全文获取类型
收费全文 | 191篇 |
免费 | 5篇 |
专业分类
化学 | 102篇 |
晶体学 | 9篇 |
力学 | 1篇 |
数学 | 19篇 |
物理学 | 65篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 14篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 7篇 |
1999年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1968年 | 2篇 |
1966年 | 1篇 |
1958年 | 1篇 |
1955年 | 1篇 |
1944年 | 1篇 |
1942年 | 3篇 |
排序方式: 共有196条查询结果,搜索用时 93 毫秒
51.
An analysis of the effects of two different techniques of spatial-division multiplexing on the quality of the image reconstructed by the hologram of a diffusing object is presented, along with some experimental results obtained with a coherent optical system under diffraction-limited conditions. These show that the use of random masks for spatial division in the cases studied gives much poorer resolution than simple sub-division of the hologram area, because of the serious loss of image contrast with a random mask. 相似文献
52.
P. Hariharan 《Optics Communications》1976,17(1):52-54
Reflection holograms recorded on photographic materials usually reconstruct an image at a shorter wavelength than that at which they were recorded. As a result, the lateral and longitudinal magnifications of the reconstructed image are not the same and the image appears distorted. It is shown that this distortion can be minimized by a proper choice of the recording geometry. The residual aberrations of the image are discussed. 相似文献
53.
Liu Y Kravtsov V Walsh RD Poddar P Srikanth H Eddaoudi M 《Chemical communications (Cambridge, England)》2004,(24):2806-2807
A novel anionic metal-organic cube (MOC-1), [Ni(8)(HImDC)(12)](8-), has been synthesized by metal-ligand directed assembly of eight tri-connected Ni nodes and twelve doubly deprotonated bis(bidentate) imidazoledicarboxylic acid ligands (HImDC). 相似文献
54.
55.
56.
Amrtha BhideK. Hariharan 《Solid State Ionics》2011,192(1):360-363
An intercalation compound with composition Na0.7CoO2 has been synthesized through different preparative techniques such as solid state reaction, ball milling and sol gel techniques. The investigation reveals that the cathode material with an average particle size of about 500 nm of uniform morphology can be synthesized through sol gel technique. Further, this synthesis technique improves the stoichiometry of the sodium content significantly. The electrical resistivity of these cathode materials is found to be in the range of 4 to 12 mΩ-cm at 300 K. It has been observed that, the resistivity of the cathode material increases with increase in sodium content. The electrochemical cells with the configuration Na | [wt.% 0.3 PEO-0.7 PEG]6:NaPO3 |composite cathode material, have shown an open circuit voltage (OCV) value of 2.7 V. The (OCV) of the cells with the cathode prepared by sol-gel and ball milling route has shown a plateau region of about 40 h, when compared to the plateau region of 10 h for the battery with the cathode prepared by solid state reaction. The reduction in the particle size of the cathode material has improved the stability of the electrode electrolyte interface and thereby discharges characteristics. 相似文献
57.
P. Hariharan 《Optics & Laser Technology》2002,34(7):8557-511
Apochromatic retarders can be constructed by using a combination of three plates of different birefringent materials with properly chosen thicknesses. However, when dealing with a broad wavelength range, their performance depends very much on the materials chosen. A procedure is presented for optimizing the choice of materials for such a broad-band retarder. 相似文献
58.
59.
R Nirmala V Sankaranarayanan K Sethupathi AV Morozkin T Geethakumary Y Hariharan 《Pramana》2002,58(5-6):1101-1104
New R
2Ti3Ge4 (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac
magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize
in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series.
The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales
with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays
a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects. 相似文献
60.