全文获取类型
收费全文 | 90篇 |
免费 | 2篇 |
专业分类
化学 | 33篇 |
力学 | 2篇 |
数学 | 6篇 |
物理学 | 51篇 |
出版年
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2013年 | 6篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
Calcium ion is determined in the internal phase of oil-based drilling fluids with a calcium ion-selective electrode after treatment with a 1:1 (v/v) xylene/isopropanol mixture and 4 M potassium chloride. Results obtained by this potentiometric method and by the Magcobar titration on laboratory-prepared muds and on a North Sea field mud (Statfjord) were in satisfactory agreement. 相似文献
2.
3.
4.
5.
Arthur L. Ruoff 《高压研究》2013,33(5-6):639-645
Abstract We have now taken two materials (W, Mo) to pressures greater than the pressure at the center of the earth for the first time, with all pressures based on x-ray diffraction and shock-based equations of state. The present paper describes x-ray diffraction studies of a sample in which pressure equals or exceeds 438 GPa. It is noted that as a result of the process of pressure strengthening, pressures of 1 TPa may be attainable. Presented at the IUCr Workshop on ‘Synchrotron Radiation Instrumenration for HighPressure Crystallography’. Daresbury Laboratory 20-21 July 1991 相似文献
6.
7.
N. H. Tea R. -C. Yu M. B. Salamon D. C. Lorents R. Malhotra R. S. Ruoff 《Applied Physics A: Materials Science & Processing》1993,56(3):219-225
We have performed thermal conductivity measurements on C60 and C70 crystals grown by sublimation. For single crystal C60, the thermal conductivity k is 0.4 W/m K at room temperature and is nearly temperature independent down to 260K. We observed a sharp orientational phase transition at 260K, indicated by a 25% jump in k. Below 90K, k is time dependent, which manifests itself as a shoulder-like structure at 85K. The temperature and time dependence of k below 260K can be described by a simple model which accounts for the thermally activated hopping of C60 molecules between two nearly degenerate orientations, separated by an energy barrier of 240 meV. It is found that solvents have a strong influence on the physical properties of C70 crystals. For solvent-free C70 crystal, k is about constant above 300K. There is a broad first-order phase transition in k at 300K with a 25% jump. We associate this transition with the aligning of the fivefold axes of the C70 molecules along the c-axis of the hexagonal lattice. Upon further cooling, k increases and is time independent. 相似文献
8.
W. Krakow N. M. Rivera R. A. Roy R. S. Ruoff J. J. Cuomo 《Applied Physics A: Materials Science & Processing》1993,56(3):185-192
Thin films (25-2500 Å) of C60 molecules have been deposited on both (001) NaCl and mica substrates at varying temperatures by resistive evaporation. Both electron diffraction and high resolution microscopy have been used to assess the degree of crystallinity, the orientational ordering and the nature of the defects present in these face-centered-cubic films. For NaCl, optimum conditions yielded polycrystalline films with a tendency towards a 110 orientation, while for mica, extended single crystal films have been fabricated which exhibit a 111 direction normal to the film surface. 相似文献
9.
W. Ding L. Calabri K. M. Kohlhaas X. Chen D. A. Dikin R. S. Ruoff 《Experimental Mechanics》2007,47(1):25-36
The fracture strengths and elastic moduli of arc-grown multi-walled carbon nanotubes (MWCNTs) were measured by tensile loading
inside of a scanning electron microscope (SEM). Eighteen tensile tests were performed on 14 MWCNTs with three of them being
tested multiple times (3×, 2×, and 2×, respectively). All the MWCNTs fractured in the “sword-in-sheath” mode. The diameters
of the MWCNTs were measured in a transmission electron microscope (TEM), and the outer diameter with an assumed 0.34 nm shell
thickness was used to convert measured load-displacement data to stress and strain values. An unusual yielding before fracture
was observed in two tensile loading experiments. The 18 outer shell fracture strength values ranged from 10 to 66 GPa, and
the 18 Young's modulus values, obtained from a linear fit of the stress–strain data, ranged from 620 to 1,200 GPa, with a
mean of 940 GPa. The possible influence of stress concentration at the clamps is discussed. 相似文献
10.
Abstract Review of phase transitions and equations of state at multimegabar pressures (100–300 GPa) is presented. Energy dispersive x-ray diffraction techniques in conjunction with synchrotron radiation sources are used. Besides several transition metals, Pt to 282 GPa, Re to 251 GPa, W to 209 GPa, and Fe to 255 GPa, the special focus is on Group IVA elements and isoelectronic III-V compounds. At high pressure, the isoelectronic materials are isostructural and exhibit similar equation of state. 相似文献