全文获取类型
收费全文 | 87篇 |
免费 | 0篇 |
专业分类
化学 | 34篇 |
数学 | 7篇 |
物理学 | 46篇 |
出版年
2017年 | 1篇 |
2015年 | 1篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1941年 | 1篇 |
1934年 | 4篇 |
1933年 | 3篇 |
1932年 | 2篇 |
1931年 | 1篇 |
1918年 | 2篇 |
排序方式: 共有87条查询结果,搜索用时 15 毫秒
21.
22.
Kohlrausch Holborn M. Wien Siemens Halske Washburn Bell Schlesinger Curtis W. A. Taylor S. F. Acree Western Electric Company Leeds Northrup E. W. Washburn Parker H. Pfleiderer H. von Ubisch Wetham Hartley Barrett Pfeiffer C. A. Nowak L. Archbutt und R. Höber 《Fresenius' Journal of Analytical Chemistry》1918,57(6-7):314-326
Ohne Zusammenfassung 相似文献
23.
We observe the movement of water over time between pores of differing sizes in Castlegate sandstone. To achieve this, we perform an NMR transverse relaxation exchange experiment for several mixing times. The resulting data are converted to 2D T2 distributions using a 2D inverse Laplace transform (ILT). We show for the first time that quantitative analysis of ILT distributions enables one to extract characteristic times for different pores sizes. This information is potentially useful for permeability determination as well as better understanding of exchange between specific pore subpopulations. 相似文献
24.
Ohne Zusammenfassung 相似文献
25.
Washburn BR Diddams SA Newbury NR Nicholson JW Yan MF Jørgensen CG 《Optics letters》2004,29(3):250-252
A phase-locked frequency comb in the near infrared is demonstrated with a mode-locked, erbium-doped, fiber laser whose output is amplified and spectrally broadened in dispersion-flattened, highly nonlinear optical fiber to span from 1100 to >2200 nm. The supercontinuum output comprises a frequency comb with a spacing set by the laser repetition rate and an offset by the carrier-envelope offset frequency, which is detected with the standard f-to-2f heterodyne technique. The comb spacing and offset frequency are phase locked to a stable rf signal with a fiber stretcher in the laser cavity and by control of the pump laser power, respectively. This infrared comb permits frequency metrology experiments in the near infrared in a compact, fiber-laser-based system. 相似文献
26.
27.
Experiments on a sufficiently disordered two-dimensional (2D) electron system in silicon reveal a new and unexpected kind of metallic behavior, where the conductivity decreases as sigma(n(s),T) = sigma(n(s),T = 0)+A(n(s))T(2) (where n(s) is carrier density) to a nonzero value as temperature T-->0. In 2D, the existence of a metal with dsigma/dT>0 is very surprising. In addition, a novel type of a metal-insulator transition obtains, which is unlike any known quantum phase transition in 2D. 相似文献
28.
Williams PA Papadakis SJ Patel AM Falvo MR Washburn S Superfine R 《Physical review letters》2002,89(25):255502
We report on the characterization of torsional oscillators which use multiwalled carbon nanotubes as the spring elements. Through atomic-force-microscope force-distance measurements we are able to apply torsional strains to the nanotubes and measure their torsional spring constants, and estimate their effective shear moduli. The data show that the nanotubes are stiffened by repeated flexing. We speculate that changes in the intershell mechanical coupling are responsible for the stiffening. 相似文献
29.
The temperature dependence of conductivity sigma(T) of a two-dimensional electron system in silicon has been studied in parallel magnetic fields B. At B = 0, the system displays a metal-insulator transition at a critical electron density n(c)(0), and dsigma/dT>0 in the metallic phase. At low fields ( B < or approximately equal to 2 T), n(c) increases as n(c)(B)-n(c)(0) proportional, variant Bbeta ( beta approximately 1), and the zero-temperature conductivity scales as sigma(n(s),B,T = 0)/sigma(n(s),0,0) = f(B(beta)/delta(n)), where delta(n) = [n(s)-n(c)(0)]/n(c)(0) and n(s) is electron density, as expected for a quantum phase transition. The metallic phase persists in fields of up to 18 T, consistent with the saturation of n(c) at high fields. 相似文献
30.
A. R. Washburn 《Journal of Optimization Theory and Applications》1995,85(3):705-726
The problem considered is as follows:m resources are to be allocated ton activities, with resourcei contributing linearly to the potential for activityj according to the coefficientE(i,j). The objective is to minimize some nonlinear function of the potentials. If the objective function is sufficiently well behaved, the problem can be solved in finitely many steps using the method described in this paper.The author thanks S. Toi Lawphongpanich for several helpful references and suggestions. 相似文献