全文获取类型
收费全文 | 83篇 |
免费 | 9篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 23篇 |
地球物理 | 24篇 |
地质学 | 12篇 |
天文学 | 25篇 |
综合类 | 6篇 |
自然地理 | 7篇 |
出版年
2024年 | 1篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2011年 | 8篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1992年 | 2篇 |
排序方式: 共有97条查询结果,搜索用时 31 毫秒
81.
针对昆明VLBI观测站终端设备(S3数据采集系统)的特殊性,设计在标准的终端控制计算机(Field System)上能够控制相应硬件设备的软件.S3数据采集系统包括SX接收机、中频分配器、视频转换器、时延计数器、噪声控制开关和气象数据自动采集仪.设计过程中,考虑到软件的可读性和可维护性,各种设备分别用相应的子函数来完成具体功能,各子函数由主程序调用.在完成程序安装后,经测试能与S3数据采集系统进行良好的通讯,达到控制各硬件设备的目的及满足实际测控工作的需要. 相似文献
82.
83.
P.T. Timbie G.S. Tucker P.A.R. Ade S. Ali E. Bierman E.F. Bunn C. Calderon A.C. Gault P.O. Hyland B.G. Keating J. Kim A. Korotkov S.S. Malu P. Mauskopf J.A. Murphy C. OSullivan L. Piccirillo B.D. Wandelt 《New Astronomy Reviews》2006,50(11-12):999
We provide an overview of a mission concept study underway for the Einstein Inflation Probe (EIP). Our study investigates the advantages and tradeoffs of using an interferometer (EPIC) for the mission. We also report on the status of the millimeter-wave bolometric interferometer (MBI), a ground-based pathfinder optimized for degree-scale CMB polarization measurements at 90 GHz. 相似文献
84.
This study is devoted to the first French determinations of absolute gravity in the Antarctic (Dumont-d'Urville, Terre Adélie) and Arctic (Ny-Alesund, Spitsbergen) polar regions. The measurements in Dumont-d'Urville were performed in 2000 with the help of the FG5#206 absolute gravimeter belonging to the French geodetic community since beginning 1997; they show a strong noise that causes an uncertainty close to 11 μGal in the determination of the mean gravity value, which will be compared, to a new determination planned for 2005. The Ny-Alesund measurements show on the contrary a noise that, although very variable in time, leads to a gravity determination of better than 5 μGal. The comparison of our value with a previous one two years before suggests a gravity decrease of about 4 μGal which is related to the vertical uplift measured by Very Large Baseline Interferometry (VLBI) at the same site. However, the uncertainty does not allow discriminating between height-to-gravity conversion factors originating from different models. To cite this article: J. Hinderer et al., C. R. Geoscience 334 (2002) 819–826. 相似文献
85.
In the case of high angular resolution techniques (speckle interferometry, long baseline Michelson interferometry), one has studied how varies the signal-to-noise ratio (SNR) in terms of the spectral bandwidth . For values of varying from 0 up to 100 nanometers, it is shown that the SNR, contrary to the predictions, has no maximum value. In addition, in the case of the high frequency approximation, the effects of a finite spatial-coherence outer scale, the influence of the turbulence model used and of the optical energy of the turbulence on the optimal spectral bandwidth have been analyzed and discussed. 相似文献
86.
87.
G. Herrera R. Toms J.M. Lopez-Sanchez J. Delgado J.J. Mallorqui S. Duque J. Mulas 《Engineering Geology》2007,90(3-4):148-159
The town of La Union (SE, Spain) is located within a metal mining area that has been exploited since the Roman period. This historic exploitation has left behind a high concentration of abandoned underground mining galleries. Currently, an industrial area is subsiding due to the collapse of one of these galleries in May 1998. In this paper, an advanced Differential Interferometry SAR (DInSAR) method called the Coherent Pixels Technique (CPT) has been used to study the subsidence phenomena for two time intervals, from January 1998 to December 2000, and from March 2003 to December 2004. DInSAR-derived deformation maps have enabled the detection and monitoring of different deformation processes that affect several locations within the study area. By comparing these results with the underground mining galleries map, a clear relationship between their presence and the subsidence has been proved. Deformation values retrieved with DInSAR between April 2003 and December 2004 have been compared with the topographical leveling network measurements performed in this same period, providing an absolute average difference of 0.7 cm with a standard deviation of 0.5 cm. Results obtained in the city of La Union have shown that the advanced DInSAR technique is able to provide very useful spatial and temporal deformation data for the measurement of small scale subsidence throughout short time periods. This technique has enabled the temporal evolution of the phenomena in the city of La Unión to be studied and understanding of subsidence to be expanded beyond the limits of a deployed topographical control network, in a more cost effective way than classical methods. 相似文献
88.
Scott K. Rowland Mary E. MacKay Harold Garbeil Peter J. Mouginis-Mark 《Bulletin of Volcanology》1999,61(1-2):1-14
We analyze digital topographic data collected in September 1993 over a ∼500-km2 portion of K*lauea Volcano, Hawai'i, by the C-band (5.6-cm wavelength) topographic synthetic aperture radar (TOPSAR) airborne
interferometric radar. Field surveys covering an ∼1-km2 area of the summit caldera and the distal end of an ∼8-m-thick 'a'* flow indicate that the 10-m spatial resolution TOPSAR
data have a vertical accuracy of 1–2 m over a variety of volcanic surfaces. After conversion to a common datum, TOPSAR data
agree favorably with a digital elevation model (DEM) produced by the U.S. Geological Survey (USGS), with the important exception
of the region of the ongoing eruption (which postdates the USGS DEM). This DEM comparison gives us confidence that subtracting
the USGS data from TOPSAR data will produce a reasonable estimate of the erupted volume as of September 1993. This subtraction
produces dense rock equivalent (DRE) volumes of 392, 439, and 90×106 m3 for the Pu'u '*'*, K*pa'ianah*, and episode 50–53 stages of the eruption, respectively. These are 124, 89, and 94% of the
volumes calculated by staff of the Hawaiian Volcano Observatory (HVO) but do not include lava of K*pa'ianah* and episodes
50–53 that flowed into the ocean and are thus invisible to TOPSAR. Accounting for this lava increases the TOPSAR volumes to
124, 159, and 129% of the HVO volumes. Including the ±2-m uncertainty derived from the field surveys produces TOPSAR-derived
volumes for the eruption as a whole that range between 81 and 125% of the USGS-derived values. The vesicularity- and ocean-corrected
TOPSAR volumes yield volumetric eruption rates of 4.5, 4.5, and 2.7 m3/s for the three stages of the eruption, which compare with HVO-derived values of 3.6, 2.8, and 2.1 m3/s, respectively. Our analysis shows that care must be taken when vertically registering the TOPSAR and USGS DEMs to a common
datum because C-band TOPSAR penetrates only partially into thick forest and therefore produces a DEM within the tree canopy,
whereas the USGS DEM is adjusted for vegetation.
Received: 28 April 1998 / Accepted: 1 February 1999 相似文献
89.
VLBI标准接口是近年来在VLBI技术中诞生的一个新概念,它旨在解决多年来各VLBI数据传输系统不兼容的问题.该文阐述了VLBI数据传输系统的发展历史,包括传统的记录/回放系统和新兴的网络数据传输两方面的内容;说明了VLBI标准接口的作用和意义;并分别介绍了VLBI标准接口规范3方面的内容:VLBI标准接口件规范(VSI-H)、VLBI标准接口软件规范(VSI-S)和VLBI标准接口网络规范(VSI-E). 相似文献
90.
G. D. Gwanmesia J. Liu G. Chen S. Kesson S. M. Rigden R. C. Liebermann 《Physics and Chemistry of Minerals》2000,27(7):445-452
Dense isotropic polycrystalline specimens of majorite-rich garnets (Py100, Py62Mj38, Py50Mj50, Py21Mj79 and Mj100) along the pyrope (Mg3Al2Si3O12 = Py100)-majorite (MgSiO3 = Mj100) join were fabricated in a 2000-ton uniaxial split-sphere anvil apparatus (USSA-2000) at pressures from 10 to 18.5 GPa and
temperatures from 1200 to 1850 °C, within their stability fields in runs of 2–4-h duration, using hot-pressing techniques
developed by Gwanmesia et al. (1993). These specimens are single-phased, fine-grained (≤5 mm), free of microcracks, and have
bulk densities greater than 99% of the corresponding single-crystal X-ray density. Elastic compressional (P) and shear (S) wave velocities were determined at room pressure and temperature for these polycrystalline garnet specimens by phase comparison
ultrasonic interferometry. For Mj100, the P and S wave velocities are within 1% of the Hashin-Shtrikman averages calculated from the single crystal elastic moduli measured
by Brillouin spectroscopy. Both the elastic bulk modulus (K) and the shear modulus (G) decrease continuously with increasing majorite content from pyrope garnet (Py100) to pure majorite garnet (Mj100). The compositional dependence of K and G are given by K = 172.3 (40) − 0.085X, and G = 91.6 (10) − 0.038X, where X = mol% majorite), respectively, indicating that substitution of Si for Mg and Al decreases both K and G by about 5% along the solid solution series.
Received: 25 March 1999 / Accepted: 12 July 1999 相似文献