全文获取类型
收费全文 | 233篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
化学 | 180篇 |
晶体学 | 7篇 |
力学 | 3篇 |
数学 | 33篇 |
物理学 | 20篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 17篇 |
2011年 | 17篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 22篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 16篇 |
2001年 | 5篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1960年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有243条查询结果,搜索用时 15 毫秒
31.
Colette Lacabanne Patrice Goyaud Raymond F. Boyer 《Journal of Polymer Science.Polymer Physics》1980,18(2):277-284
The thermally stimulated current (TSC) technique has been used to investigate three anionic polystyrenes of M?n 17,000, 71,700, and 1.55 × 106, i.e., M < Mc, M > Mc, and M ? Mc, where Mc is the entanglement molecular weight. A current maximum near Tg designated TMg, has relaxation times which follow an Arrhenius equation. A second current maximum at T > Tg appears to be the Tll process and is designated TMll. Relaxation times for it follow a Vogel equation. TMg and TMll vary with molecular weight, increasing below Mc and leveling off above Mc at a temperature of about 170°C. Values of TMg and TMll are compared with values of Tg and Tll obtained from torsional braid analysis, which involves melt flow; and with differential-scanning-calorimetric values on fused films, where there is no transport of polymer. It is concluded from such cross-comparisons that TSC, at least for polystyrene, is a quasistatic test which may involve microscopic viscosity. Macroscopic viscosity does not play a role. The ratio TMll/TMg is in the range 1.10–1.16, similar to Tll/Tg values by other methods. A few comments about Tll in atactic poly(methyl methacrylate) by the TSC method are given. 相似文献
32.
Ondrej Stranik Daniela Iacopino Robert Nooney Colette McDonagh Brian D. MacCraith 《Journal of fluorescence》2010,20(1):215-223
In this paper, we describe a novel technique for depositing metal nanoparticles (NPs) on a planar substrate whereby the NPs
are micro-patterned on the surface by a simple stamp-printing procedure. The method exploits the attractive force between
negatively charged colloidal metal NPs and positively-charged polyelectrolyte layers which have been selectively deposited
on the surface. Using this technique, large uniform areas of patterned metal NPs, with different plasmonic properties, were
achieved by optimisation of the stamping process. We report the observation of unusual fluorescence emission from these structures.
The emission was measured using epifluorescence microscopy. Fluorescence lifetime behaviour was also measured. Furthermore,
the μ-patterned NPs exhibited blinking behaviour under 469 nm excitation and the fluorescence spectrum was multi-peaked. It
has been established that the fluorescence is independent of the plasmon resonance properties of the NPs. As well as optimising
the novel NP μ-patterning technique, this work discusses the origin and characteristics of the anomalous fluorescence behaviour
in order to characterise and minimise this unwanted background contribution in the use of metal NPs for plasmonic enhancement
of fluorescence for optical biochip applications. 相似文献
33.
Dandurand Jany Samouillan Valérie Lacabanne Colette Pepe Antonietta Bochicchio Brigida 《Journal of Thermal Analysis and Calorimetry》2018,131(2):1323-1332
Journal of Thermal Analysis and Calorimetry - Elastin fibrillogenesis is conditioned by multiple self-assembly processes. Previous studies have evidenced the crucial influence of amino acid... 相似文献
34.
Variability of UV irradiance in Europe 总被引:1,自引:1,他引:0
Seckmeyer G Pissulla D Glandorf M Henriques D Johnsen B Webb A Siani AM Bais A Kjeldstad B Brogniez C Lenoble J Gardiner B Kirsch P Koskela T Kaurola J Uhlmann B Slaper H den Outer P Janouch M Werle P Gröbner J Mayer B de la Casiniere A Simic S Carvalho F 《Photochemistry and photobiology》2008,84(1):172-179
35.
Kerwyn G. Alley Roland Bircher Hans U. Güdel Boujemaa Moubaraki Keith S. Murray Brendan F. Abrahams Colette Boskovic 《Polyhedron》2007
The reaction of Ni(OAc)2, NiX2 (X = Cl, Br) or CoCl2 with the proligand 2-amino-2-methyl-1,3-propanediol (ampdH2) affords a new family of tetranuclear complexes. The syntheses of [Ni4(OAc)4(ampdH)4] (1) and [M4X4(ampdH)4] (M = Ni, X = Cl, 2; M = Ni, X = Br, 3; M = Co, X = Cl, 4) are reported, together with the single crystal X-ray structures of 1, 2 and 4 and the magnetochemical characterization of 1, 3 and 4. Each member of this family of complexes displays a low symmetry structure that incorporates a {M4O4} core unit based on a distorted cubane. Magnetic measurements reveal ferromagnetic exchange interactions for 1, 3 and 4. These give rise to S = 4 ground state spins for the tetranuclear Ni complexes and an anisotropic effective S′ = 2 ground state for the Co complex. 相似文献
36.
Covalent assembly between gold-thiolate nanoparticles (AuNPs) and the cluster [Fe(eta(5)-C(5)H(5))(mu(3)-CO)](4), 1, can be achieved either by direct Brust-Schriffin-type synthesis using a mixture of undecanethiol and a thiol functionalized with , or by substitution of undecanethiolate ligands in AuNPs by thiolate ligands functionalized with ; cyclic voltammetry of these AuNPs functionalized with allows us to recognize and titrate the oxo-anions H(2)PO(4)(-) and ATP(2-). 相似文献
37.
Razavet M Artero V Cavazza C Oudart Y Lebrun C Fontecilla-Camps JC Fontecave M 《Chemical communications (Cambridge, England)》2007,(27):2805-2807
The reaction of the new and structurally characterized covalent {Mn(CO)(3)(H(2)O)(2)}(+)-lysozyme adduct with NiS(4) and NiN(2)S(2) complexes generates binuclear Ni-Mn complexes; relevance to the reactivity of the protein-bound {Fe(CO)(CN)(2)} intermediate during maturation of [NiFe] hydrogenases is discussed. 相似文献
38.
39.
40.
Boskovic C Sieber A Chaboussant G Güdel HU Ensling J Wernsdorfer W Neels A Labat G Stoeckli-Evans H Janssen S 《Inorganic chemistry》2004,43(16):5053-5068
Nine members of a new family of polynuclear ferric complexes have been synthesized and characterized. The reaction of Fe(O(2)CMe)(2) with polydentate Schiff base proligands (H(2)L) derived from salicylidene-2-ethanolamine, followed in some cases by reaction with carboxylic acids, has afforded new complexes of general formulas [Fe(2)(pic)(2)(L)(2)] (where pic(-) is the anion of 2-picolinic acid), [Fe(3)(O(2)CMe)(3)(L)(3)], [Fe(4)(OR)(2)(O(2)CMe)(2)(L)(4)], and [Fe(5)O(OH)(O(2)CR)(4)(L)(4)]. The tri-, tetra-, and pentanuclear complexes all possess unusual structures and novel core topologies. M?ssbauer spectroscopy confirms the presence of high-spin ferric centers in the tri- and pentanuclear complexes. Variable-temperature magnetic measurements suggest spin ground states of S = 0, 1/2, 0, and 5/2 for the bi-, tri-, tetra-, and pentanuclear complexes, respectively. Fits of the magnetic susceptibility data have provided the magnitude of the exclusively antiferromagnetic exchange interactions. In addition, an easy-axis-type magnetic anisotropy has been observed for the pentanuclear complexes, with D values of approximately -0.4 cm(-)(1) determined from modeling the low-temperature magnetization data. A low-temperature micro-SQUID study of one of the pentanuclear complexes reveals magnetization hysteresis at nonzero field. This is attributed to an anisotropy-induced energy barrier to magnetization reversal that is of molecular origin. Finally, an inelastic neutron scattering study of one of the trinuclear complexes has revealed that the magnetic behavior arises from two distinct species. 相似文献