全文获取类型
收费全文 | 135篇 |
免费 | 8篇 |
专业分类
化学 | 68篇 |
力学 | 1篇 |
数学 | 40篇 |
物理学 | 34篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 13篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 1篇 |
1994年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1962年 | 4篇 |
1961年 | 3篇 |
1959年 | 1篇 |
排序方式: 共有143条查询结果,搜索用时 31 毫秒
41.
Mohammed Shahid Ali Syed Rafiuddin Mohsin Ghori Aamer Roshanali Khatri 《Chromatographia》2008,67(7-8):517-525
A simple and specific hydrophilic interaction liquid chromatography (HILIC) procedure for the quantification of metformin
hydrochloride (MFH) and its impurities in bulk pharmaceuticals and finished dosage forms has been developed. The method is
based on hydrophilic interaction of the analytes with silica. The influence of the weaker solvent, acetonitrile, pH and the
nature and ionic strength of the buffer was studied. Linearity range and percent recoveries for MFH were 100–400 μg mL−1 and 100.62%, respectively. Good validation data were obtained for all compounds. The method separates impurities cyanoguanidine
(CGD), melamine (MLN) and other degradation products with a run time of less than 13 min. Degradation studies involved thermal
stress, hydrolysis at various pHs and chemical and photolytic oxidation. 相似文献
42.
Om P. Khatri 《Applied Surface Science》2009,255(24):9817-9821
Vacuum ultraviolet (VUV, λ = 172 nm) patterning of alkyl monolayer on silicon surface has been demonstrated with emphasis on the diffusion of VUV induced oxygen-derived active species, which are accountable for the pattern broadening. The VUV photons photo-dissociates the atmospheric oxygen and water molecules into the oxygen-derived active species (oxidants). These oxidants photo-oxidize the hexadecyl (HD) monolayer in VUV irradiated regions (Khatri et al., Langmuir. 24 (2008) 12077), as well as the little concentration of oxidants diffuses towards the masked areas. In this study, we performed VUV patterning at a vacuum pressure of 10 Pa to track the diffusion pathways for the oxidants with help of gold nanoparticles (AuNPs; ? = 10 nm) immobilization. At VUV irradiated sites AuNPs are found as uniformly distributed, but adjacent to the pattern boundary we observed quasi-linear arrays of AuNPs, which are determined by diffusion pathways of the oxidants. The diffusion of oxidants plays vital role in pattern broadening. The site selective anchoring of AuNPs demonstrates the utility of VUV photons for the construction of functional materials with microstructural architecture. 相似文献
43.
Kantorovich gave an upper bound to the product of two quadratic forms, (X′AX) (X′A−1X), where X is an n-vector of unit length and A is a positive definite matrix. Bloomfield, Watson and Knott found the bound for the product of determinants |X′AX| |X′A−1X| where X is n × k matrix such that X′X = Ik. In this paper we determine the bounds for the traces and determinants of matrices of the type X′AYY′A−1X, X′B2X(X′BCX)−1 X′C2X(X′BCX)−1 where X and Y are n × k matrices such that X′X = Y′Y = Ik and A, B, C are given matrices satisfying some conditions. The results are applied to the least squares theory of estimation. 相似文献
44.
Bounds for several integrals (tail probabilities, for example) are established by showing that each integral is a Schur function. 相似文献
45.
46.
Electron-phonon scattering rates determined from the linewidths of acoustic open orbit resonances in copper have been analyzed by Monte-Carlo simulation, leading to numerical estimates of the average angle of scatter. The data suggest the dominance of transverse phonons as a scattering agent. 相似文献
47.
D.S. Khatri 《Physics letters. A》1976,57(3):285-286
Various studies have shown that the mean square amplitude of atoms on the surface of a crystal is almost twice that in the bulk. We believe that the results obtained by Kothari, using simple physical arguments for surface vibrations, were in error. We have also shown that the results could be explained by taking the contribution of bending waves in addition to surface vibrations for a 2-dimensional crystal. 相似文献
48.
Antiresonance (sharp attenuation minima) predicted theoretically by Sievert in 1967 and the rich harmonics observed experimentally by Khatri and Peverly in 1973 in copper have remained unexplained to a great extend. In this letter, we report our preliminary results on this novel effect (antiresonance) for shear waves propagated along the [111] crystallographic direction in silver. 相似文献
49.
50.