全文获取类型
收费全文 | 94篇 |
免费 | 3篇 |
专业分类
化学 | 69篇 |
晶体学 | 3篇 |
数学 | 18篇 |
物理学 | 7篇 |
出版年
2019年 | 2篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 4篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 2篇 |
1966年 | 4篇 |
1964年 | 1篇 |
1963年 | 3篇 |
排序方式: 共有97条查询结果,搜索用时 218 毫秒
91.
Shizuo Miyajima 《Semigroup Forum》1992,45(1):226-240
Communicated by R. Nagel 相似文献
92.
93.
Yoshida H Narisawa S Fujita S Ruixia L Arai M 《Physical chemistry chemical physics : PCCP》2012,14(14):4724-4733
The formation and adsorption of CO from CO(2) and H(2) at high pressures were studied over alumina-supported noble metal catalysts (Pt, Pd, Rh, Ru) by in situ FTIR measurements. To examine the effects of surface structure of supported metal particles and water vapor on the CO adsorption, FTIR spectra were collected at 323 K with untreated and heat (673 K) treated catalysts in the absence and presence of water (H(2)O, D(2)O). It was observed that the adsorption of CO occurred on all the metal catalysts at high pressures, some CO species still remained adsorbed under ambient conditions after the high pressure FTIR measurements, and the frequencies of the adsorbed CO species were lower either for the heat treated samples or in the presence of water vapor. It is assumed that the CO absorption bands on atomically smoother surfaces appear at lower frequencies and that water molecules are adsorbed more preferentially on atomically rough surfaces rather than CO species. 相似文献
94.
Shigeo Yamaguchi Hitoshi Kurusu Yoichi Kawakami Shizuo Fujita Shigeo Fujita 《Superlattices and Microstructures》1998,23(6):1189-1195
Photo-pumped lasing properties have been investigated in a CdSe/ZnSe/ZnSSE single quantum wells (SQWs) with the well-layer thickness (LW) of 1, 2 and 3 monolayer (ML). At 20 K, the laser threshold for the SQW withLW = 1 ML was the lowest in spite of the smallest active layer thickness. The carrier (exciton) sheet density at the threshold (n)thwas estimated to be as low as 7 × 1010cm−2, which is well below Mott's screening density. Time-resolved photoluminescence has revealed that the localized biexciton band, whose peak energy agrees with the lasing peak, appeared on the low-energy side of the main PL peak at this level of carrier concentrations. Theoretical calculation has also shown that the localized biexciton recombination has to be taken into account for the lasing process. On the contrary, thenthvalues of the SQWs with 2 and 3 ML are 1 order of magnitude larger than that of the SQW with 1 ML. This may be due to the smaller oscillator strength of both localized excitons and localized biexcitons because of the larger inhomogeneous broadening, resulting in an increased carrier density for achieving optical gain sufficient to overcome the reflection losses. 相似文献
95.
Crazing and/or shear yielding mechanisms in multiphase polymer alloys play a critical role in toughening. The present paper describes the use of finite element models (FEM) to simulate the crazing and shear deformation behaviour around the particles embedded in brittle or ductile matrices. The FEM simulation results on the stress distribution reveal that the dilatational stress within the rubber particles is high enough to cavitate. The stability of craze growth can be reached when the compliant particle is incorporated in a brittle matrix. On the other hand, shear yielding around the particle occurs in the equator of the particle/matrix interface when the stress locally exceeds the yield stress of the matrix. This yield-initiation stress increases with the increase in the elastic modulus and Poisson's ratio of the particles. The toughening mechanism, that cavitation occurs first followed by shear yielding to form a neck between the particles, is discussed based on the simulation results for the two-particle model. 相似文献
96.
Ikuo Narisawa Takashi Kuriyama Bernd Schemer Klaus Friedrich 《Macromolecular Symposia》1996,101(1):273-280
Ductile polymers are significantly toughened by the addition of an elastomeric phase. The rubber phase acts as a stress concentrator, cavitates during the loading process and initiates localized plastic deformation in matrix. This paper deals with the simulation of the deformation behavior of rubber toughened polycarbonate and the fracture process of the embedded rubber particle. A two-dimensional one particle- and two-particle model with varying surface-to-surface interparticle distances are established. The calculation showed that the polymer matrix has plastically deformed before cavitation for the one-particle model whereas cavitation occurs in the elastic state of the matrix for the two-particle model. Cavitation itself is proved to be a change from the particle-system towards a void-system for both cases. The toughness of the post-cavitated void-system is shown to be dependent on the surface-to-surface interparticle distance and the strain-hardening characteristic of the matrix polymer. 相似文献
97.