全文获取类型
收费全文 | 317篇 |
免费 | 3篇 |
专业分类
化学 | 200篇 |
晶体学 | 1篇 |
力学 | 8篇 |
数学 | 31篇 |
物理学 | 80篇 |
出版年
2021年 | 4篇 |
2018年 | 4篇 |
2016年 | 4篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 6篇 |
2008年 | 15篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 14篇 |
1998年 | 6篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1987年 | 13篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1968年 | 4篇 |
1967年 | 2篇 |
1966年 | 3篇 |
1963年 | 2篇 |
1960年 | 2篇 |
1955年 | 2篇 |
1954年 | 2篇 |
排序方式: 共有320条查询结果,搜索用时 93 毫秒
91.
Summary The kinetics and mechanism of the system: [FeL(OH)]2–n + 5 CN– [Fe(CN)5(OH)]3– + Ln–, where L=DTPA or HEDTA, have been investigated at pH= 10.5±0.2, I=0.25 M and t=25±0.1 C.As in the reaction of [FeEDTA(OH)]2–, the formation of [Fe(CN)5(OH)]3– through the formation of mixed ligand complex intermediates of the type [FeL(OH)(CN)x]2–n–x, is proposed. The reactions were found to consist of three observable stages. The first involves the formation of [Fe(CN)5(OH)]3–, the second is the conversion of [Fe(CN)5(OH)]3– into [Fe(CN)6]3– and the third is the reduction of [Fe(CN)6]3– to [Fe(CN)6]4– by oxidation of Ln– The first reaction exhibits a variable order dependence on the concentration of cyanide, ranging from one at high cyanide concentration to three at low concentration. The transition between [FeL(OH)]2–n and [Fe(CN)5(OH)]3– is kinetically controlled by the presence of four cyanide ions around the central iron atom in the rate determining step. The second reaction shows first order dependence on the concentration of [Fe(CN)5(OH)]3– as well as on cyanide, while the third reaction follows overall second order kinetics; first order each in [Fe(CN)6]3– and Ln–, released in the reaction. The reaction rate is highly dependent on hydroxide ion concentration.The reverse reaction between [Fe(CN)5(OH)]3– and Ln– showed an inverse first order dependence on cyanide concentration along with first order dependence each on [Fe(CN)5– (OH)]3– and Ln–. A five step mechanism is proposed for the first stage of the above two systems. 相似文献
92.
An enantiospecific route to the previously unreported 1,6-difunctionalized dodecahydrobenz[f]indene ring system is described. Optically pure Hajos-Parrish ketone is used as the building block for preparation of a 6-methyleneinden-5-ol. This allylic alcohol is then utilized in a Claisen rearrangement under Johnson's conditions to introduce a side chain that is further modified and cyclized to produce the benz[f]indene ring system. 相似文献
93.
94.
95.
96.
97.
98.
99.
Amar Nath Nigam 《Zeitschrift für Physik A Hadrons and Nuclei》1957,147(3):264-270
Possible correlations of the energy levels arising due to colour centers in a potassium halide crystal with the X-ray absorptions fine structure of potassium ion are discussed. Influence of the inner ionisation on the activation energy of the ions and on the potential surrounding them has been estimated using approximate equations. 相似文献
100.
A parton model for the virtual photon process γ → X is examined. It is assumed that a scaling property applies and the total cross section is σγγ→X = s?1φ(ξ), where the function ? is dependent on the scaling variable ξ defined by ξ = s/(q21q22). The cross section for the process ee → + X is calculated using the equivalent-photon technique. 相似文献