全文获取类型
收费全文 | 138篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 110篇 |
力学 | 4篇 |
数学 | 9篇 |
物理学 | 19篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1991年 | 1篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有142条查询结果,搜索用时 156 毫秒
21.
Soo Young Park Joong Hwan Yang Soon Hong Yuk Mu Shik Jhon 《Journal of Polymer Science.Polymer Physics》1999,37(13):1407-1411
Terpolymers composed of N‐n‐propylacrylamide (NPAAm), butyl methacrylate (BMA), and N,N‐diethylaminoethyl methacrylate (DEAEMA) were prepared in an attempt to investigate the temperature‐induced phase transition and its mechanism. Poly(NPAAm) showed the lower critical solution temperature (LCST) around 24°C in water. With the incorporation of DEAEMA with NPAAm, the LCST change was characterized by an initial increase. However, the LCST was shifted to the lower temperature at the later stage. This might be explained in terms of hydrophilic/hydrophobic contribution of DEAEMA to the LCST. The swelling behavior of copolymer gel in the various solvents and spin‐lattice relaxation time (T1) study by NMR strongly suggested the hydrophilic/hydrophobic contribution of DEAEMA to the LCST depending on the local environment. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1407–1411, 1999 相似文献
22.
A study of the spatial and temporal evolution of auto-ignition kernels using time-resolved tomographic OH-LIF 总被引:1,自引:0,他引:1
Jhon Pareja Ayane Johchi Tao Li Andreas Dreizler Benjamin Böhm 《Proceedings of the Combustion Institute》2019,37(2):1321-1328
In this paper, the spatial and temporal evolution of auto-ignition kernels from methane jets propagating into a NOx-vitiated, high-turbulence, hot air co-flow was studied by means of time-resolved tomographic laser-induced fluorescence of OH (Tomo OH-LIF). Measurements were performed using a burst dye laser system at 10 kHz for volumetric laser illumination and a multi-camera arrangement (8-views) for detection of the fluorescence signal. Auto-ignition kernels were detected three-dimensionally and tracked using a robust algorithm based on the intensity gradient of the volumetrically reconstructed signals. The size and location of the detected kernels were evaluated for operating conditions with different Reynolds numbers of the fuel jet. Results showed that auto-ignition randomly occurred with high probability in a well defined fairly axisymmetric radial region with strong fluctuations in the main direction of the flow. The increase of the Reynolds number of the fuel jet resulted in a radial spread of the location of auto-ignition events. The statistical evaluation of the orientation and growth of auto-ignition kernels with respect to the mean flow field showed that the kernels were oriented tangentially to the flow and temporally evolve towards this preferential direction as the ignition events progressed. 相似文献
23.
Junwon Han Byung Ho Jeon Chang Y. Ryu James J. Semler Young K. Jhon Jan Genzer 《Macromolecular rapid communications》2009,30(18):1543-1548
Interaction chromatography has been employed to validate that adsorption of poly[styrene‐co‐(4‐bromostyrene)] (PBrxS) random copolymers, where x denotes the mole fraction of 4‐bromostyrene (4–BrS) in PBrxS in solution depends on the average number of adsorptive segments, the type of adsorbing substrate, and on the co‐monomer sequence distribution in PBrxS.
24.
Jhon F. Perez Elizabeth Florez Cacier Z. Hadad Patricio Fuentealba Albeiro Restrepo 《ChemInform》2008,39(39):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
25.
For the first time to our knowledge, pulse-amplitude equalization of rational-harmonically mode-locked fiber ring laser pulses has been experimentally demonstrated using a polarization-maintaining laser resonator without any additional device. The pulse-amplitude distribution of the laser pulses was controlled by the modulator driving power, and stable pulse-amplitude-equalized pulses with repetition rates of 20, 30, and 40 GHz have been obtained in the linear region of the modulator. 相似文献
26.
SB Choi H Furukawa HJ Nam DY Jung YH Jhon A Walton D Book M O'Keeffe OM Yaghi J Kim 《Angewandte Chemie (International ed. in English)》2012,51(35):8791-8795
Caging cages: Crystals of a metal-organic framework, MOF-123 [Zn(7) O(2) (NBD)(5) (DMF)(2) ] have a three-dimensional porous structure in which DMF ligands (see picture, pink) protrude into small channels. Removal of these ligands triggers the transformation of this MOF to the doubly interpenetrating form, MOF-246 [Zn(7) O(2) (NBD)(5) ]. Moreover, addition of DMF into MOF-246 triggers reverse transformation to give MOF-123. NBD=2-nitrobenzene-1,4-dicarboxylate. 相似文献
27.
A custom designed vertical oscillation rheometer (VOR) is used for the rheological measurements of electrorheological (ER) fluids consisting of 15 and 20 vol.% semiconducting polyaniline particles suspended in silicone oil. The viscoelastic material functions, including complex viscosity and complex shear modulus, are measured via geometric parameters, measured force, and applied strain of the VOR. Viscoelastic properties of the ER fluids are also measured as a function of applied electric field strength and particle concentration. The VOR, equipped with a high voltage generator, can easily be constructed and used to measure ER properties. It is further found that polyaniline suspensions behave as viscoelastic materials in an electric field. In linear viscoelastic conditions, elasticity was promoted with the increment of electric field due to particle chain structure in the presence of the applied electric field. It is also found that the applied electric field rather than particle concentration enhanced the elasticity of ER fluids. 相似文献
28.
Young K. Jhon Rajendra R. Bhat Changwoo Jeong Orlando J. Rojas Igal Szleifer Jan Genzer 《Macromolecular rapid communications》2006,27(9):697-701
Summary: Quartz crystal microbalance with dissipation monitoring (QCM‐D) is employed to determine the effect of salt on the volume phase transition of thermoresponsive polymer brushes. Changes in mass and viscoelasticity of poly(N‐isopropylacrylamide) (PNIPAM) layers grafted from a QCM‐D crystal are measured as a function of temperature, upon contact with aqueous solutions of varying salt concentrations. The phase‐transition temperature of PNIPAM brushes, TC,graft, quantified from the QCM‐D measurements is found to decrease as the concentration of salt is increased. This phenomenon is explained by the tendency of salt ions to affect the structure of water molecules (Hofmeister effect). However, in contrast to the linear decrease in phase‐transition temperature upon increasing salt concentration observed for free PNIPAM, the trend in TC,graft for PNIPAM brushes is distinctively non‐linear.
29.
Seung J. Park Min S. Cho Sung T. Lim Hyoung J. Choi Myung S. Jhon 《Macromolecular rapid communications》2005,26(19):1563-1566
Summary: Multiwalled carbon nanotube (MWNT) nanocomposites dispersed in a poly(methyl methacrylate) (PMMA) matrix were prepared via suspension polymerization, in which radicals induced on the outer wall of the MWNTs by 2,2′‐azoisobutyronitrile initiate the grafting of PMMA. The synthesized MWNT/PMMA nanocomposite particles were found to have a spherical shape and exhibit a high electrical conductivity, mainly as a result of the carbon nanotubes. A suspension was prepared with MWNT/PMMA particles in insulating silicone oil and its electrorheological properties were investigated by controlling applied direct current (DC) electric field strengths.
30.
The spreading mechanism of nonpolar perfluoropolyether films on carbon surfaces is examined in the mesoscopic regime, including both submonolayer and multilayer films. For the submonolayer film, adsorption-desorption is a main mechanism for spreading, and the surface diffusion coefficients increase as the film thickness increases. The driving force for the spreading in the submonolayer regime is the gradient of the disjoining pressure, which is described by the two-dimensional virial equation. For the multilayer film regime, the spreading characteristics are determined by the molecular weight and the disjoining pressure gradient, which is assumed to be purely van der Waals in nature. We adopt a partial slip boundary condition to analyze the multilayer film, which qualitatively explains the dependence of the surface diffusion coefficient on film thickness. Copyright 2000 Academic Press. 相似文献