全文获取类型
收费全文 | 170篇 |
免费 | 10篇 |
专业分类
化学 | 104篇 |
力学 | 4篇 |
数学 | 32篇 |
物理学 | 40篇 |
出版年
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 7篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1962年 | 2篇 |
1899年 | 1篇 |
1891年 | 1篇 |
排序方式: 共有180条查询结果,搜索用时 46 毫秒
91.
J R Johnstone V A Alder B M Johnstone D Robertson G K Yates 《The Journal of the Acoustical Society of America》1979,65(1):254-257
There is a close correlation between the sound pressure of tone burst required to affect a primary auditory neuron at its characteristic frequency and that which will produce a detectable N1 response at the same frequency. Units with thresholds from 80--0 db SPL (recorded from damaged and undamaged cochleas) were 0--20 dB , respectively, more sensitive than the action potential response. 相似文献
92.
Measurements of group delay were made extracellularly from spiral ganglion cells in the 3.7 to 5.0-mm region of the guinea pig cochlea, using sinusoidally amplitude modulated tones with constant modulating frequency (100 Hz) and depth of modulation (0.19). Threshold cochlear tuning was accompanied by frequency-dependent group delays. The group delay on the low-frequency tail was independent of carrier frequency; the interunit variation was 0.28-1.28 ms. The difference in group delay between CF and the low-frequency tail decreased as the CF threshold increased (-0.09 +/- 0.02 ms per 10 dB, beginning at 0.62 +/- 0.07 ms at 0 dB SPL). The group delay decreased above CF; at the units' maximum frequency it was less than the low-frequency tail value, and was sometimes negative. Following arterial injections of furosemide the CF threshold increased and the group delay peak decreased; the low-frequency tail was unaffected. The group delay decreased with increasing intensity; the reduction near and above CF was not only larger than that on the low-frequency tail, but also the change at 5-10 dB above threshold was far greater than expected from the Q10dB of the suprathreshold iso-rate tuning curves. A minimum-phase analysis suggested that the group delay response above CF, together with its nonlinear behavior, can be accounted for by a high-frequency, level-independent, amplitude plateau, in combination with the single unit, amplitude nonlinearity which is known to exist above CF. 相似文献
93.
94.
Mechanics of the guinea pig colea 总被引:1,自引:0,他引:1
B M Johnstone K J Taylor A J Boyle 《The Journal of the Acoustical Society of America》1970,47(2):504-509
95.
The five Raman-active phonons have been measured at low temperatures and for a range of x in the disordered lattice CsMg1-xCoxCl3. While the E2ga, E2gb, E2gc and A1g modes at 55.0, 132.0, 189.0 and 255.0 cm?1 for x = 0 exhibit normal one-mode behaviour, the intensity of the E1g phonon at 127.5 cm?1 has a most unusual concentration dependence which requires a new theory. 相似文献
96.
97.
98.
Johnstone KD Bampos N Sanders JK Gunter MJ 《Chemical communications (Cambridge, England)》2003,(12):1396-1397
The thermodynamically controlled self-assembly of a neutral donor-acceptor rotaxane, stoppered via porphyrin coordination and bound to polystyrene beads is described, and the dynamic equilibrium between solid and solution phases has been examined by HR MAS nmr spectroscopy. 相似文献
99.
A simple iterative procedure is illustrated here to overcome two problems frequently encountered in hot-wire anemometry: (1) the calibration of hot wires at low velocity and (2) to account for the wall-proximity correction in the actual measurements. The low-velocity calibration method used an iterative correction procedure based on laminar pipe velocity profiles. It is shown that the use of this approach, together with a simple wall proximity correction procedure, provides a simple and accurate calibration of both single and cross hot wires, and gives reliable measurements. 相似文献
100.
This paper is concerned with convex composite minimization problems in a Hilbert space. In these problems, the objective is the sum of two closed, proper, and convex functions where one is smooth and the other admits a computationally inexpensive proximal operator. We analyze a family of generalized inertial proximal splitting algorithms (GIPSA) for solving such problems. We establish weak convergence of the generated sequence when the minimum is attained. Our analysis unifies and extends several previous results. We then focus on \(\ell _1\)-regularized optimization, which is the ubiquitous special case where the nonsmooth term is the \(\ell _1\)-norm. For certain parameter choices, GIPSA is amenable to a local analysis for this problem. For these choices we show that GIPSA achieves finite “active manifold identification”, i.e. convergence in a finite number of iterations to the optimal support and sign, after which GIPSA reduces to minimizing a local smooth function. We prove local linear convergence under either restricted strong convexity or a strict complementarity condition. We determine the rate in terms of the inertia, stepsize, and local curvature. Our local analysis is applicable to certain recent variants of the Fast Iterative Shrinkage–Thresholding Algorithm (FISTA), for which we establish active manifold identification and local linear convergence. Based on our analysis we propose a momentum restart scheme in these FISTA variants to obtain the optimal local linear convergence rate while maintaining desirable global properties. 相似文献