首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3392篇
  免费   4篇
  国内免费   3篇
航空   1903篇
航天技术   827篇
综合类   13篇
航天   656篇
  2018年   186篇
  2017年   155篇
  2016年   51篇
  2015年   33篇
  2014年   25篇
  2013年   50篇
  2012年   69篇
  2011年   193篇
  2010年   178篇
  2009年   187篇
  2008年   219篇
  2007年   179篇
  2006年   33篇
  2005年   101篇
  2004年   84篇
  2003年   72篇
  2002年   37篇
  2001年   60篇
  2000年   49篇
  1999年   27篇
  1998年   76篇
  1997年   53篇
  1996年   62篇
  1995年   69篇
  1994年   85篇
  1993年   56篇
  1992年   71篇
  1991年   29篇
  1990年   33篇
  1989年   70篇
  1988年   24篇
  1987年   29篇
  1986年   50篇
  1985年   87篇
  1984年   54篇
  1983年   60篇
  1982年   56篇
  1981年   68篇
  1980年   34篇
  1979年   27篇
  1978年   25篇
  1977年   24篇
  1975年   24篇
  1974年   24篇
  1973年   24篇
  1972年   21篇
  1971年   31篇
  1969年   25篇
  1967年   20篇
  1966年   19篇
排序方式: 共有3399条查询结果,搜索用时 78 毫秒
251.
In the 1990s, based on detailed studies of the structure of active regions (AR), the concept of the magnetosphere of the active region was proposed. This includes almost all known structures presented in the active region, ranging from the radio granulation up to noise storms, the radiation of which manifests on the radio waves. The magnetosphere concept, which, from a common point of view, considers the manifestations of the radio emission of the active region as a single active complex, allows one to shed light on the relation between stable and active processes and their interrelations. It is especially important to identify the basic ways of transforming nonthermal energy into thermal energy. A dominant role in all processes is attributed to the magnetic field, the measurement of which on the coronal levels can be performed by radio-astronomical techniques. The extension of the wavelength range and the introduction of new tools and advanced modeling capabilities makes it possible to analyze the physical properties of plasma structures in the AR magnetosphere and to evaluate the coronal magnetic fields at the levels of the chromosphere–corona transition zone and the lower corona. The features and characteristics of the transition region from the S component to the B component have been estimated.  相似文献   
252.
A wireless sensor system for data acquisition and processing during structural and fatigue tests is considered. A prototype of wireless strain-gauge measurement system is used in fatigue tests of a utility helicopter’s main rotor hub. The setup of the test rig and software are described.  相似文献   
253.
The paper studies different types of dampers for rotor supports of gas turbine engines (GTE). The advantages of hydrodynamic dampers are shown. Hydrodynamic dampers for GTE rotor supports are studied. A new design and technique of calculation are proposed for an adjustable hydrodynamic damper.  相似文献   
254.
In the paper, processes of high-energy electron beam interaction with plasma particles in a discharge channel of a stationary plasma thruster are analyzed and the results are presented.  相似文献   
255.
The results of designing the attitude control system of the first Russian nanosatellite TNS-0 no. 1 providing orientation of its longitudinal axis along the local geomagnetic field induction vector are presented. The system consists of a permanent magnet and two sets of hysteresis rods. The magnetic and geometric parameters of the magnet and rods are calculated. The influence of the permanent magnet field on the hysteresis rods and mutual influence of the rods in the case of compact satellite packaging are analyzed. Examples of calculations of transient processes and steady-state angular satellite motion are presented.  相似文献   
256.
Using the Earth albedo model and the orbital dynamics model developed as part of the First Look Project (Fast Initial In-Orbit Identification of Scientific Satellites) the terrestrial albedo is evaluated considering the orbits of some scientific missions as Gravity Probe B, MICROSCOPE and STEP. The model of the Earth albedo is based on the reflectivity data measured by NASA’s Earth Probe satellite, which is part of the TOMS project (Total Ozone Mapping Spectrometer). The reflectivity data are available daily, on line at the TOMS website, and they fluctuate because of changes in clouds and ice coverage and seasonal changes. The data resolution partitions the Earth surface into a number of cells. The incident irradiance on each cell is used to calculate total radiant flux from the cell. With the radiant flux from each cell, the irradiance at the satellite is calculated.  相似文献   
257.
The problem of determining the “potential” number of integration steps by explicit difference schemes is solved within the framework of the prediction model for chemically non-equilibrium processes.  相似文献   
258.
The Juno Waves Investigation   总被引:1,自引:0,他引:1  
Jupiter is the source of the strongest planetary radio emissions in the solar system. Variations in these emissions are symptomatic of the dynamics of Jupiter’s magnetosphere and some have been directly associated with Jupiter’s auroras. The strongest radio emissions are associated with Io’s interaction with Jupiter’s magnetic field. In addition, plasma waves are thought to play important roles in the acceleration of energetic particles in the magnetosphere, some of which impact Jupiter’s upper atmosphere generating the auroras. Since the exploration of Jupiter’s polar magnetosphere is a major objective of the Juno mission, it is appropriate that a radio and plasma wave investigation is included in Juno’s payload. This paper describes the Waves instrument and the science it is to pursue as part of the Juno mission.  相似文献   
259.
The paper discusses a method of designing the neural controller for two-channel control of a technical object by an example of the roll and yaw control depending on deviations, velocities and accelerations of their variation.  相似文献   
260.
The methodology is proposed and the mathematical model is developed for the purpose of numerical simulation of the power circuit of the gas-hydraulic actuator with displacing power source for the gimbaled nozzle control. It provides the highest power efficiency factor of the actuator as a part of aircraft by means of pulling together the profiles of available and required power.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号