全文获取类型
收费全文 | 221篇 |
免费 | 0篇 |
专业分类
化学 | 70篇 |
力学 | 1篇 |
数学 | 29篇 |
物理学 | 121篇 |
出版年
2017年 | 3篇 |
2016年 | 2篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 12篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1969年 | 2篇 |
1968年 | 4篇 |
1967年 | 3篇 |
1966年 | 1篇 |
1965年 | 4篇 |
排序方式: 共有221条查询结果,搜索用时 15 毫秒
91.
George S. Fishman 《Journal of computational and graphical statistics》2013,22(3):713-738
This article describes a multistage Markov chain Monte Carlo (MSMCMC) procedure for estimating the count, , where denotes the set of all a × b contingency tables with specified row and column sums and m total entries. On each stage s = 1, …, r, Hastings–Metropolis (HM) sampling generates states with equilibrium distribution , with inverse-temperature schedule β1 = 0 < β2 < ??? < β r < β r + 1 = ∞; nonnegative penalty function H, with global minima H(x) = 0 only for ; and superset , which facilitates sampling by relaxing column sums while maintaining row sums. Two kernels are employed for nominating states. For small β s , one admits moderate-to-large penalty changes. For large β s , the other allows only small changes. Neither kernel admits local minima, thus avoiding an impediment to convergence. Preliminary sampling determines when to switch from one kernel to the other to minimize relative error. Cycling through stages in the order r to 1, rather than 1 to r, speeds convergence for large β s . A comparison of estimates for examples, whose dimensions range from 15 to 24, with exact counts based on Barvinok’s algorithm and estimates based on sequential importance sampling (SIS) favors these alternatives. However, the comparison strongly favors MSMCMC for an example with 64 dimensions. It estimated count with 3.3354 × 10? 3 relative error, whereas the exact counting method was unable to produce a result in more than 182 CPU (computational) days of execution, and SIS would have required at least 42 times as much CPU time to generate an estimate with the same relative error. This latter comparison confirms the known limitations of exact counting methods and of SIS for larger-dimensional problems and suggests that MSMCMC may be a suitable alternative. Proofs not given in the article appear in the Appendix in the online supplemental materials. 相似文献
92.
Buchleitner A d'Arcy MB Fishman S Gardiner SA Guarneri I Ma ZY Rebuzzini L Summy GS 《Physical review letters》2006,96(16):164101
We show that mode locking finds a purely quantum nondissipative counterpart in atom-optical quantum accelerator modes. These modes are formed by exposing cold atoms to periodic kicks in the direction of the gravitational field. They are anchored to generalized Arnol'd tongues, parameter regions where driven nonlinear classical systems exhibit mode locking. A hierarchy for the rational numbers known as the Farey tree provides an ordering of the Arnol'd tongues and hence of experimentally observed accelerator modes. 相似文献
93.
K. L. Shukhina A. I. Fishman S. S. Kharintsev A. I. Skvortzov 《Bulletin of the Lebedev Physics Institute》2018,45(3):95-98
Photoinduced dichroism (PD) in azo-containing polymers can result from chromophore orientation and/or cis-isomer accumulation. The PD formation mechanism of azochrommophores DO3 (DisperseOrange 3) doped in polymethyl methacrylate (PMMA) at a temperature varying from –20 to +120 °C is studied by UV-visible spectroscopy. It is shown that the main PD formation mechanism at T < 0°C and T > 60°C is cis-isomer accumulation and trans-isomer photoorientation, respectively. 相似文献
94.
95.
96.
Il Nuovo Cimento D - We calculated the energy and the wave function of the exciton for i) a V-shaped quantum wire, ii) a T-shaped quantum wire and iii) a quantum wire resulting from strain-induced... 相似文献
97.
98.
99.
NMR spectra of estrogen catechols 总被引:2,自引:0,他引:2
100.
Pyridoxylated hemoglobin derivatives have been studied by many investigators. In this study hemoglobin A0 rather than stroma-free hemoglobin was used as a starting material in order to reduce the number of proteins to A0 and A1c. Derivatives were characterized using a Synchropak Q300 strong anion-exchange column, a PolyCAT A weak cation-exchange column and a VYDAC reversed-phase high-performance liquid chromatographic column. Resulting peak profiles of these two ion-exchange separations demonstrated enhanced resolution and showed the presence of pyridoxylated hemoglobin products not previously described. We compared products from the reduction of these Schiff base derivatives using either sodium borohydride or sodium cyanoborohydride reduction procedures. The sodium cyanoborohydride reduction method produced a lower percentage of products with multiple-site pyridoxylation modifications than the sodium borohydride reduction process. 相似文献