全文获取类型
收费全文 | 244篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 114篇 |
晶体学 | 1篇 |
力学 | 4篇 |
数学 | 18篇 |
物理学 | 115篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 15篇 |
2012年 | 16篇 |
2011年 | 13篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 13篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有252条查询结果,搜索用时 15 毫秒
111.
The behavior of an ionic liquid (IL) within aqueous micellar solutions is governed by its unique property to act as both an electrolyte and a cosolvent. The influence of the surfactant structure on the properties of aqueous micellar solutions of zwitterionic SB‐12, nonionic Brij‐35 and TX‐100, and anionic sodium dodecyl sulfate (SDS) in the presence of the “hydrophobic” IL 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim][PF6]) is assessed along with the possibility of forming oil‐in‐water microemulsions in which the IL acts as the “oil” phase. The solubility of [bmim][PF6] within aqueous micellar solutions increases with increasing surfactant concentration. In contrast to anionic SDS, the zwitterionic and nonionic surfactant solutions solubilize more [bmim][PF6] at higher concentrations and the average aggregate size remains almost unchanged. The formation of IL‐in‐water microemulsions when the concentration of [bmim][PF6] is above its aqueous solubility is suggested for nonionic Brij‐35 and TX‐100 aqueous surfactant solutions. 相似文献
112.
We present ab initio calculations which show that the direct-band-gap, effective masses and Fermi velocities of charge carriers in ZnO monolayer (ML-ZnO) in graphene-like honeycomb structure are all tunable by application of in-plane homogeneous biaxial strain. Within our simulated strain limit of ±10%, the band gap remains direct and shows a strong non-linear variation with strain. Moreover, the average Fermi velocity of electrons in unstrained ML-ZnO is of the same order of magnitude as that in graphene. The results promise potential applications of ML-ZnO in mechatronics/straintronics and other nano-devices such as the nano-electromechanical systems (NEMS) and nano-optomechanical systems (NOMS). 相似文献
113.
1,8-Diazacubane-templated nickel(II) sulfate with the Kagome structure prepared under solvothermal conditions exhibits interesting magnetic properties. 相似文献
114.
Lithium-doped zinc oxide films were synthesized by spray pyrolysis technique, and their structural and optical properties
were characterized by X-ray diffraction, transmission electron microscope, atomic force microscope, and photoluminescence
spectroscopy. The effect of doping on the photoluminescence properties was investigated at room temperature (300 K). Polycrystalline
nature of the films was confirmed from X-ray diffraction and electron microscopic studies. A two-dimensional fringe moiré
pattern with spacing of 1.2 nm was observed for the doped thin film. Lithium doping has been found to increase the roughness
of the surface, thus making the film more passivated. Lithium was found to play a key role in the excitonic as well as visible
luminescence of ZnO. 相似文献
115.
We present here a theoretical study of the effect of Jahn-Teller(J-T) distortion on the self-energy of electrons in the CMR
manganites. The model consists of the itinerant e
g
electrons distorted by J-T effect and the localized t
2g
core electrons carrying strong ferromagnetism due to Hund’s rule. The phonon interacts with the e
g
electrons as well as the J-T distorted e
g
band. The electron Green’s functions are calculated by Zubarev’s technique. The electron self-energy which carries all the
information of the model is calculated from the Green’s function. The effect of J-T distortion, magnetism on the frequency
and temperature dependent dynamic self-energy is presented in this paper. The results are discussed. 相似文献
116.
Dipanjali Behera Sunil K. Tripathy Tushar R. Routray 《International Journal of Theoretical Physics》2010,49(10):2569-2581
Bulk Viscous anisotropic Bianchi-III cosmological models are investigated with time dependent gravitational and cosmological
constants in the framework of Einstein’s general relativity. In order to get some useful information about the time varying
nature of G and Λ, we have assumed an exponentially decaying rest energy density of the universe. The extracted Newtonian gravitational
constant G varies with time but its time varying nature depends on bulk viscosity and the anisotropic nature of the model. The cosmological
constant Λ is found to decrease with time to a small but positive value for the models. 相似文献
117.
In this communication, we develop the microscopic theory of Raman spectra of the heavy fermion (HF) system in its normal state at low temperatures. The system is described by the Periodic Anderson Model along with the coupling of the phonon to the bare f-electrons as well as to the hybridization between the conduction band and the f-electrons. The phonon Green's function and the phonon self-energy are evaluated by the equations of motion method of Zubarev. The phonon spectral density function (SDF) is evaluated at low temperatures in the long wavelength limit. The calculation depicts three Raman active modes one of which corresponds to the strongly renormalized phonon at the value of the reduced frequency ) around 0.57 denoted as (P0), and the other two at low reduced frequencies of and in the SDF. The effect of electron–phonon (EP) coupling on Raman excitation peaks is investigated to probe the nature of the electronic states of the system. 相似文献
118.
N. Mărginean S.M. Lenzi A. Gadea E. Farnea S.J. Freeman D.R. Napoli D. Bazzacco S. Beghini B.R. Behera P.G. Bizzeti A. Bizzeti-Sona D. Bucurescu R. Chapman L. Corradi A.N. Deacon G. de Angelis F. Della Vedova E. Fioretto M. Ionescu-Bujor A. Iordachescu Th. Kröll A. Latina X. Liang S. Lunardi G. Montagnoli R. Mărginean M. Nespolo G. Pollarolo C. Rusu F. Scarlassara J.F. Smith K. Spohr A.M. Stefanini S. Szilner M. Trotta C.A. Ur B.J. Varley W. Zhimin 《Physics letters. [Part B]》2006
119.
The paper describes HPLC, UV spectrophotometric and non aqueous titrimetric method for the estimation of poorly water soluble protease inhibitor. Ritonavir in raw material and tablet dosage form. HPLC analysis was carried out in a C18 column using acetonitrile, methanol, and buffer in the ratio 60: 20: 20 (v/v/v) at 240 nm. For the spectrophotometric determination, methanolic solution of Ritonavir was reacted with 3-methyl benzothiazolin-2-one hydrazone (MBTH). The oxidative coupled green coloured chromogen was analysed at 633 nm. Non aqueous titration was carried out using perchloric acid as titrant and the end point was determined using crystal violet as indicator. The three methods were validated and statistically evaluated to correlate the difference between the methods for estimation of Ritonavir in pharmaceutical dosage form. 相似文献
120.