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901.
I. F. Clarke 《Space Policy》1991,7(4):328-331
During the last 40 years — the merest blip in world history — talk about Homo astronauticus has signalled a growing awareness that the passengers on planet Earth can, if they want, take off for other destinations. If the scale of past advances is a satisfactory measure of future possibilities, then the wish will be father of the achievement.  相似文献   
902.
Qualitative Reasoning (QR) is a branch of Artificial Intelligence that arose from research on engineering problem solving. This paper describes the major QR methods and techniques, which, we believe, are capable of addressing some of the problems that are emphasized in the literature and posed by CELSS modeling, simulation, and control at the supervisory level.  相似文献   
903.
Pilot experiments developed in Los Andes Range, Central Zone of Chile, have obtained significant snd positive preliminary results on the use of multispectral and multitemporal satellite images to prepare snowmelt runoff forecasts by measuring snowcovered area in Andean watersheds. The same information is also very useful for studying regional and semi-regional geothermal activity along Los Andes in Chile. These results will be improved with the new satellite data to be available in the next years.  相似文献   
904.
905.
906.
Deutsche Aerospace Airbus (division of DASA) and Rosemount Aerospace Inc. Jointly sponsored a flight test program to evaluate in-flight performance of distributed multifunction air data smart probes. The probes measure pitot pressure, static pressure, and angle of attack. The tests were conducted at the DLR Flight Test Center, near Braunschweig, Germany. Two smart probes were installed on the DLR VFW 614 ATTAS Flight Test Aircraft and tested between June of 1992 and January of 1993. Flight test results are presented together with suggested air data system architectures, including ARINC 738, that can be used with the distributed smart probe concept. New architectures are developed for future commercial aircraft. The smart probe concept offers several advantages including reduced weight and size, reduced number of line replaceable units (LRUs), and increased reliability. Overall cost of ownership is significantly lowered  相似文献   
907.
The European Space Agency's studies of a Comet Nucleus Sample Return mission (ROSETTA) as its Planetary Cornerstone in its long-term programme 'Horizon 2000' and the Marsnet mission, a potential contribution of the Agency to an international network of surface stations on Mars, has revived the interest in the present state of Planetary Protection requirements. MARSNET was one of the four candidate missions selected in April 1991 for further Design Feasibility (Phase A) Studies. Furthermore, of all space agencies participating in planetary exploration activities only the United States National Aeronautics and Space Administration had a well established Planetary Protection Policy on Viking and other relevant planetary missions, whereas ESA is considering the feasibility and potential impact of a planetary protection policy on its Marsnet mission, within the framework of a tight budgetary envelope applicable to ESA's medium (M) class missions. This paper will discuss in general terms the impact of Planetary Protection measures, its implications for Marsnet and the issues arising from this for the implementation of the mission in ESA's scientific programme.  相似文献   
908.
With the evaporation of funding support for the National Aero Space Plane (NASP), realization of a single stage to orbit night system has been deferred. With the resource down sizing of the NASP management and technical team, development of the NASP concept appears to be delayed beyond the year 2030. To fill this gap for shorter flight times to remote destinations over 8,000 km, it is now proposed to convert the existing NASA shuttle to a passenger configuration and air launch horizontally from a Boeing 747 aircraft as the first stage carrier after climb to launch altitude. This US Shuttle concept may permit the transport of 100 passengers to destinations 10,000 km distant during a flight duration of 90 minutes, and during flight durations of about 120 minutes to any commercial destination on the planet Earth. This long distance system takes advantage of the existing shuttle and Boeing 747 airframe and propulsion technology, and can be implemented within the next decade  相似文献   
909.
ALTEA-MICE will supplement the ALTEA project on astronauts and provide information on the functional visual impairment possibly induced by heavy ions during prolonged operations in microgravity. Goals of ALTEA-MICE are: (1) to investigate the effects of heavy ions on the visual system of normal and mutant mice with retinal defects; (2) to define reliable experimental conditions for space research; and (3) to develop animal models to study the physiological consequences of space travels on humans. Remotely controlled mouse setup, applied electrophysiological recording methods, remote particle monitoring, and experimental procedures were developed and tested. The project has proved feasible under laboratory-controlled conditions comparable in important aspects to those of astronauts' exposure to particle in space. Experiments are performed at the Brookhaven National Laboratories [BNL] (Upton, NY, USA) and the Gesellschaft für Schwerionenforschung mbH [GSI]/Biophysik (Darmstadt, FRG) to identify possible electrophysiological changes and/or activation of protective mechanisms in response to pulsed radiation. Offline data analyses are in progress and observations are still anecdotal. Electrophysiological changes after pulsed radiation are within the limits of spontaneous variability under anesthesia, with only indirect evidence of possible retinal/cortical responses. Immunostaining showed changes (e.g. increased expression of FGF2 protein in the outer nuclear layer) suggesting a retinal stress reaction to high-energy particles of potential relevance in space.  相似文献   
910.
Organic chemistry on Titan and prebiotic chemistry on Earth involve the same N-containing organics: nitriles and their oligomers. Couplings of their chemistry in the three parts of Titan's geofluid (atmosphere, aerosols and surface) seem to play a key role in the organic chemical evolution of the planet. If liquid water was present on Titan, then a prebiotic chemistry, involving eutectics, similar to that of the early Earth, may have occurred. However, liquid water is currently absent and a prebiotic chemistry based only on N-organics may be evolving now on Titan. The other consequence of the low temperatures of Titan is the possible formation of organics unstable at room temperature and very reactive. So far, these compounds have not been systematically searched for in experimental studies of Titan's organic chemistry. C4N2 has already been detected on Titan. Powerful reactants in organic chemistry, CH2N2, and CH3N3, may be also present. They exhibit spectral signatures in the mid-IR strong enough to allow their detection at the 10-100 ppb level. They may be detectable on future IR spectra (ISO and Cassini) of Titan.  相似文献   
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