全文获取类型
收费全文 | 159篇 |
免费 | 10篇 |
国内免费 | 7篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 2篇 |
地球物理 | 16篇 |
地质学 | 16篇 |
海洋学 | 2篇 |
天文学 | 126篇 |
综合类 | 11篇 |
自然地理 | 2篇 |
出版年
2015年 | 8篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 3篇 |
2011年 | 25篇 |
2010年 | 26篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 32篇 |
2003年 | 24篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 31 毫秒
111.
Li-Yan Zhang Yong-Liao Zou Jian-Zhong Liu Jian-Jun Liu Ji Shen Ling-Li Mu Xin Ren Wei-Bin Wen Chun-Lai Li National Astronomical Observatories Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2011,(6)
The main goal of the gamma-ray spectrometer(GRS) onboard Chang'E1(CE-1) is to acquire global maps of elemental abundances and their distributions on the moon,since such maps will significantly improve our understanding of lunar formation and evolution.To derive the elemental maps and enable research on lunar formation and evolution,raw data that are received directly from the spacecraft must be converted into time series corrected gamma-ray spectra.The data correction procedures for the CE-1 GRS time series... 相似文献
112.
113.
Yi-Nan Zhu Hong Wu Hai-Ning Li Chen Cao National Astronomical Observatories Chinese Academy of Sciences Beijing China of Sciences China Graduate University of Chinese Academy of Sciences Beijing China Institute of Space Science Physics Sh ong University at Weihai Sh ong 《中国天文和天体物理学报》2010,10(4)
We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey.We derived the formulae to calculate the stellar mass by using IRAC 3.6 μm and 4.5 μm luminosities.The massto-luminosity ratios of IRAC 3.6 μm and 4.5 μm luminosities are more sensitive to the star formation history of galaxies than to other factors,such as the intrinsic extinction,metallicity and star formation rate.To remove the effect of star formation history,we used g-r color to recalibrate the formulae and obtain a better result.Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae.Due to the emission from dust heated by the hottest young stars,luminous infrared galaxies present higher IRAC 4.5 μm luminosities compared to IRAC 3.6 μm luminosities.For most of type-Ⅱ AGNs,the nuclear activity cannot enhance 3.6 μm and 4.5 μm luminosities compared with normal galaxies.Star formation in our AGNhosting galaxies is also very weak,almost all of which are early-type galaxies. 相似文献
114.
Xu Zhou Zhen-Yu Wu Zhao-Ji Jiang Xiang-Qun Cui Long-Long Feng Xue-Fei Gong Jing-Yao Hu Qi-Sheng Li Gen-Rong Liu Jun Ma Jia-Li Wang Li-Fan Wang Jiang-Hua Wu Li-Rong Xia Jun Yan Xiang-Yan Yuan Feng-Xiang Zhai Ru Zhang Zhen-Xi Zhu National Astronomical Observatories Chinese Academy of Sciences Beijing China Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Nanjing China Purple Mo... 《中国天文和天体物理学报》2010,10(3)
115.
Wang-Ping Zhou Yi Zheng Wei Guo Li Yu Chang-Song Yang School of Information & Control Engineering Nanjing University of Information Science & Technology Nanjing China Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Chinese Academy of Sciences Nanjing 《中国天文和天体物理学报》2010,10(1)
Heavy disturbances caused mainly by wind and friction in the mount drive system greatly impair the pointing accuracy of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST).To overcome this negative effect,a third order Higher Order Sliding Mode (HOSM) controller is proposed.The key part of this approach is to design an appropriate observer which obtains the acceleration state.A nonlinear adaptive observer is proposed in which a novel polynomial model is applied to estimate the internal di... 相似文献
116.
制冷接收机是射电望远镜的核心设备,它是否正常工作直接决定望远镜观测的效果。制冷接收机的制冷温度和杜瓦真空度是反映接收机是否正常工作的最重要、最直接的指标之一。因此实现制冷接收机制冷温度和杜瓦真空度的远程实时监控,及时了解接收机是否正常工作对保证射电望远镜正常运行、提高观测效率有重要意义。为乌鲁木齐天文站25m射电望远镜1.3cm制冷接收机研制的一套基于单片机和以太网的数据采集和数据传输的远程监视系统,实现了制冷接收机制冷温度和杜瓦真空度的远程实时监控。该系统采用了美国ATMEL公司生产的8位单片机AVR ATmega16、Microchip Technology公司生产的ENC28J60以及MAXIM公司生产的MAX7219,实现对射电天文制冷接收机制冷温度和杜瓦真空度的数据采集,并利用以太网传输数据实现了远程实时监控接收机的制冷状态。阐述了以太网数据采集及远程监控电路的设计原理及其实现方法。该系统首次在国内大型射电望远镜上实现了对制冷接收机工作状态的远程实时监控,对于保证乌鲁木齐天文站25m射电望远镜1.3cm波段的观测效果有重要作用。 相似文献
117.
Shan-Jie Qian Xi-Zhen ZhangNational Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2004,4(1):37-50
The rapid polarization position angle swing of ~ 180?observed in QSO 1150+812 at 2cm by Kochenov and Gabuzda is quite a regular event. One interesting property of the event is that, during the time of the swing the polarized flux density remained almost constant. We suggest that such an event can be explained in terms of a relativistic thin shock propagating through a uniform helical magnetic field, giving rise to relativistic aberration effects as the transverse field component rotates. The model may also be applicable to other similar events in which variations in polarization are not accompanied by variations in total flux density. 相似文献
118.
Qing-Yao Liu Yu-Lan YangNational Astronomical Observatories Yunnan Observatory Chinese Academy of Sciences Kunming United Laboratory of Optical Astronomy Chinese Academy of Sciences 《中国天文和天体物理学报》2003,3(2):142-150
A theoretical model for explaining the O‘Connell effect of close binary stars is given based on the hypothesis that the circumstellar material of a binary system is captured by its components.The results inferred form the model suggest that late-type and /or short-period binaries can easily produce obvious O‘Connell effect and that the occurrence of O‘Connell effect has no relation with the type of binaries,These conclusions are in agreement with the observed results.The observed O‘Connell effects of six binary systems are examined by the model.For three W-subtype W UMa binaries(YY Eri,BX Per and SW Lac).the densities of the materials captured by the two components are assumed to be equal,and the calculated O‘Connell effect is found to be almost equal to the observed effect.For three A-subtype W UMa systems(CN And,FG Hya and AU Ser),the two densities are assumed to be different,and are calculated separately.The calculated O‘Connell effect turns out to agree better with the observed effect than that was formerly obtained. 相似文献
119.
120.
本文介绍LAMOST反射施密特改正板系统在风载下的变形及象质变化情况。文中建立了改正板系统的整体有限元模型 ,并计算分析了在技术要求规定的风载下的响应 ,计算结果表明反射施密特改正板支撑结构的设计是满足技术要求的 相似文献