全文获取类型
收费全文 | 166篇 |
免费 | 5篇 |
专业分类
化学 | 115篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 12篇 |
物理学 | 40篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 4篇 |
2020年 | 11篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 14篇 |
2011年 | 15篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 1篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1970年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有171条查询结果,搜索用时 15 毫秒
81.
Lorenzo Di Sipio G. De Michelis Elisabetta Baiocchi Gianluigi Ingletto 《Transition Metal Chemistry》1980,5(1):164-167
Summary The polarized electronic absorption spectrum of [FeO4]2– has been measured at liquid helium temperature using single crystals of K2CrO4 doped with the ferrate(VI) ion and a new band has been observed at 9112 cm–1. An interpretation of the spectrum in the 9000-22000 cm–1 range is given by considering the possible ligand field transition under the crystal site perturhation. 相似文献
82.
Tullio Pilati Gianluigi Casalone 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):495-496
(5S,9S,17S)‐17‐Hydroxy‐9(10→5)‐abeo‐estr‐4‐ene‐3,10‐dione, C18H26O3, (II), and (5R,9R,17S)‐17‐hydroxy‐9(10→5)‐abeo‐estr‐4‐ene‐3,10‐dione, C18H26O3, (III), are equimolecular products of the FeII‐induced transposition of 10β‐hydroperoxy‐17β‐hydroxyestr‐4‐en‐3‐one, (I). With respect to reagent molecules, the configuration at C9 is retained for (II) while it is inverted in (III). The conformations of the five‐ and six‐membered rings are compared. 相似文献
83.
We study non reflexive Orlicz spaces \(L^\varPsi \) and their Morse subspace \(M^\varPsi \), i.e. the closure of \(L^\infty \) in \(M^\varPsi \) to determine when \((M^\varPsi ,L^\varPsi )\) can be described as having an o–O type structure with respect to an equivalent norm on \(L^\varPsi \). Examples of classes of Young functions for which the answer is affirmative are provided, but also examples are given to show that this is not possible for all non-reflexive Orlicz spaces. An equivalent expression of the distance in \(L^\varPsi \) to \(M^\varPsi \), induced by the new norm, is also provided.
相似文献84.
85.
86.
Sepe V Ummarino R D'Auria MV Lauro G Bifulco G D'Amore C Renga B Fiorucci S Zampella A 《Organic & biomolecular chemistry》2012,10(31):6350-6362
Seven synthetic analogues of the PXR (pregnane-X-receptor) potent natural agonist solomonsterol A were prepared by total synthesis. Their activity toward PXR was assessed by transactivation and RT-PCR assays. The study discloses cholestan disulfate (8) as a new, simplified agonist of PXR. By in vitro studies on hepatic cells we have demonstrated that this compound is a potent PXR agonist and functional characterization in human macrophages and hepatic stellate cells provided evidence that cholestan disulfate (8) has the ability to modulate the immune response triggered by bacterial endotoxin as well as to counter-activate hepatic stellate cell activation induced by thrombin. Because inhibition of immune-driven circuits might have relevance in the treatment of inflammation and liver fibrosis, the present data support the development of cholestan disulfate (8) in preclinical models of inflammatory diseases. 相似文献
87.
The purpose of this paper is to study the dynamics of a square billiard with a non-standard reflection law such that the angle of reflection of the particle is a linear contraction of the angle of incidence. We present numerical and analytical arguments that the nonwandering set of this billiard decomposes into three invariant sets, a parabolic attractor, a chaotic attractor, and a set consisting of several horseshoes. This scenario implies the positivity of the topological entropy of the billiard, a property that is in sharp contrast with the integrability of the square billiard with the standard reflection law. 相似文献
88.
Penoni A Palmisano G Broggini G Kadowaki A Nicholas KM 《The Journal of organic chemistry》2006,71(2):823-825
[reaction: see text] N-Methoxyindoles are produced in moderate to excellent yields from the reaction between nitrosoarenes and alkynes in the presence of K2CO3/(CH3)2SO4. Terminal alkynes with conjugating substituents afford 3-substituted N-methoxyindoles exclusively. The analogous reactions with methyl propiolate provide a one-step preparation of phytoalexin analogues from Wasabi. 相似文献
89.
90.
Renxu Chen Wei Feng Shiping Zhu Gianluigi Botton Beng Ong Yiliang Wu 《Journal of polymer science. Part A, Polymer chemistry》2006,44(3):1252-1262
Poly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA), a partially fluorinated polymer, was directly grafted from silicon wafer surfaces by a surface‐initiated atom‐transfer radical polymerization (ATRP). The polymer layer thickness increased linearly with monomer conversion and molecular weight of free polymers in solution. The thickness was mainly determined by the experimental conditions such as activator/deactivator ratio, monomer/catalyst ratio, and monomer concentration. PTFEMA layers of more than 100‐nm thick were obtained. The grafted PTFEMA chains were “living” and allowed the extension of a second block of PMMA. X‐ray photoelectron spectroscopy study showed that the chemical compositions at the surfaces agreed well with their theoretical values. A novel surface‐attachable difunctional initiator was also synthesized and applied to the grafting of PTFEMA. The grafting density was doubled using this difunctional initiator, from 0.48 to 0.86 chains/nm2. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1252–1262, 2006 相似文献