全文获取类型
收费全文 | 91篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学 | 20篇 |
晶体学 | 1篇 |
数学 | 16篇 |
物理学 | 55篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有92条查询结果,搜索用时 31 毫秒
11.
An interferometer is described in which a rotatable Wollaston prism is used to achieve constant radial and azimuthal shears in a converging beam. These displacements may have applications in speckle shearing interferometry for the deformation measurement of objects with axial symmetry. 相似文献
12.
For the first time cesium diffusivity in aqueous solutions of rubidium chloride is being reported here in the concentration
range from 0.001 to 4.00 mol⋅dm−3. The measurement use a radioactive tracer technique employing a sliding cell mechanism. These diffusivity values were utilized
to understand the transport mechanism of Cs ion in the RbCl–H2O system using the Onsager-Gosting-Harned equation and the extended Debye-Hückel equation. The observed deviation between
the theoretical and experimental diffusivities are explained by introducing the concept of Field-Dielectric-Gradient forces
and energies that exist around an ion, which takes care of the finite size of the ion, ion-water interaction and the ion-ion
interaction in a continuum basis. 相似文献
13.
Estrogen induced proliferation of existing mutant cells is widely understood to be the major risk determining factor in the
development of breast cancer. Hence determination of the Estrogen Receptor[ER] status is of paramount importance. We have
carried out the synthesis and characterization of a novel NIR fluorescent dye conjugate aimed at measuring ER+ve status in-vivo.
The conjugate was synthesized by ester formation between 17-β estradiol and a cyanine dye namely: bis-1, 1-(4-sulfobutyl)
indotricarbocyanine-5-carboxylic acid, sodium salt. The replacement of the sodium ion in the ester by a larger glucosammonium
ion was found to enhance the hydrophilicity and reduce the toxic effect on cell lines. The excitation and emission peaks for
the dye were recorded as 750 and 788 nm respectively; ideal for non-invasive optical imaging owing to minimal tissue attenuation
and auto-fluorescence at these wavelengths. The dye (NIRDC1) has a significant drop in plasma-protein binding therefore leading to marked improvement in pharmacokinetic profile such
as dye evacuation in comparison to ICG. In addition the dye showed enhanced fluorescence quantum yield, molar extinction coefficient
and linearity in fluorescence relative to ICG. This dye can be potentially used as a target specific exogenous contrast agent
in molecular optical imaging for early detection of breast cancer. 相似文献
14.
Sławomir Prucnal Marcin Turek Andrzej Drozdziel Krzysztof Pyszniak Artur Wójtowicz Sheng-Qiang Zhou Alohe Kanjilal Artem Shalimov Wolfgang Skorupa Jerzy Zuk 《Central European Journal of Physics》2011,9(2):338-343
The InAs quantum structures were formed in silicon by sequential ion implantation and subsequent thermal annealing. Two kinds of crystalline InAs nanostructures were successfully synthesized: nanodots (NDs) and nanopyramids (NPs). The peaks at 215 and 235 cm?1, corresponding to the transverse optical (TO) and longitudinal optical (LO) InAs single-phonon modes, respectively, are clearly visible in the Raman spectra. Moreover, the PL band at around 1.3 µm, due to light emission from InAs NDs with an average diameter 7±2 nm, was observed. The InAs NPs were found only in samples annealed for 20 ms at temperatures ranging from 1000 up to 1200°C. The crystallinity and pyramidal shape of InAs quantum structures were confirmed by HRTEM and XRD techniques. The average size of the NPs is 50 nm base and 50 nm height, and they are oriented parallel to the Si (001) planes. The lattice parameter of the NPs increases from 6.051 to 6.055 Å with the annealing temperature increasing from 1100 to 1200°C, due to lattice relaxation. Energy dispersive spectroscopy (EDS) shows almost stoichiometric composition of the InAs NPs. 相似文献
15.
We consider a class of two-stage stochastic integer programs with binary variables in the first stage and general integer variables in the second stage. We develop decomposition algorithms akin to the $L$ -shaped or Benders’ methods by utilizing Gomory cuts to obtain iteratively tighter approximations of the second-stage integer programs. We show that the proposed methodology is flexible in that it allows several modes of implementation, all of which lead to finitely convergent algorithms. We illustrate our algorithms using examples from the literature. We report computational results using the stochastic server location problem instances which suggest that our decomposition-based approach scales better with increases in the number of scenarios than a state-of-the art solver which was used to solve the deterministic equivalent formulation. 相似文献
16.
17.
Oncogenes and Tumor Suppressor Genes in Photocarcinogenesis 总被引:3,自引:0,他引:3
18.
S. Chandramohan A. Kanjilal S. N. Sarangi S. Majumder R. Sathyamoorthy T. Som 《Applied Physics A: Materials Science & Processing》2010,99(4):837-842
We report on effects of Fe implantation doping-induced changes in structural, optical, morphological, and vibrational properties
of cadmium sulfide thin films. Films were implanted with 90 keV Fe+ ions at room temperature for a wide range of fluences from 0.1×1016 to 3.6×1016 ions cm−2 (corresponding to 0.38–12.03 at.% of Fe). Glancing angle X-ray diffraction analysis revealed that the implanted Fe atoms
tend to supersaturate by occupying the substitutional cationic sites rather than forming metallic clusters or secondary phase
precipitates. In addition, Fe doping does not lead to any structural phase transformation although it induces structural disorder
and lattice contraction. Optical absorption studies show a reduction in the optical band gap from 2.39 to 2.17 eV with increasing
Fe concentration. This is attributed to disorder-induced band tailing in semiconductors and ion-beam-induced grain growth.
The strain associated with a lattice contraction is deduced from micro-Raman scattering measurements and is found that size
and shape fluctuations of grains, at higher fluences, give rise to inhomogeneity in strain. 相似文献
19.
Indium phosphide sample was irradiated with 200?MeV Ag9+ ions for the fluence of 2?×?1013?ions?cm?2. The sample was chemically etched down up to 240?nm depth to investigate the distribution of defects at different regions. Raman scattering and glancing incidence X-ray diffraction spectra were recorded at different depths. The stress estimated from Raman shift was found to increase with depth up to 160?nm and thereafter it decreased and at a depth of 224?nm sample did not show any stress. Phonon coherence length estimated from the Phonon Confinement Model was found to vary between 43 and 18?nm with respect to depth. Glancing incidence X-ray diffraction results revealed the decrease in crystallite size from 16.12 to 1.00?nm in different depth regions. 相似文献
20.
ABSTRACTIn the present work, effects of silicon negative ion implantation into semi-insulating gallium arsenide (GaAs) samples with fluences varying between 1?×?1015 and 4?×?1017?ions?cm?2 at 100?keV have been described. Atomic force microscopic images obtained from samples implanted with fluence up to 1?×?1017?ion?cm?2 showed the formation of GaAs clusters on the surface of the sample. The shape, size and density of these clusters were found to depend on ion fluence. Whereas sample implanted at higher fluence of 4?×?1017?ions?cm?2 showed bump of arbitrary shapes due to cumulative effect of multiple silicon ion impact with GaAs on the same place. GXRD study revealed formation of silicon crystallites in the gallium arsenide sample after implantation. The silicon crystallite size estimated from the full width at half maxima of silicon (111) XRD peak using Debye-Scherrer formula was found to vary between 1.72 and 1.87?nm with respect to ion fluence. Hall measurement revealed the formation of n-type layer in gallium arsenide samples. The current–voltage measurement of the sample implanted with different fluences exhibited the diode like behavior. 相似文献