全文获取类型
收费全文 | 334篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
化学 | 228篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 44篇 |
物理学 | 73篇 |
出版年
2022年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 14篇 |
2013年 | 9篇 |
2012年 | 19篇 |
2011年 | 23篇 |
2010年 | 11篇 |
2009年 | 17篇 |
2008年 | 16篇 |
2007年 | 17篇 |
2006年 | 21篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1938年 | 2篇 |
1933年 | 3篇 |
1928年 | 3篇 |
1924年 | 2篇 |
1911年 | 2篇 |
1882年 | 2篇 |
1880年 | 3篇 |
1871年 | 2篇 |
排序方式: 共有349条查询结果,搜索用时 15 毫秒
1.
2.
3.
Arno Jüschke Johannes Jahn Andreas Kirsch 《Computational Optimization and Applications》1997,7(3):261-276
In this paper we consider a special optimization problem withtwo objectives which arises in antenna theory. It is shown that thisabstract bicriterial optimization problem has at least one solution.Discretized versions of this problem are also discussed, and therelationships between these finite dimensional problems and the infinitedimensional problem are investigated. Moreover, we presentnumerical results for special parameters using a multiobjectiveoptimization method. 相似文献
4.
Editor's preface 总被引:1,自引:0,他引:1
Johannes Jahn 《Mathematical Methods of Operations Research》1991,35(3):I-I
5.
Contingent epiderivatives and set-valued optimization 总被引:24,自引:0,他引:24
In this paper we introduce the concept of the contingent epiderivative for a set-valued map which modifies a notion introduced by Aubin [2] as upper contingent derivative. It is shown that this kind of a derivative has important properties and is one possible generalization of directional derivatives in the single-valued convex case. For optimization problems with a set-valued objective function optimality conditions based on the concept of the contingent epiderivative are proved which are necessary and sufficient under suitable assumptions. 相似文献
6.
Jahn A Vreeland WN Gaitan M Locascio LE 《Journal of the American Chemical Society》2004,126(9):2674-2675
Traditional liposome preparation methods are based on mixing of bulk phases, leading to inhomogeneous chemical and/or mechanical conditions during formation; hence liposomes are often polydisperse in size and lamellarity. Here we show the formation of liposomes that encapsulate reagents in a continuous two-phase flow microfluidic network with precision control of size from 100 to 300 nm by manipulation of liquid flow rates. We demonstrate that by creating a solvent-aqueous interfacial region in a microfluidic format that is homogeneous and controllable on the length scale of a liposome, we can facilitate the fine control of liposome size and polydispersity. 相似文献
7.
J. Maštovský J. Blaha L. Rothhardt G. Jahn H. Kneipp 《Czechoslovak Journal of Physics》1976,26(8):860-862
The limitation of the applicability of plasma eaters in mixtures of argon with molecular components is shown. We were able to measuren
e
andT
e
in argon-hydrogen mixture behind the reflected shock wave and find a strong reduction of both parameters caused by the molecular species. Similarly, the delay of the onset of ionization in argon-hydrogen and argon-nitrogen mixtures is substantially reduced. On the other hand, the molecular component reduces the velocity of thermodynamic equilibration, as has been shown by means of time resolved optical interferometry. 相似文献
8.
F. zu Bentheim P. David J. Debrus F. Hinterberger R. Jahn F. Lübke H. Mommsen R. Schoenmackers B. Schüller 《Zeitschrift für Physik A Hadrons and Nuclei》1976,40(3):163-168
Experimental data of the elastic scattering of-particles on10B forE
= 30–50.6 MeV are presented. They are analysed together with the data of a previous measurement forE
= 5–30 MeV in the frame of the optical model including spin-orbit coupling. The interaction radii of the-10B-systems are determined with the Inopin-Ericson model forE
= 5–50 MeV. The mean free path of-particles in10B is calculated. 相似文献
9.
Jan Zelenka Dr. Aleksandr Pereverzev Dr. Ullrich Jahn Prof. Dr. Jana Roithová 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(28):e202104493
Photocatalytic generation of nitrenes and radicals can be used to tune or even control their reactivity. Photocatalytic activation of sulfonyl azides leads to the elimination of N2 and the resulting reactive species initiate C−H activations and amide formation reactions. Here, we present reactive radicals that are generated from sulfonyl azides: sulfonyl nitrene radical anion, sulfonyl nitrene and sulfonyl amidyl radical, and test their gas phase reactivity in C−H activation reactions. The sulfonyl nitrene radical anion is the least reactive and its reactivity is governed by the proton coupled electron transfer mechanism. In contrast, sulfonyl nitrene and sulfonyl amidyl radicals react via hydrogen atom transfer pathways. These reactivities and detailed characterization of the radicals with vibrational spectroscopy and with DFT calculations provide information necessary for taking control over the reactivity of these intermediates. 相似文献
10.