全文获取类型
收费全文 | 230篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
航空 | 117篇 |
航天技术 | 59篇 |
航天 | 57篇 |
出版年
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 10篇 |
2011年 | 21篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 14篇 |
2007年 | 15篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 1篇 |
排序方式: 共有233条查询结果,搜索用时 31 毫秒
181.
The Mercury Dual Imaging System on the MESSENGER Spacecraft 总被引:1,自引:0,他引:1
S. Edward Hawkins III John D. Boldt Edward H. Darlington Raymond Espiritu Robert E. Gold Bruce Gotwols Matthew P. Grey Christopher D. Hash John R. Hayes Steven E. Jaskulek Charles J. Kardian Jr. Mary R. Keller Erick R. Malaret Scott L. Murchie Patricia K. Murphy Keith Peacock Louise M. Prockter R. Alan Reiter Mark S. Robinson Edward D. Schaefer Richard G. Shelton Raymond E. Sterner II Howard W. Taylor Thomas R. Watters Bruce D. Williams 《Space Science Reviews》2007,131(1-4):247-338
The Mercury Dual Imaging System (MDIS) on the MESSENGER spacecraft will provide critical measurements tracing Mercury’s origin
and evolution. MDIS consists of a monochrome narrow-angle camera (NAC) and a multispectral wide-angle camera (WAC). The NAC
is a 1.5° field-of-view (FOV) off-axis reflector, coaligned with the WAC, a four-element refractor with a 10.5° FOV and 12-color
filter wheel. The focal plane electronics of each camera are identical and use a 1,024×1,024 Atmel (Thomson) TH7888A charge-coupled
device detector. Only one camera operates at a time, allowing them to share a common set of control electronics. The NAC and
the WAC are mounted on a pivoting platform that provides a 90° field-of-regard, extending 40° sunward and 50° anti-sunward
from the spacecraft +Z-axis—the boresight direction of most of MESSENGER’s instruments. Onboard data compression provides capabilities for pixel
binning, remapping of 12-bit data into 8 bits, and lossless or lossy compression. MDIS will acquire four main data sets at
Mercury during three flybys and the two-Mercury-solar-day nominal mission: a monochrome global image mosaic at near-zero emission
angles and moderate incidence angles, a stereo-complement map at off-nadir geometry and near-identical lighting, multicolor
images at low incidence angles, and targeted high-resolution images of key surface features. These data will be used to construct
a global image base map, a digital terrain model, global maps of color properties, and mosaics of high-resolution image strips.
Analysis of these data will provide information on Mercury’s impact history, tectonic processes, the composition and emplacement
history of volcanic materials, and the thickness distribution and compositional variations of crustal materials. This paper
summarizes MDIS’s science objectives and technical design, including the common payload design of the MDIS data processing
units, as well as detailed results from ground and early flight calibrations and plans for Mercury image products to be generated
from MDIS data. 相似文献
182.
Satellites have been rightly described as the lifeblood of the entire space industry and the number of satellites ordered or launched per year is an important defining metric of the industry's level of activity, such that trends and variability in this volume have significant strategic impact on the space industry. Over the past 40+ years, hundreds of satellites have been launched every year. Thus an important dataset is available for time series analysis and identification of trends and cycles in the various markets of the space industry. This article reports findings of a study for which we collected data on over 6000 satellites launched since 1960 on a yearly basis. We grouped the satellites into three broad categories – defense and intelligence, science, and commercial satellites – and identified and discussed the main trends and cyclical patterns for each of these. Institutional customers (defense and intelligence, and science) accounted for over two-thirds of all satellites launched within our time period (1960–2008), and, in the 1960s and 1970s, they accounted for 90% and 73.5%, respectively. A fair conclusion from this data is that the space industry was enabled by, and grew because of the institutional customers, not commercial market forces. However, when the launch data is examined more closely, a growing influence of the commercial sector is noticeable. Over the past two decades communication satellites accounted for roughly half of all launches, thus reflecting an important shift in the space industry in which the commercial sector is playing an equal role (on a launch volume basis) to that of the institutional market. Cyclical patterns in the satellite launch volume over the past decade are separately discussed before we sum up with a conclusion. 相似文献
183.
Andrew W. Stephan Eric J. Korpela Martin M. Sirk Scott L. England Thomas J. Immel 《Space Science Reviews》2017,212(1-2):645-654
The NASA Ionospheric Connection Explorer Extreme Ultraviolet spectrograph, ICON EUV, will measure altitude profiles of the daytime extreme-ultraviolet (EUV) OII emission near 83.4 and 61.7 nm that are used to determine density profiles and state parameters of the ionosphere. This paper describes the algorithm concept and approach to inverting these measured OII emission profiles to derive the associated \(\mathrm{O}^{+}\) density profile from 150–450 km as a proxy for the electron content in the F-region of the ionosphere. The algorithm incorporates a bias evaluation and feedback step, developed at the U.S. Naval Research Laboratory using data from the Special Sensor Ultraviolet Limb Imager (SSULI) and the Remote Atmospheric and Ionospheric Detection System (RAIDS) missions, that is able to effectively mitigate the effects of systematic instrument calibration errors and inaccuracies in the original photon source within the forward model. Results are presented from end-to-end simulations that convolved simulated airglow profiles with the expected instrument measurement response to produce profiles that were inverted with the algorithm to return data products for comparison to truth. Simulations of measurements over a representative ICON orbit show the algorithm is able to reproduce hmF2 values to better than 5 km accuracy, and NmF2 to better than 12% accuracy over a 12-second integration, and demonstrate that the ICON EUV instrument and daytime ionosphere algorithm can meet the ICON science objectives which require 20 km vertical resolution in hmF2 and 18% precision in NmF2. 相似文献
184.
Panning Mark P. Lognonné Philippe Bruce Banerdt W. Garcia Raphaël Golombek Matthew Kedar Sharon Knapmeyer-Endrun Brigitte Mocquet Antoine Teanby Nick A. Tromp Jeroen Weber Renee Beucler Eric Blanchette-Guertin Jean-Francois Bozdağ Ebru Drilleau Mélanie Gudkova Tamara Hempel Stefanie Khan Amir Lekić Vedran Murdoch Naomi Plesa Ana-Catalina Rivoldini Atillio Schmerr Nicholas Ruan Youyi Verhoeven Olivier Gao Chao Christensen Ulrich Clinton John Dehant Veronique Giardini Domenico Mimoun David Thomas Pike W. Smrekar Sue Wieczorek Mark Knapmeyer Martin Wookey James 《Space Science Reviews》2017,211(1-4):611-650
Space Science Reviews - The InSight lander will deliver geophysical instruments to Mars in 2018, including seismometers installed directly on the surface (Seismic Experiment for Interior Structure,... 相似文献
185.
T. M. Ho N. Thomas D. C. Boice C. Kollein L. A. Soderblom 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2003,31(12):2583-2589
Images obtained by the Miniature Integrated Camera and Imaging Spectrometer (MICAS) experiment onboard the Deep Space 1 spacecraft which encountered comet 19P/Borrelly on September 22nd 2001 show a dust coma dominated by jets. In particular a major collimated dust jet on the sunward side of the nucleus was observed. Our approach to analyse these features is to integrate the observed intensity in concentric envelopes around the nucleus. The same procedures has been used on the Halley Multicolour Camera images of comet 1P/Halley acquired on March 14th 1986. We are able to show that at Borrelly the dust brightness dependence as a function of radial distance is different to that of Halley. At large distances both comets show constant values as the size of the concentric envelopes increases (as one would expect for force free radial outflow). For Halley the integral decreases as one gets closer to the nucleus. Borrelly shows opposite behaviour. The main cause for Halley's intensity distribution is either high optical thickness or particle fragmentation. For Borrelly, we have constructed a simple model of the brightness distribution near the nucleus. This indicates that the influence of deviations from point source geometry is insufficient to explain the observed steepening of the intensity profile close to the nucleus. Dust acceleration or fragmentation into submicron particles appear to be required. We also estimate the dust production rate of Borrelly with respect to Halley and compare their dust to gas ratios. 相似文献
186.
An instrument for advanced studies of the solar corona is described. Its optical system provides nearly stigmatic imaging of selected portions of the Sun over the spectral range from 22.5 to 44.0 nm. Both spectroheliograms and emission line profiles of coronal features will be obtained over a wide range of coronal temperatures.Proceedings of the Conference Solar Physics from Space, held at the Swiss Federal Institute of Technology Zurich (ETHZ), 11–14 November 1980.This paper was presented at the conference by U. Feldman. 相似文献
187.
G. Cremonese A. Sprague J. Warell N. Thomas L. Ksamfomality 《Space Science Reviews》2007,132(2-4):291-306
The Mariner 10 spacecraft made three flyby passes of Mercury in 1974 and 1975. It imaged a little less than half of the surface
and discovered Mercury had an intrinsic magnetic field. This paper briefly describes the surface of Mercury as seen by Mariner
10 as a backdrop to the discoveries made since then by ground-based observations and the optimistic anticipation of new discoveries
by MESSENGER and BepiColombo spacecraft that are scheduled for encounter in the next decade. 相似文献
188.
Thomas H. Zurbuchen 《Space Science Reviews》2007,130(1-4):515-526
The extraordinary life and scientific achievements of Johannes Geiss span an almost impossible breadth of scientific topics,
from the study of rocks to tenuous plasmas, from volcanoes to meteorites. But, his impact also extends way beyond the field
of science. Professor Geiss is a well-known teacher and a highly successful science leader whose impact has been felt at the
University of Bern, in Switzerland, and around the globe. We present here a brief summary of this highly successful career
via a pictorial overview and a movie compiled by a former student who had the good luck to work with Professor Geiss during
his years at the University of Bern.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
189.
The Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) on the New Horizons Mission
Ralph L. McNutt Jr. Stefano A. Livi Reid S. Gurnee Matthew E. Hill Kim A. Cooper G. Bruce Andrews Edwin P. Keath Stamatios M. Krimigis Donald G. Mitchell Barry Tossman Fran Bagenal John D. Boldt Walter Bradley William S. Devereux George C. Ho Stephen E. Jaskulek Thomas W. LeFevere Horace Malcom Geoffrey A. Marcus John R. Hayes G. Ty Moore Nikolaos P. Paschalidis Mark E. Perry Bruce D. Williams Paul Wilson IV Lawrence E. Brown Martha B. Kusterer Jon D. Vandegriff 《Space Science Reviews》2009,145(3-4):381-381
190.
Daniel B. Reisenfeld Roger C. Wiens Bruce L. Barraclough John T. Steinberg Marcia Neugebauer Jim Raines Thomas H. Zurbuchen 《Space Science Reviews》2013,175(1-4):125-164
We describe the Genesis mission solar-wind sample collection period and the solar wind conditions at the L1 point during this 2.3-year period. In order to relate the solar wind samples to solar composition, the conditions under which the samples were collected must be understood in the context of the long-term solar wind. We find that the state of the solar wind was typical of conditions over the past four solar cycles. However, Genesis spent a relatively large fraction of the time in coronal-hole flow as compared to what might have been expected for the declining phase of the solar cycle. Data from the Solar Wind Ion Composition Spectrometer (SWICS) on the Advanced Composition Explorer (ACE) are used to determine the effectiveness of the Genesis solar-wind regime selection algorithm. The data collected by SWICS confirm that the Genesis algorithm successfully separated and collected solar wind regimes having distinct solar origins, particularly in the case of the coronal hole sample. The SWICS data also demonstrate that the different regimes are elementally fractionated. When compared with Ulysses composition data from the previous solar cycle, we find a similar degree of fractionation between regimes as well as fractionation relative to the average photospheric composition. The Genesis solar wind samples are under long-term curation at NASA Johnson Space Center so that as sample analysis techniques evolve, pristine solar wind samples will be available to the scientific community in the decades to come. This article and a companion paper (Wiens et al. 2013, this issue) provide post-flight information necessary for the analysis of the Genesis array and foil solar wind samples and the Genesis solar wind ion concentrator samples, and thus serve to complement the Space Science Review volume, The Genesis Mission (v. 105, 2003). 相似文献