of chloroplasts of normal maize and carotenoid-deficient mutants. CD bands of pigment molecules were found to be higher in particles than in solutions. This phenomenon was most pronounced for the particles containing the carotenoid composition of normal chloroplast lamellae. The CD signal of chlorophylls bound to particles of carotenoid-deficient chloroplasts was closer to that found in solutions. This indicates that aggregation and/or binding of chlorophylls in carotenoid-deficient mutants may be less extensive than in normal chloroplasts. 相似文献
7.
We introduce a compact two-photon fluorescence microendoscope based on a compound gradient refractive index endoscope probe, a DC micromotor for remote adjustment of the image plane, and a flexible photonic bandgap fiber for near distortion-free delivery of ultrashort excitation pulses. The imaging head has a mass of only 3.9 g and provides micrometer-scale resolution. We used portable two-photon microendoscopy to visualize hippocampal blood vessels in the brains of live mice. 相似文献
8.
Stokes-flow reversibility is violated in electrolyte solutions by a streaming-potential mechanism, where nonuniform convective currents within Debye layers surrounding charged particles induce electric fields in the electroneutral Ohmic bulk. We demonstrate the irreversibility consequences of this phenomenon for the problem of particle-pair sedimentation, where the two particles experience a repulsive force driven by bulk Maxwell stresses. At small separations the force scales inversely with the third power of separation distance. This singular behavior is associated with the counterrotation of the two torque-free particles, which leads through a lubrication mechanism to an intense electric field in the narrow gap between them. At large separations the force follows an inverse dependence upon the fourth power of separation, now associated with rectilinear particle motion. 相似文献
9.
10.