全文获取类型
收费全文 | 120篇 |
免费 | 0篇 |
专业分类
化学 | 95篇 |
晶体学 | 1篇 |
数学 | 3篇 |
物理学 | 21篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有120条查询结果,搜索用时 24 毫秒
41.
Hiroyuki Sasabe Cornelius T. Moynihan 《Journal of Polymer Science.Polymer Physics》1978,16(8):1447-1457
Structural relaxation in poly(vinyl acetate) (PVAc) in and slightly above the glass-transition region has been studied by monitoring the time dependence of enthalpy using differential scanning calorimetry and the frequency dependence of electric polarization by dielectric loss measurements. The results have been analyzed to yield the kinetic parameters characterizing the structural relaxation and are compared with similar analyses of previously published shear compliance and volume relaxation experiments. Relaxation of enthalpy, electric polarization, volume, and shear stress in PVAc all appear to be characterized by somewhat different relaxation times. The difference between the volume and enthalpy relaxation times, coupled with the fact that PVAc exhibits a Prigogine–Defay ratio greater than unity, is evidence for a previously proposed connection between the thermodynamics and kinetics of structural relaxation in terms of an order parameter model. 相似文献
42.
H. S. Zhou I. Honma Joseph W. Haus H. Sasabe H. Komiyama 《Journal of luminescence》1996,70(1-6):21-34
The synthesis of coated nanoparticles is a new direction in engineering, specifically in the study of physical properties of materials. We examine semiconductor coated semiconductor particles, CdS/PbS, and metal coated particles, Au2S/Au, and the theoretical basis for their unique properties. Coated self-assembled nanoparticles are also studied and recent progress is reported. 相似文献
43.
We investigate Wess-Zumino terms in higher-dimensional nonlinear sigma models using the higher-dimensional hedgehog ansatz proposed by us. The gauged Wess-Zumino terms are also calculated from a fermion determinant, and we comment on extended objects or a dibaryon ansatz.Partially supported by the Grant-in-Aid for Scientific Research, No. 61460005. 相似文献
44.
[structure: see text] Sphingomyelin nitrogen analogue 1 was designed and synthesized as a sphingomyelinase inhibitor. The synthesis was established by continuous Hofmann rearrangement and Crutius rearrangement as key steps in constructing the 3-hydroxy-1,2-diamine structure in the backbone of 1. This analogue showed moderate inhibitory activity toward SMase isolated from B. cereus. 相似文献
45.
Takahashi M Nagashima M Shigeoka S Kamimura H Kamata K 《Journal of chromatography. A》2002,953(1-2):299-303
Fast ion-exchange chromatography has been developed and applied to the separation of common inorganic anions. Using a didodecyldimethylammonium bromide (DDAB) coated short (30 mm x 4.6 mm) ODS analytical column (3-microm particle size) and a 5 mM phthalate eluent (pH 7.5) the isocratic separation of nine common anions in 160 s was possible, with the first seven anions, including phosphate, chloride and sulphate, separated within 65 s. Detection was achieved using indirect UV at 279 nm. The high capacity, highly hydrophobic ion-exchange coating demonstrated excellent stability over time, even at elevated temperatures (45 degrees C) and exhibited unusual selectivity for common anions (retention order=fluoride, carbonate, phosphate, chloride, bromate, nitrite, sulphate, bromide and nitrate). The developed chromatography was successfully applied to the rapid analysis of river water and seawater samples. 相似文献
46.
Hakogi T Monden Y Taichi M Iwama S Fujii S Ikeda K Katsumura S 《The Journal of organic chemistry》2002,67(14):4839-4846
The highly efficient and stereocontrolled syntheses of sphingomyelin carbon analogues 1 and 2 were achieved by effectively utilizing Hofmann rearrangement of enantiomerically pure beta-hydroxyamide 7, which was prepared by an asymmetric hydrogenation of alpha-acyl-gamma-butyrolactone 9 and ring opening with NH(3). Intermediary isocyanate 6 was selectively trapped with the vicinal hydroxy group in an intramolecular fashion to produce an oxazolidinone derivative, 5. In the synthesis of a quite polar compound such as 1, a convenient one-pot procedure of the introduction of a benzyloxycarbonyl group into the hydroxy group resulting from the oxazolidinone ring opening is another key point, because, in addition to the efficiency, this protecting group was easily removable by a simple procedure and workup at the final step. Both synthesized compounds 1 and 2 showed moderate inhibitory activity toward sphingomyelinase from B. cereus. 相似文献
47.
Hassan Badawi Primo
Loren
ak Kurt W. Hillig II Misako Imachi Robert L. Kuczkowski 《Journal of Molecular Structure》1987,162(3-4):247-254
The microwave spectrum of the normal species of the gauche, gauche isomer of allyl alcohol has been reassigned and rotational and centrifugal distortion constants have been determined. Rotational constants of nine deuterated species three carbon-13 species and the oxygen-18 species have also been obtained. These data were used to estimate structural parameters by least-squares fitting of the effective moments of inertia. Good agreement with an earlier electron diffraction and ab initio study was obtained. Unassigned transitions from another isomer were observed, presumably the cis, gauche conformer. 相似文献
48.
Oil soluble surface active substances,(HFPO)n-Ar, where Ar is an aryl group and (HFPO)n is an oligo(hexafluoropropene oxide) group, n = 2 ? 5, were prepared and tested for their surface activities in toluene or -xylene. Addition of a small amount of (HFPO)4–6-Ar (0.2–0.5 wt%) was found to decrease remarkably the surface tension of these solvents (down to 12–14 dyn·cm?1 at 20 °C). Water soluble surfactants (HFPO)n-Ar′SO3Na, where Ar′ is an arylene group, were also prepared by sulfonation of (HFPO)n-Ar. Some of these substances (n = 4 ? 6) decreased the surface tension of water down to 16 dyn·cm?1 at 20 °C in the concentration of 1O?4–1O?5 mole·1?1. 相似文献
49.
Hisahiro Sasabe G. Abraham Rajkumar Nobuhiro Kihara Kazuhiko Mizuno Toshikazu Takata 《Tetrahedron》2006,62(9):1988-1997
Synthesis of [60]fullerene (C60)-functionalized rotaxanes via Diels-Alder reactions with C60 is described. Diels-Alder reaction of C60 and sulfolene moiety as masked diene attached on the wheels of rotaxanes results in high yields of C60 incorporation. Rotaxanes are prepared by tin-catalyzed urethane-forming end-capping reaction with isocyanate of pseudorotaxane having the wheel carrying C60 functionality as introduced by the Diels-Alder reaction. The Diels-Alder reaction was accomplished as end-capping reaction between C60 and pseudorotaxane bearing sultine moiety as masked diene on the axle terminal. A variety of C60-containing [2]rotaxanes was prepared in moderate to good yields by these Diels-Alder protocols. 相似文献
50.
The analysis of the orbital interaction between an alkali metal ion and the surrounding solvent molecules is performed for aqueous solutions of Li+, Na+, and K+, by means of the ab initio MO method with the aid of the quantum mechanical (QM)/molecular mechanics (MM) method. A total of 171 water molecules are included for each system. The effect of Li+ orbitals reaches as far as 6 Å 7 Å for Na+; and 9 Å for K+. This effect is caused by the orbital interactions between the valence orbitals of an alkali metal ion and of the surrounding water molecules. The electrostatic interaction and the orbital interaction must not be neglected. The difference in the effect between the alkali metal ions originates from the difference in the valence orbital extensions of the alkali metal ions. 相似文献