全文获取类型
收费全文 | 908篇 |
免费 | 134篇 |
国内免费 | 79篇 |
专业分类
化学 | 777篇 |
晶体学 | 73篇 |
力学 | 3篇 |
综合类 | 6篇 |
数学 | 1篇 |
物理学 | 261篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 19篇 |
2021年 | 18篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 35篇 |
2015年 | 32篇 |
2014年 | 34篇 |
2013年 | 60篇 |
2012年 | 71篇 |
2011年 | 42篇 |
2010年 | 60篇 |
2009年 | 55篇 |
2008年 | 52篇 |
2007年 | 43篇 |
2006年 | 50篇 |
2005年 | 40篇 |
2004年 | 56篇 |
2003年 | 36篇 |
2002年 | 59篇 |
2001年 | 27篇 |
2000年 | 27篇 |
1999年 | 26篇 |
1998年 | 23篇 |
1997年 | 28篇 |
1996年 | 23篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1121条查询结果,搜索用时 15 毫秒
81.
82.
83.
Yu. V. Zorenko I. V. Konstankevich V. I. Gorbenko P. I. Yurchishin 《Journal of Applied Spectroscopy》2002,69(5):769-776
The possibility of obtaining scintillators with a high effective atomic number of the element Z
ef based on Lu3Al5O12:Ce3+ singlecrystal films (SCF) on doping with La3+ and Sc3+ ions on Y3Al5O12 substrates has been investigated. It is established that the SCF of (LuLaY)3Al5O12:Ce3+ (Z
ef = 58.9 and = 6.67 g/cm2) does not rank below those of Y3Al5O12:Ce3+ (Z
ef = 29 and = 4.52 g/cm2) in the conversion efficiency of radiation at the band with max = 515 nm. This allows their use as screens of xray images with a space resolution of 0.75–1.00 m. It is suggested that in the SCF of Lu3Al5O12 the isoelectronic impurities of lanthanum and scandium form radiative recombination centers of the type LaLu, ScLu, and ScAl as well as the centers Lu as a consequence of the effect of replacement of some Lu3+ ions by the La3+ ions to octanodes of the garnet lattice. The low efficiency of Ce3+ radiation in the SCF of (LuSc)3(AlSc)5O12:Ce is explained by substantial losses due to excitation of the recombination luminescence in the UV region of the centers formed by the isoelectronic impurities of scandium and to the possible existence of the channel of energy excitation dissipation related to the transitions between extrema of the allowed energy bands and activator levels. 相似文献
84.
85.
86.
87.
88.
Chitta?Ranjan?Patra Yitzhak?Mastai Aharon?GedankenEmail author 《Journal of nanoparticle research》2004,6(5):509-518
Submicrometer sized gallium oxide hydroxide (GaO(OH)) and gallium oxide (Ga2O3) rods have been successfully fabricated on a large scale by refluxing an aqueous solution of Ga(NO3)3 and NH4OH in a simple domestic microwave oven (DMO). The structures, morphologies, compositions and physical properties of the as–synthesized and calcined products have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), selected area energy dispersive X-ray spectroscopy (SAEDS), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and energy dispersive X-ray (EDX) analysis. TEM images show that submicrometer sized as–synthesized Ga O(OH) rods have diameters of 0.3–0.5 m and lengths of 3.2–3.5 m. The calcined product consists of submicrometer rods with diameters of 0.4–0.5 m and lengths of 5–5.5 m. XRD, EDX and SAED analysis together indicate that the as–synthesized product has an orthorhombic gallium oxide hydroxide (GaO(OH)) crystal structure, and that the calcined product is rhombohedral Ga2O3. A possible mechanism for the formation of submicrometer sized GaO(OH) rods is discussed briefly. 相似文献
89.
90.
IntroductionThechemistryoforganoaluminum,organogalliumandorganoindiumcomplexeshasattractedmuchat'tentionduenotonlytotheirinterestingstructuralandchemicalpropertiesbutalsotheirapplicationinsemiconductormaterialsl-5.InthecourseofourstudiesonexploringvolatileMOCVDprecursorsthathavethepropertiesoflowertoxicityandhigherstability,wehaverecentlyreportedonthesynthesisandcharacterizationofintermolecularadducts'-',novelbondingmodecomplexes",',andthecomplexesinwhichN/Omixed-donorcrownethersasligands'l'… 相似文献