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71.
巡航导弹红外辐射及大气衰减计算模型 总被引:4,自引:1,他引:4
对巡航导弹3个主要辐射源:蒙皮、尾喷管及羽流进行了深入分析,建立了巡航导弹红外辐射计算模型.此外,在红外辐射的大气传输理论基础上,综合考虑高度、倾斜及气象条件等各种因素,分析了大气衰减对红外辐射的影响,建立了大气透过率的理论模型与计算方法.最后,以某型号巡航导弹为例,利用此模型计算了3~5μm和8~12μm两个波段的红外辐射强度、大气光谱透过率和平均透过率,以及经过大气衰减后的红外辐射强度,并对计算结果进行了分析.结果表明,这是一种计算巡航导弹红外辐射的简单方法. 相似文献
72.
本文以大展弦比、后掠翼飞机和轴对称导弹为例,分别建立了弹性飞机和细长体弹性飞行器在大气紊流中飞行时的动力学模型。该模型考虑了非定常气动力的影响以及刚性运动和弹性变形模态之间的气动耦合作用,并给出了其状态空间方程的标准形式。 相似文献
73.
本文通过对现有沉浮模态各种近似解析解的分析比较,修正了经典解析法完全略去△a自由度的假设,计及了对此模态有相当影响的气动导数Cma和Cmq的作用,导出了沉浮模态二阶近似方程。算例结果证实,本方法具有较高精度,优于现有的几种近似解析解。 相似文献
74.
Stephen M. Pompea 《Space Science Reviews》1995,74(1-2):181-193
The performance of infrared and submillimeter systems can be severely degraded by stray light. Stray light includes off-axis radiation, system diffraction and scattering effects, and thermal self-emission. The purpose of this paper is to identify several keys to preventing system degradation due to stray radiation. The first key is to apply stray light design rules and analysis techniques early in the program before the design is finalized. A systems level analysis using stray light analysis software is often necessary in order to identify more subtle problems and to assess the magnitude of their effect on system performance. Another key is to address contamination control and the choice of surface coatings early in the program. The management of stray radiation issues is extremely cost-effective, if begun early in the program, and can reduce later schedule hardships. 相似文献
75.
G. Rottman 《Space Science Reviews》2006,125(1-4):39-51
The Sun’s electromagnetic radiation powers our solar system. In the case of the Earth it heats the lands and ocean, maintains
our atmosphere, generates clouds, and cycles water. For other planets and minor bodies, similar and appropriate physical processes
occur, also powered by the Sun. The Sun varies on all time scales and a precise knowledge of the Sun's irradiance and its
variation is essential to our understanding of environments and physical conditions throughout our solar system. Measurements
of solar irradiance and its variation can only be made from space, and almost thirty years of observation have now established
that the total solar irradiance (TSI) varies by only 0.1 to 0.3%, while certain portions of the solar spectrum, the ultraviolet
for example, vary by orders of magnitude more. This paper provides an overview of TSI observations and of spectral irradiance
observations from the ultraviolet to the near infrared. 相似文献
76.
Lanfang H. Levine Patricia A. Bisbee Jeffrey T. Richards Michele N. Birmele Ronald L. Prior Michele Perchonok Mike Dixon Neil C. Yorio Gary W. Stutte Raymond M. Wheeler 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(5):754-762
This study addresses whether reduced atmospheric pressure (hypobaria) affects the quality traits of radish grown under such environments. Radish (Raphanus sativus L. cv. Cherry Bomb Hybrid II) plants were grown hydroponically in specially designed hypobaric plant growth chambers at three atmospheric pressures; 33, 66, and 96 kPa (control). Oxygen and carbon dioxide partial pressures were maintained constant at 21 and 0.12 kPa, respectively. Plants were harvested at 21 days after planting, with aerial shoots and swollen hypocotyls (edible portion of the radish referred to as the “root” hereafter) separated immediately upon removal from the chambers. Samples were subsequently evaluated for their sensory characteristics (color, taste, overall appearance, and texture), taste-determining factors (glucosinolate and soluble carbohydrate content and myrosinase activity), proximate nutrients (protein, dietary fiber, and carbohydrate) and potential health benefit attributes (antioxidant capacity). In roots of control plants, concentrations of glucosinolate, total soluble sugar, and nitrate, as well as myrosinase activity and total antioxidant capacity (measured as ORACFL), were 2.9, 20, 5.1, 9.4, and 1.9 times greater than the amount in leaves, respectively. There was no significant difference in total antioxidant capacity, sensory characteristics, carbohydrate composition, or proximate nutrient content among the three pressure treatments. However, glucosinolate content in the root and nitrate concentration in the leaf declined as the atmospheric pressure decreased, suggesting perturbation to some nitrogen-related metabolism. 相似文献
77.
78.
Michael W. Liemohn Yingjuan Ma Rudy A. Frahm Xiaohua Fang Janet U. Kozyra Andrew F. Nagy J. David Winningham James R. Sharber Stas Barabash Rickard Lundin 《Space Science Reviews》2006,126(1-4):63-76
Atmospheric photoelectrons have been observed well above the ionosphere of Mars by the ASPERA-3 ELS instrument on Mars Express.
To systematically interpret these observations, field lines from two global MHD simulations were analyzed for connectivity
to the dayside ionosphere (allowing photoelectron escape). It is found that there is a hollow cylinder behind the planet from
1–2 R
M away from the Mars-Sun line that has a high probability of containing magnetic field lines with connectivity to the dayside
ionosphere. These results are in complete agreement with the ELS statistics. It is concluded that the high-altitude photoelectrons
are the result of direct magnetic connectivity to the dayside at the moment of the measurement, and no extra trapping or bouncing
mechanisms are needed to explain the data. 相似文献
79.
为了探究CF4/SF6反应气体及其含量对大气压等离子体的温度的影响规律,采用红外热像仪记录等离子体反应区域的温度.实验结果表明在系统输入功率为260W时,对于CF4气体,等离子体区域的温度随着CF4含量的增加先升高然后降低;对于SF6气体,等离子体区域的温度随着SF6含量的增加而逐渐降低;在相同条件下,反应气体为SF6... 相似文献
80.
介绍了总温传感器的设计原理,并将国内外各型号进行对比和评价,提出了某新型总温传感器设计改进的方案原理. 相似文献