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571.
The Coronal Diagnostic Spectrometer (CDS) on SOHO is a grazing/normal incidence spectrograph, aimed to produce stigmatic spectra of selected regions of the solar surface in six spectral windows of the extreme ultraviolet from 150 Å to 785 Å (Harrison et al. 1995). In the present work, CDS, EIT, MDI and Yohkoh observations of active region lops have been analyzed. These observations are part of JOP 54. CDS monochromatic images from lines at different temperatures have been co-aligned with EIT and MDI images, and loop structures have been clearly identified using Fe XVI emission lines. Density sensitive lines and lines from adjacent stages of ionization of Fe ions have been used to measure electron density and temperature along the loop length; these measurements have been used to determine the electron pressure along the loop and test the constant pressure assumption commonly used in loop modeling. The observations have been compared with a static, isobaric loop model (Landini and Monsignori Fossi 1975) assuming a temperature-constant heating function in the energy balance equation. Good agreement is found for the temperature distribution along the loop at the coronal level. The model pressure is somewhat higher than obtained from density sensitive line ratios. 相似文献
572.
573.
W. I. Axford J. F. McKenzie G. V. Sukhorukova M. Banaszkiewicz A. Czechowski R. Ratkiewicz 《Space Science Reviews》1999,87(1-2):25-41
We outline a theory for the origin and acceleration of the fast solar wind as a consequence of network microflares releasing
a spectrum of high frequency Alfvén waves which heat (by cyclotron absorption) the corona close to the Sun. The significant
features of our model of the fast wind are that the acceleration is rapid with the sonic point at around two solar radii,
the proton temperatures are high (~ 5 million degrees) and the minor ions are correspondingly hotter, roughly in proportion
to their mass. Moreover we argue that since the energy flux needed to power the quiet corona in closed field regions is about
the same as that needed to drive the fast solar wind, and also because at deeper levels (< 2 × 105 K) there is no great difference in the properties of supergranules and network in closed and open field regions, the heating
process (i.e., dissipation of high frequency waves) must be the same in both cases.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
574.
Vasiliev I.A. Ivashov S.I. Makarenkov V.I. Sablin V.N. Sheyko A.P. 《Aerospace and Electronic Systems Magazine, IEEE》1999,14(5):25-29
A subsurface radar using a multi-frequency signal has been developed. It is designated for surveying building structures and works. The characteristic feature of this device is the possibility of obtaining sounding plane radio images featuring a high resolution attaining 1…2 cm. The main applications of this device includes the survey of building structures to reveal their heterogeneities and defects and the investigation of premises to detect bugging devices 相似文献
575.
SOHO/UVCS data indicate that minor ions in the corona are heated more than hydrogen, and that coronal heating results in T⊥ larger than T‖. Analogous behavior has been known from in situ measurements in solar wind for many years. Here we compare and contrast two
mechanisms which have been proposed to account for the above behavior: ion-cyclotron resonance and gravity damping.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
576.
J F Bottollier-Depois F Spurny L Plawinski I Votockova J Bednar M Viso A Labarthe 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,22(4):517-520
The dosimetry of cosmic rays was performed during the first experimental flight of the IBIS facility. Different thermoluminescent detectors (TLD) have been used to measure the contribution of the low linear energy transfer component (LET < 10 keV/micrometer) and plastic nuclear track detectors (PNTD) for the high linear energy tranfer (LET) component. Several parameters of tracks have been measured to determine the LET spectra of primary and secondary charged particles. The total absorbed dose rate (TLD+PNTD) during the flight was 0.23 mGy/day and the dose equivalent rate using the ICRP 60 was 0.52 mSv/day. The corresponding mean quality factor was 2.4. These results are in agreement with those obtained aboard the MIR station with a tissue equivalent proportional counter. 相似文献
577.
I. V. Mingalev N. M. Astaf’eva K. G. Orlov V. M. Chechetkin V. S. Mingalev O. V. Mingalev 《Cosmic Research》2012,50(3):233-248
Mechanisms of formation of cyclonic vortices in the tropical atmosphere of the Earth are investigated in the intratropical
zone of convergence using numerical simulation made with the complete system of equations of gas dynamics taking into account
transport of infrared radiation, phase transitions of water vapor into microdrops of water and ice particles, and sedimentation
of these drops and ice particles in the field of gravity force. Observational data on the structure of dominant air streams,
which are formed in the intratropical zone of convergence over the North Atlantic in the periods of its highest thermodynamic
intensity and instability, are used in the initial and boundary conditions of the model. Formation of cyclonic vortex flows
is obtained numerically at sufficiently strong bending of the intratropical zone of convergence. The results of numerical
modeling are compared with the data of satellite microwave monitoring: global radio thermal fields of the Earth from the electronic
collection GLOBAL-Field allowing one to study the structure of atmospheric motions in a wide range of space-time scales. 相似文献
578.
Statistical studies of properties of the solar wind and interplanetary magnetic field, based on an extended database for the
period 1963–2007 including four solar cycles, show that the Gaussian approximation well suites for some parameters as the
probability distribution of their numerical values, while for others the lognormal law is preferred. This paper gives an interpretation
of these results as associated with predominance of linear or nonlinear processes in composition and interaction of various
disturbances and irregularities propagating and originating in the interior of the Sun and its atmosphere, including the solar
corona and the solar wind running away from it. Summation of independent random components of disturbances leads, according
to the central limit theorem of the probability theory, to the normal (Gaussian) distributions of quantities proper, while
their multiplication leads to the normal distributions of logarithms. Thus, one can discuss the algebra of events and associate
observed statistical distinctions with one or another process of formation of irregularities in the solar wind. Among them
there are impossible events (having null probability) and reliable events (occurring with 100% probability). For better understanding
of the relationship between algebra and statistics of events in the solar wind further investigations are necessary. 相似文献
579.
To determine the role of the support-proprioceptive factor in the functioning of the vestibular system, in particular the static torsional otolith–cervical–ocular reflex (OCOR), comparative OCOR studies with videooculography recording were performed after a 7-day “dry” horizontal immersion (16 subjects) and after a prolonged (126–195 days) exposure to weightlessness (13 cosmonauts). For the first time, it was demonstrated that minimization of the support and proprioceptive afferentation may result in an inversion or absence of the static torsional OCOR and the development of a positional nystagmus with an inverted reflex. A comparative OCOR data analysis of cosmonauts and immersion subjects has revealed similarity of responses. However, changes in OCOR after immersion were noted in only 60% of the subjects, while after space flight, 90% of cosmonauts showed them. Post-flight changes were more frequent, marked and long-lasting. Statistical analysis has shown that there were significant differences between pre- and post-flight data according to both parametric and non-parametric methods of multiple comparisons, whereas only parametric methods have found significant differences within immersion data. 相似文献
580.
A method for derivation of closed-form solutions for the differential Riccati matrix equation for specific time-varying systems is presented. It allows more insight into the nature of the solution. It reduces the on-line computation requirements, since it does not require on-line solution of a differential equation. Sufficient conditions for the existence of the closed-form solution are given. The method is applied to a target tracking problem 相似文献