全文获取类型
收费全文 | 124篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
化学 | 80篇 |
晶体学 | 2篇 |
力学 | 4篇 |
数学 | 5篇 |
物理学 | 36篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 2篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1928年 | 1篇 |
1923年 | 1篇 |
1915年 | 3篇 |
1902年 | 1篇 |
1893年 | 2篇 |
排序方式: 共有127条查询结果,搜索用时 12 毫秒
81.
M. Musso F. Aliotta C. Vasi R. Aschauer A. Asenbaum Emmerich Wilhelm 《Journal of Molecular Liquids》2004,110(1-3):33-41
The frequency dependence of hypersonic absorption and the dispersion of hypersonic speed in liquid sulfur dioxide (SO2) were determined at (293.75±0.30) K and at (284.65±0.30) K by Brillouin spectroscopy. The results are used to experimentally establish the second relaxation step in the double vibrational relaxation of these quantities in the liquid phase, which was first conjectured by R. Bass and J. Lamb, Proc. R. Soc. Ser. A (1958) 243, 94. This second relaxation takes place at approximately 1.5 GHz for both temperatures within experimental error, whereas the first relaxation step, previously determined by ultrasonic spectroscopy, takes place at approximately 23 MHz. In the course of this investigation, some evidence was found that for the temperatures considered the shear viscosity relaxes in the hypersonic frequency range. 相似文献
82.
83.
Emerich Selch 《Monatshefte für Chemie / Chemical Monthly》1893,14(1):1-7
Ohne Zusammenfassung 相似文献
84.
85.
We present a mean field theory for melts and solutions of reversibly crosslinked polymers. In our model, crosslinks are considered as local bonds between two monomers. For a blend of A+B+AB polymers, we assume reversible crosslinks between the copolymers AB with a crosslink strength z and interaction weights ω(A) and ω(B) for monomers of type A and B, respectively. The usual mean field model for polymer blends without reversible crosslinks is recovered if z vanishes. With or without crosslinks, the A+B+AB blend can form a lamellar phase with A and B rich regions. If reversible crosslinks are enabled and ω(A) differs strongly from ω(B), the lamellar nanophase separation of A and B monomers is accompanied by a similar segregation of crosslinked and noncrosslinked polymers. If ω(A) and ω(B) are equal, crosslinked copolymers are well mixed with the homopolymers. For a homopolymer solution with reversible crosslinks between the polymers, our calculations show that polymers and solvent molecules are separated macroscopically if the Flory-Huggins interaction parameter and the crosslink strength are suitably high or if the volume fraction of polymers or the chain length are suitably low. 相似文献
86.
Here, we review the basic concepts and applications of the phase-field-crystal (PFC) method, which is one of the latest simulation methodologies in materials science for problems, where atomic- and microscales are tightly coupled. The PFC method operates on atomic length and diffusive time scales, and thus constitutes a computationally efficient alternative to molecular simulation methods. Its intense development in materials science started fairly recently following the work by Elder et al. [Phys. Rev. Lett. 88 (2002), p. 245701]. Since these initial studies, dynamical density functional theory and thermodynamic concepts have been linked to the PFC approach to serve as further theoretical fundamentals for the latter. In this review, we summarize these methodological development steps as well as the most important applications of the PFC method with a special focus on the interaction of development steps taken in hard and soft matter physics, respectively. Doing so, we hope to present today's state of the art in PFC modelling as well as the potential, which might still arise from this method in physics and materials science in the nearby future. 相似文献
87.
Protons from nuclear reactions induced by 14 MeV neutrons are studied by means of a telescope, consisting of three CO2-flow counters and a surface barrier detector. The resolving power of this arrangement, tested with recoil protons is found to be 400 keV at 14 MeV, the efficiency (counts per incident neutron) being 3 · 10?7. From the measured energy spectra of the protons from the metals Ti, Fe, Ni and Zn in forward direction statistical theory parameters are evaluated. In the level density expression ρ(Ea)~E a ?n exp(2√aEa) the exponentn=2, including angular momentum effects is found to be in better agreement with the experimental data than othern-values frequently used. 相似文献
88.
89.
M. Maciejewski E. Ingier-Stocka W.-D. Emmerich A. Baiker 《Journal of Thermal Analysis and Calorimetry》2000,60(3):735-758
The complexity of the processes occurring during cobalt oxalate dihydrate (COD) decomposition indicates that an interpretation
of the mechanism based only on the TG curve is of little value. Mass change alone does not allow deeper insight into all of
the potential primary and secondary reactions that could occur. The observed mass changes (TG) and thermal effects (DTA/DSC)
are a superposition of several phenomena and thus do not necessarily reflect COD decomposition alone. Investigation of the
mechanism of decomposition requires the application of different simultaneous techniques that allow the qualitative and quantitative
determination of the composition of the gaseous products.
Composition of the solid and gaseous products of COD decomposition and heats of dehydration and oxalate decomposition were
determined for inert, oxidizing and hydrogen-containing atmospheres. Contrary to previous suggestions about the mechanism
of cobalt oxalate decomposition, the solid product formed during decomposition in helium contains not only metallic Comet, but also a substantial amount of CoO (ca 13 mol%). In all atmospheres, the composition of the primary solid and gaseous
products changes as a result of secondary gas-solid and gas-gas reactions, catalyzed by freshly formed Comet.
The course of the following reactions has been investigated under steady-state and transient conditions characteristic for
COD decomposition: water gas shift, Fischer-Tropsch, CO disproportionation, CoO reduction by CO and H2, Comet oxidation under rich and lean oxygen conditions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
90.
The solubility of nitrogen in pure liquid water was measured in the pressure range 45 to 115 kPa and in the temperature range 5 to 50°C. These data are used to obtain Henry coefficients H
2,1
(T,P
s,1
) at the vapor pressure P
s,1
of water. The temperature dependence of H
2,1
(T,P
s,1
) is accounted for by both a Clarke-Glew (CG) type fitting equation, and a power series in T–1, as suggested by Benson and Krause (BK). The imprecision of our measurements is characterized by an average deviation of ±0.038% from a four-term CG equation, and by an average deviation of ±0.042% from a three-term BK equation. From the temperature variation of H
2,1
(T,P
s,1
) partial molar quantities referring to the solution process, such as enthalpies and heat capacities of solution, are obtained. They are given in tabular form, together with H
2,1
(T,P
s,1
) and derived Ostwald coefficients L, at rounded temperatures. Finally, experimental results are compared with values calculated via scaled particle theory. 相似文献