全文获取类型
收费全文 | 143篇 |
免费 | 6篇 |
专业分类
化学 | 89篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 18篇 |
物理学 | 38篇 |
出版年
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 11篇 |
2012年 | 15篇 |
2011年 | 7篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有149条查询结果,搜索用时 29 毫秒
81.
S.W. D′Souza J. Nayak M. Maniraj Abhishek Rai R.S. Dhaka S.R. Barman D.L. Schlagel T.A. Lograsso Aparna Chakrabarti 《Surface science》2012,606(3-4):130-136
Ni2MnGa(100) single crystal studied using low energy electron diffraction (LEED) and ultraviolet photoemission spectroscopy (UPS) exhibits interesting modification of the surface properties that are mainly influenced by surface composition as well as intrinsic effects. In the martensite phase, the LEED spot profiles show presence of an incommensurate modulation for the stoichiometric surface. In contrast, a commensurate modulation is observed for Mn-excess Ni–Mn–Ga surface. A pre-martensite phase is identified at the surface. Both the surface martensitic and pre-martensitic transition temperatures decrease as the Mn content increases. The UPS spectra in the austenite phase exhibit systematic change in shape as a function of surface composition that can be related to changes in the hybridization between Ni and Mn 3d states. The spectra in the martensite phase exhibit interesting modifications near the Fermi level, which has been compared to density of states calculated for a modulated structure by ab-initio density functional theory. Intrinsic surface properties dissimilar from the bulk are enhanced hysteresis width of the martensite transition and increased pre-martensitic transition temperature. 相似文献
82.
83.
84.
From the first principles calculation based on the density functional theory, we find that consideration of electron–electron correlation drives Fe2CrSn from a barely half-metallic state to a magnetic semiconductor. However, in both cases, the magnetic state remains ferrimagnetic with a total spin moment of 2μB, with Cr carrying a large local moment that is oppositely aligned to that of Fe. 相似文献
85.
Dingari NC Barman I Singh GP Kang JW Dasari RR Feld MS 《Analytical and bioanalytical chemistry》2011,400(9):2871-2880
Although several in vivo blood glucose measurement studies have been performed by different research groups using near-infrared
(NIR) absorption and Raman spectroscopic techniques, prospective prediction has proven to be a challenging problem. An important
issue in this case is the demonstration of causality of glucose concentration to the spectral information, especially as the
intrinsic glucose signal is smaller compared with that of the other analytes in the blood–tissue matrix. Furthermore, time-dependent
physiological processes make the relation between glucose concentration and spectral data more complex. In this article, chance
correlations in Raman spectroscopy-based calibration model for glucose measurements are investigated for both in vitro (physical
tissue models) and in vivo (animal model and human subject) cases. Different spurious glucose concentration profiles are assigned
to the Raman spectra acquired from physical tissue models, where the glucose concentration is intentionally held constant.
Analogous concentration profiles, in addition to the true concentration profile, are also assigned to the datasets acquired
from an animal model during a glucose clamping study as well as a human subject during an oral glucose tolerance test. We
demonstrate that the spurious concentration profile-based calibration models are unable to provide prospective predictions,
in contrast to those based on actual concentration profiles, especially for the physical tissue models. We also show that
chance correlations incorporated by the calibration models are significantly less in Raman as compared to NIR absorption spectroscopy,
even for the in vivo studies. Finally, our results suggest that the incorporation of chance correlations for in vivo cases
can be largely attributed to the uncontrolled physiological sources of variations. Such uncontrolled physiological variations
could either be intrinsic to the subject or stem from changes in the measurement conditions. 相似文献
86.
Gopa Barman 《Tetrahedron letters》2010,51(2):297-300
A simple methodology for the conversion of substituted N-aryl-γ-lactam 2/3-carboxylic acids to substituted N-aryl-diformylated pyrroles has been developed. Several γ-lactam 2/3-carboxylic acids were subjected to Vilsmeier reagent and substituted diformylated pyrroles are isolated in one-step process. 相似文献
87.
Light Harvesting and White‐Light Generation in a Composite of Carbon Dots and Dye‐Encapsulated BSA‐Protein‐Capped Gold Nanoclusters 下载免费PDF全文
Monoj Kumar Barman Bipattaran Paramanik Dipankar Bain Prof. Amitava Patra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11699-11705
Several strategies have been adopted to design an artificial light‐harvesting system in which light energy is captured by peripheral chromophores and it is subsequently transferred to the core via energy transfer. A composite of carbon dots and dye‐encapsulated BSA‐protein‐capped gold nanoclusters (AuNCs) has been developed for efficient light harvesting and white light generation. Carbon dots (C‐dots) act as donor and AuNCs capped with BSA protein act as acceptor. Analysis reveals that energy transfer increases from 63 % to 83 % in presence of coumarin dye (C153), which enhances the cascade energy transfer from carbon dots to AuNCs. Bright white light emission with a quantum yield of 19 % under the 375 nm excitation wavelength is achieved by changing the ratio of components. Interesting findings reveal that the efficient energy transfer in carbon‐dot–metal‐cluster nanocomposites may open up new possibilities in designing artificial light harvesting systems for future applications. 相似文献
88.
89.
Anup Kumar P. B. Barman Raman Sharma 《Journal of Thermal Analysis and Calorimetry》2013,114(3):1003-1013
Effect of Ag doping on the crystallization kinetics of amorphous Se80.5Bi1.5Te18?yAgy (for y = 0, 1.0, 1.5, and 2.0 at.%) glassy alloys has been studied by differential scanning calorimetry (DSC). The DSC curves recorded at four different heating rates are analyzed to determine the transition temperature, activation energy, thermal stability, glass forming ability, and dimensionality of growth during phase transformation. Present study shows that the thermal stability and the glass-forming ability increase with an increase in the Ag content which is in agreement with the earlier studies. Our results show that Se80.5Bi1.5Te16Ag2 composition is thermally more stable and has a little tendency to crystallize in comparison to other compositions under study. The increase in thermal stability with increasing Ag concentration is attributed to an increase in the cohesive energy. 相似文献
90.
We here experimentally demonstrate that gyration modes of coupled vortices can be resonantly excited primarily by the ac current in a pair of ferromagnetic disks with variable separation. The sole gyration mode clearly splits into higher and lower frequency modes via dipolar interaction, where the main mode splitting is due to a chirality sensitive phase difference in gyrations of the coupled vortices, whereas the magnitude of the splitting is determined by their polarity configuration. These experimental results show that the coupled pair of vortices behaves similar to a diatomic molecule with bonding and antibonding states, implying a possibility for designing the magnonic band structure in a chain or an array of magnetic vortex oscillators. 相似文献