全文获取类型
收费全文 | 42篇 |
免费 | 3篇 |
国内免费 | 6篇 |
专业分类
化学 | 21篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 8篇 |
物理学 | 18篇 |
出版年
2021年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 6篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2009年 | 2篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1973年 | 1篇 |
1948年 | 3篇 |
排序方式: 共有51条查询结果,搜索用时 17 毫秒
21.
WANG Yue BI Xiao-Jun CUI Shu-Wang DING Lin-Kai DAN Zeng-Luo-Bu DING Xiao-Hong FAN Chao FENG Cun-Feng FENG Zhao-Yang FENG Zhen-Yong GAO Xiao-Yu GENG Qing-Xi GUO Hong-Wei HE Hui-Hai HE Mao HU Hai-Bing HU Hong-Bo HUANG Qing JIA Huan-Yu LA Ba-Ci-Ren LE Gui-Ming LI Ai-Feng LI Jin-Yu LOU Yu-Qing LU Hong LU Sui-Ling MENG Xian-Ru MU Jun REN Jing-Ru TAN You-Heng WANG Bo WANG Hui WANG Yong-Gang WU Han-Rong XUE Liang YANG Xian-Chu YE Zong-Hai YU Guang-Ce YUAN Ai-Fang ZHANG Hui-Min ZHANG Ji-Long ZHANG Nai-Jian ZHANG Xue-Yao ZHANG Yong ZHANG Yi ZHA Xi-Sang-Zhu ZHOU Xun-Xiu YUAN Qiang 《中国物理C(英文版)》2008,32(11)
Using the data taken from Tibet Ⅱ High Density (HD) Array (1997 February--1999 September) and Tibet-Ⅲ array (1999 November--2005 November), our previous northern sky survey for TeV γ-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.0° to 60.0° in declination (Dec) range, no new TeV γ-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV T-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits. 相似文献
22.
Nonlinear interaction of low-frequency resonant and high-frequency nonresonant plasma oscillations in the presence of an external magnetic field is studied. In the case of Iongitudinal waves it is shown that the up-conversion of plasma oscillations' energy is possible in such a system. 相似文献
23.
Abstract This paper is devoted to investigate extinction and nonextinction conditions of the extended Beverton–Holt equation (BHE) for dynamics of populations in Ecology when potential discontinuities at sampling points are included in the model. The proposed model is described by means of four sequences of parameters. Two of them are the intrinsic growth rate and the carrying capacity sequences which are included in the basic BHE model. The other two ones, namely, the harvesting (i.e., the hunting or fishing quota) and the internal consumption (which can include positive and negative migrations in the considered population habitat) sequences are included to parameterize the model discontinuities. Such discontinuities are related to impulses in the corresponding continuous‐time logistic equation. The obtained results establish how the harvesting quota and/or the internal consumption has to be fixed to guarantee the population nonextinction or, eventually, its extinction. Finally, some controllability results related to the search of a carrying capacity sequence such that the solution of the proposed impulsive BHE tracks a reference one are obtained. 相似文献
24.
25.
We present the first observation of two-photon polarization interference structure in the second-order Glauber correlation function of two-photon light generated via type-II spontaneous parametric down-conversion. In order to obtain this result, two-photon light is transmitted through an optical fiber and the coincidence distribution is analyzed by means of the start-stop method. Beyond the experimental demonstration of an interesting effect in quantum optics, these results also have considerable relevance for quantum communications. 相似文献
26.
We study the implementation of a correlation measurement technique for the characterization of squeezed light. We show that the sign of the covariance coefficient revealed from the time-resolved correlation data allow us to distinguish among squeezed, coherent, and thermal states. In contrast to the traditional method of characterizing squeezed light, involving measurement of the variation of the difference photocurrent, the correlation measurement method allows one to eliminate the contribution of the electronic noise, which becomes a crucial issue in experiments with dim sources of squeezed light. 相似文献
27.
28.
29.
David R. Hunter Pavel N. Krivitsky Michael Schweinberger 《Journal of computational and graphical statistics》2013,22(4):856-882
We review the broad range of recent statistical work in social network models, with emphasis on computational aspects of these methods. Particular focus is applied to exponential-family random graph models (ERGM) and latent variable models for data on complete networks observed at a single time point, though we also briefly review many methods for incompletely observed networks and networks observed at multiple time points. Although we mention far more modeling techniques than we can possibly cover in depth, we provide numerous citations to current literature. We illustrate several of the methods on a small, well-known network dataset, Sampson's monks, providing code where possible so that these analyses may be duplicated. 相似文献
30.
铸造铝青铜合金Cu-14Al-4Fe-Mn的摩擦磨损性能 总被引:7,自引:1,他引:7
用往复式摩擦磨损试验机考察了新型高强度、高耐磨性铸造铝青铜合金Cu-14Al-4Fe-Mn(代号HSWAB)的摩擦磨损性能,利用形貌扫描电子显微镜观察分析了合金磨损表面形貌,探讨了其磨损机理.结果表明,HSWAB合金在干摩擦和油润滑条件下的摩擦磨损性能及磨损机理存在明显差异.在干摩擦条件下,合金中脱落的硬质点及氧化物等磨粒导致较为严重的磨粒磨损,摩擦系数高、磨损率大,主要磨损机理为磨粒磨损、粘着磨损、氧化磨损及疲劳磨损.在油润滑条件下,摩擦系数和磨损率均显著降低,疲劳磨损和氧化磨损受到抑制,主要磨损机理为磨粒磨损和粘着磨损.Cu-14Al-4Fe-Mn合金在油润滑条件下的摩擦系数低达0.08,磨损率低达3.7×10-6g/m,是一种优良的耐磨材料. 相似文献