全文获取类型
收费全文 | 297篇 |
免费 | 0篇 |
专业分类
化学 | 105篇 |
晶体学 | 3篇 |
力学 | 8篇 |
数学 | 57篇 |
物理学 | 124篇 |
出版年
2019年 | 2篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 9篇 |
2013年 | 16篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1930年 | 1篇 |
1914年 | 2篇 |
排序方式: 共有297条查询结果,搜索用时 15 毫秒
121.
Proposals have been made to utilise arrays of GaAs lasers in optical computer memories. For fast, random access to data the use of acousto-optical deflectors seems feasible. The number of lasers for use with each deflector is normally severely limited, because of the bandwidth limitation which is inherent in acousto-optic devices. This note describes a technique whereby the bandwidth limitation can be largely overcome, so that light from many lasers can be deflected by a single deflector. 相似文献
122.
It is shown that a distribution theory form for the electrostatics of point multipoles can be constructed, which reduces to the usual theory away from the position of the multipole, but in which the total electromagnetic self-energy is zero and the self-force density is zero. 相似文献
123.
124.
Smith JR McNeil RR Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Rowe J Stuart D Imlay R Kirk P Lim J Metcalf W Myung SS Cheng CP Gu P Li J Li YK Ye MH Zhu YC Abashian A Gotow K Hu KP Low EH Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Abe K Fujii Y Higashi Y Kim SK Kurihara Y Maki A Nozaki T Omori T Sagawa H Sakai Y Sugimoto Y Takaiwa Y Terada S Walker R Kajino F Perticone D Poling R Thomas T Ishi Y Miyano K Miyata H 《Physical review D: Particles and fields》1990,42(3):949-951
125.
John R. Jezorek Jiwang Tang Wendy L. Cook Ronald Obie Dajing Ji Jannell M. Rowe 《Analytica chimica acta》1994,290(3):303-315
Surface modification of several silica gels with a number of silanes was studied, as well as further reactions of the modified surfaces. Complete reaction of aminopropylsilane was easily achieved if surface silanols were in excess. Triethoxysilylpropyl-p-nitrobenzamide (TESPN) reacts with difficulty, and complete reaction occured only with long reaction time (at least 12h). The maximum coverage of 100-Å pore silica gel by TESPN was found to be about 1.7 μmol/m2, considerably less than the 3–4 /gmmol/m2 of available silanol sites, probably due to steric effects of the large silane. Even at this maximum coverage, further reaction of the modified silica with trimethylsilyl capping groups occured, with additional coverage of about 1.0 μmol/m2. The maximum amount of silylpropylamido-p-phenylazo-8-quinolinol that could be bound to silica gel was found to be about 1.0 μmol/m2, again probably limited by steric effects of the large 8-quinolinol (oxine) moiety. Virtually complete conversion of parent nitrobenzamide silica gel (NBSG) to 8-quinolinol silica gel (QSG) could be achieved if NBSG coverage was less than about 0.7 μmol/m2. QSG materials were found to have a 2 oxine to 1 copper(II) stoichiometry, even with surface coverages as low as 0.16 μmol/m2. 相似文献
126.
Michael D. Guiver Gilles P. Robertson Sheri Rowe Stephen Foley Yong Soo Kang Hyun Chae Park Jongok Won Hoai Nam Le Thi 《Journal of polymer science. Part A, Polymer chemistry》2001,39(13):2103-2124
We previously conducted a detailed study of gas‐transport and other properties of a series of silicon derivatives of Udel polysulfone (PSf) and Radel polyphenylsulfone; we now report the details of their preparation by the reaction of lithiated polymer intermediates with chlorosilylalkylaryl electrophiles. Ortho‐sulfone‐substituted polymers with pendant trimethylsilyl, dimethylphenylsilyl, and diphenylmethylsilyl and other groups were obtained by direct metalation followed by the reaction of the dilithiated intermediate with the appropriate silyl electrophile. In addition, the structural regularity and geometry of the dilithiated site was also exploited to introduce silicon into the main chain by the reaction of dichlorosilyl electrophiles, leading to the formation of a new tricyclic heteroatom ring. Ortho‐ether PSf derivatives were obtained from a dibrominated polymer via the lithiation of brominated polymer and reaction with a silyl electrophile. The degree of substitution of the silyl groups was 2.0 or less from dilithiated polymers and was dependent on the electrophile reactivity and reaction conditions. A detailed structural characterization of the polymers by NMR and IR spectroscopy is reported in addition to glass‐transition temperatures and thermal stabilities. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2103–2124, 2001 相似文献
127.
128.
129.
130.