全文获取类型
收费全文 | 155篇 |
免费 | 3篇 |
专业分类
化学 | 82篇 |
晶体学 | 6篇 |
力学 | 5篇 |
数学 | 22篇 |
物理学 | 43篇 |
出版年
2021年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有158条查询结果,搜索用时 0 毫秒
91.
K. Muthukkumaran P. Kuppusami R. Kesavamoorthy T. Mathews E. Mohandas V. S. Raghunathan S. Selladurai 《Ionics》2008,14(2):165-171
Ceria rare earth solid solutions are known as solid electrolyte with potential application in oxygen sensors and solid oxide
fuel cells. We report the preparation of gadolinia-doped ceria, Ce0.90Gd0.10O1.95, by the conventional solid-state reaction method and the preparation of thin films from a sintered pellet of gadolinia-doped
ceria by the pulsed laser deposition technique. The effect of process conditions, such as substrate temperature, oxygen partial
pressure, and laser energy on microstructural properties of these films are examined using powder X-ray diffraction, scanning
electron microscopy, atomic force microscopy, and Raman spectroscopy. 相似文献
92.
93.
Experimental investigations on the effect of Strouhal number and rotor solidity on the performance of 0.2m diameter Wells self rectifying air turbine with NACA 0021 profile blades are presented. The results show an increase in starting torque with the Strouhal number of airflow and rotor solidity. The effect of Strouhal number on the running performance of the turbine is solidity dependent 相似文献
94.
We develop the theory of electrohydrodynamic instability in nematic liquid crystals by incorporating the flexoelectric terms.
Using a one-dimensional linear analysis of the problem for an applied DC field, we demonstrate that for the usual materials
the rolls have an oblique orientation as has been found experimentally. We also provide an experimental evidence for the strong
flexoelectric influence on the director profile in the rolls. 相似文献
95.
96.
Harroun TA Koslowsky M Nieh MP Raghunathan VA Katsaras J 《The European physical journal. E, Soft matter》2004,13(4):359-362
Finite-size effects in stacks of phospholipid bilayers, in the fluid
phase, are investigated using samples oriented on silicon substrates. Recently in this journal, such effects have been suggested as the probable cause of reduced lamellar repeat spacings in very thin samples made up of a few (<10) bilayers. Our systematic studies on samples of different thicknesses do not support this conclusion. At full hydration all samples are found to have the same repeat spacing, irrespective of their thickness. At lower hydrations, on the other hand, very thin samples, consisting of only a few bilayers, have a slightly larger spacing.Received: 20 January 2004, Published online: 20 April 2004PACS:
68.08.Bc Wetting - 87.15.Ya Fluctuations - 87.16.Dg Membranes, bilayers, and vesicles - 87.64.Bx Electron, neutron, and X-ray diffraction and scattering 相似文献
97.
Wang MF Raghunathan N Ziaie B 《Langmuir : the ACS journal of surfaces and colloids》2007,23(5):2300-2303
Superhydrophobic surfaces are biomimetic structures with potential applications in several key technological areas. In the past decade, several top-down and bottom-up fabrication methods have been developed to create such surfaces. These typically combine a hierarchical structure and low surface energy coatings to increase the contact angle and decrease the rolling angles. Silicon-based superhydrophobic surfaces are particularly attractive since they can be integrated with active electronics in order to protect them from the detrimental effects of environmental water and moisture. In this work, we introduce a simple and inexpensive process incorporating electrochemical surface modification (to create a fractal shape micro-nano topography) in combination with a final wet etching step to fabricate a superhydrophobic silicon surface with a contact angle of 160 degrees and a sliding angle of less than 1 degree. 相似文献
98.
Ghosh SK Ganapathy R Krishnaswamy R Bellare J Raghunathan VA Sood AK 《Langmuir : the ACS journal of surfaces and colloids》2007,23(7):3606-3614
We report the observation of an intermediate mesh phase with rhombohedral symmetry, corresponding to the space group Rm, in a mixed surfactant system formed by the cationic surfactant cetyltrimethylammonium bromide (CTAB) and the organic salt 3-sodium-2-hydroxy naphthoate (SHN). It occurs between a random mesh phase (L(alpha)(D)) and a lamellar phase (L(alpha)) at low temperatures; at higher temperatures, the (L(alpha)(D)) phase transforms continuously into the (L(alpha)) phase with an increasing surfactant concentration (phi(s)). To separate the effects of salt and phi(s) on the phase behavior, the ternary system consisting of cetyltrimethylammonium 3-hydroxy-naphthalene-2-carboxylate (CTAHN), sodium bromide (NaBr), and water was studied. The intermediate mesh phase is found in this system at high NaBr concentrations. The micellar aggregates, both in the intermediate and random mesh phases, are found to be made up of a two-dimensional network of rod-like segments, with three rods meeting at each node. The average mesh size increases with phi(s), and the transition from the random mesh phase to the intermediate phase is found to occur when it is approximately 1.5 times the lamellar periodicity. The intermediate mesh phase is absent in the equimolar dodecyltrimethylammonium bromide (DTAB)-SHN system, indicating the role of the surfactant chain length in the formation of this phase. This system exhibits a random mesh phase over a very wide range of water content, with the average mesh size decreasing upon an increasing phi(s), contrary to the trend seen in the CTAB-SHN system. 相似文献
99.
Muthian Shanmugasundaram Raghavachary Raghunathan Ezekiel J. Padma Malar 《Heteroatom Chemistry》1998,9(5):517-522
Synthesis of a series of novel 1,3,2′-triphenyl-4-aryl spiropyrazolines [5.4′]-2′-butenolides has been accomplished in good yield by regioselective 1,3-dipolar cycloaddition of diphenylnitrilimine with (E)-3-arylidenebutenolides. X-ray crystal structure analysis of one of the products 4a confirms the structure of the product and the regiochemistry of cycloaddition. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:517–522, 1998 相似文献
100.
Mu-Ping Nieh V.A. Raghunathan Charles J. Glinka Thad Harroun John Katsaras 《Macromolecular Symposia》2005,219(1):135-146
The structures of bicelle mixtures composed of dimyristoyl and dihexanoyl phosphatidylcholines (DMPC and DHPC) with DMPC/DHPC molar ratios of 3.2 and 5 are characterized using polarized optical microscopy (POM) and small angle neutron scattering (SANS). Three phases, isotropic (I), chiral nematic (N*) and smectic (S) are observed as temperature (T) varies from 10 to 70 °C. The structure of the magnetically alignable N* phase, which was previously considered to be made up of discoidal micelles, is found to be composed of “ribbons”. Doping with the charged lipid, dimyristoyl phosphatidylglycerol (DMPG), which has the same 14:0 hydrocarbon chains as DMPC, results in a structural change of the aggregates where only the isotropic and smectic phases are observed. The smectic phase for the mixtures doped with DMPG is shear-alignable and follows one-dimensional swelling. However, at high-T zwitterionic DMPC/DHPC mixtures form multi-lamellar vesicles (MLV) with a relatively constant lamellar spacing of 66 Å, independent of water content. 相似文献