全文获取类型
收费全文 | 181篇 |
免费 | 10篇 |
国内免费 | 3篇 |
专业分类
化学 | 79篇 |
力学 | 6篇 |
数学 | 30篇 |
物理学 | 36篇 |
无线电 | 43篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 11篇 |
2013年 | 11篇 |
2012年 | 14篇 |
2011年 | 16篇 |
2010年 | 17篇 |
2009年 | 9篇 |
2008年 | 22篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1948年 | 1篇 |
1909年 | 2篇 |
1908年 | 1篇 |
1905年 | 4篇 |
1888年 | 1篇 |
1883年 | 1篇 |
1872年 | 2篇 |
排序方式: 共有194条查询结果,搜索用时 0 毫秒
131.
132.
Ville Jokinen Susanna Aura Laura Luosujärvi Lauri Sainiemi Tapio Kotiaho Sami Franssila Marc Baumann 《Journal of the American Society for Mass Spectrometry》2009,20(9):1723-1730
Matrix-free laser desorption/ionization was studied on two-layered sample plates consisting of a substrate and a thin film
coating. The effect of the substrate material was studied by depositing thin films of amorphous silicon on top of silicon,
silica, polymeric photoresist SU-8, and an inorganic-organic hybrid. Des-arg9-bradykinin signal intensity was used to evaluate the sample plates. Silica and hybrid substrates were found to give superior
signals compared with silicon and SU-8 because of thermal insulation and compatibility with amorphous silicon deposition process.
The effect of surface topography was studied by growing amorphous silicon on hybrid micro- and nanostructures, as well as
planar hybrid. Compared with planar sample plates, micro- and nanostructures gave weaker and stronger signals, respectively.
Different coating materials were tested by growing different thin film coatings on the same substrate. Good signals were obtained
from titania and amorphous silicon coated sample plates, but not from alumina coated, silicon nitride coated, or uncoated
sample plates. Overall, the strongest signals were obtained from oxygen plasma treated and amorphous silicon coated inorganic-organic
hybrid, which was tested for peptide-, protein-, and drug molecule analysis. Peptides and drugs were analyzed with little
interference at low masses, subfemtomole detection levels were achieved for des-arg9-bradykinin, and the sample plates were also suitable for ionization of small proteins. 相似文献
133.
P. Engel und J. Ville 《Fresenius' Journal of Analytical Chemistry》1883,22(1):82-83
Ohne Zusammenfassung 相似文献
134.
Ashby Wedell M. Dechan R. Engel J. Ville G. Lunge Berthelot Ch. Blarez A. Joly O. N. Witt R. von Höslin E. Jacobsen Rowland Williams Watson Smith P. Julius Menschutkin E. Léger G. Vulpius Ludwig Storch B. Fischer O. Philipp Theodor Lehmann Julius Petri M. C. Traub C. Hock G. Burkhard E. Bosetti Robert T. Thomson Harry Napier Draper C. Draper J. H. Long Carpenter F. Stolba und Eugen Dietrich 《Fresenius' Journal of Analytical Chemistry》1888,27(1):36-61
Ohne Zusammenfassung 相似文献
135.
Auerbach H. Friedenthal J. Ville E. Derrien A. Herrmann V. Ducceschi E. Buchner Sigward Mitscherlich M. Bial P. Mayer Brat E. C. van Leersum B. Reinbold O. Amrein J. Ostori E. Riegler H. L. Visser Jos Bilinski H. Held A. Berg Rud Ofner C. Neuberg O. Wentzki O. Folin H. Bellocq 《Analytical and bioanalytical chemistry》1905,44(6-7):455-459
136.
Designs, Codes and Cryptography - In this article, we study locating-dominating codes in binary Hamming spaces $$mathbb {F}^n$$ . Locating-dominating codes have been widely studied since their... 相似文献
137.
Raphael Lauenstein Sophie L. Mader Henrieta Derondeau Oaikhena Z. Esezobor Matthias Block Armin J. Rmer Christian Jandl Eberhard Riedle Ville R. I. Kaila Jürgen Hauer Erling Thyrhaug Corinna R. Hess 《Chemical science》2021,12(21):7521
Photoredox catalysts are integral components of artificial photosystems, and have recently emerged as powerful tools for catalysing numerous organic reactions. However, the development of inexpensive and efficient earth-abundant photoredox catalysts remains a challenge. We here present the photochemical and photophysical properties of a Ni–Mabiq catalyst ([NiII(Mabiq)]OTf (1); Mabiq = 2-4:6-8-bis(3,3,4,4-tetramethyldihydropyrrolo)-10-15-(2,2-biquinazolino)-[15]-1,3,5,8,10,14-hexaene1,3,7,9,11,14-N6)—and of a Zn-containing analogue ([ZnII(Mabiq)OTf] (2))—using steady state and time resolved optical spectroscopy, time-dependent density functional theory (TDDFT) calculations, and reactivity studies. The Ni and Zn complexes exhibit similar absorption spectra, but markedly different photochemical properties. These differences arise because the excited states of 2 are ligand-localized, whereas metal-centered states account for the photoactivity of 1. The distinct properties of the Ni and Zn complexes are manifest in their behavior in the photo-driven aza-Henry reaction and oxidative coupling of methoxybenzylamine.The development of earth-abundant photoredox catalysts remains a challenge. Studies of Ni- and Zn-Mabiq complexes demonstrate how the coordinating metal ion influences the photochemistry, photodynamics and reactivity of photocatalysts. 相似文献
138.
Ohne Zusammenfassung 相似文献
139.
140.
Van De Ville D. Blu T. Unser M. Philips W. Lemahieu I. Van de Walle R. 《IEEE transactions on image processing》2004,13(6):758-772
This paper proposes a new family of bivariate, nonseparable splines, called hex-splines, especially designed for hexagonal lattices. The starting point of the construction is the indicator function of the Voronoi cell, which is used to define in a natural way the first-order hex-spline. Higher order hex-splines are obtained by successive convolutions. A mathematical analysis of this new bivariate spline family is presented. In particular, we derive a closed form for a hex-spline of arbitrary order. We also discuss important properties, such as their Fourier transform and the fact they form a Riesz basis. We also highlight the approximation order. For conventional rectangular lattices, hex-splines revert to classical separable tensor-product B-splines. Finally, some prototypical applications and experimental results demonstrate the usefulness of hex-splines for handling hexagonally sampled data. 相似文献