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61.
We present a software package developed for the automatic 4-D stellar parameterization. The package can be adopted to virtually
any multicolour photometric system. Procedure of simultaneous determination of T
eff, log g, [M/H] and E
B-V is very flexible and can be performed by applying various photometric parameters(magnitudes, colour indices etc.). Any changes
of the photometric systems, weighting schemes or parameterization criteria can be implemented easily.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
62.
A new photometric system suitable for deep, precise and quick metallicity mapping in galaxies is proposed. We find a linear
correlation between our metallicity index and the Mg2 index for stellar, globular-cluster, and early-type galaxy spectra, and model spectral energy distributions of the simple
stellar populations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
63.
The CCD imagers have a spatial resolution comparable to the size of a constituent photosensitive cell. The modulation by means of a rotating Ronchi grating helps to exceed this limit. While the grating rotates in front of the CCD imager the counts of each cell are modulated thus producing a time-varying modulation pattern. The small systematic variations of the form of the pattern encode the fragment of the image pertaining to the cell. The images can be recovered from the modulation patterns by means of the least-squares as well as maximum entropy reconstruction technique. Both methods are able to decode the modulation patterns having high signal-to-noise ratio, however, maximum entropy reconstruction seems to be more robust. A gain in spatial resolution may be of the order of magnitude under favourable circumstances. 相似文献
64.
V. Straižys K. Zdana Vičius G. Tautvaišiene K. Černis 《Astrophysics and Space Science》1984,104(2):219-223
The photometry of G and K subdwarfs in the Vilnius photometric system permits us to recognize them photometrically and to determine their metallicity, despite the presence of interstellar reddening. The weakening of the strong metallic lines in their spectra can also be used to estimate their metallicity. 相似文献
65.
Attenuation Correction Procedures for Water Vapour Fluxes from Closed-Path Eddy-Covariance Systems 总被引:1,自引:1,他引:0
Benjamin R. K. Runkle Christian Wille Michal Gažovič Lars Kutzbach 《Boundary-Layer Meteorology》2012,142(3):401-423
Evapotranspiration is a source of water vapour to the atmosphere, and as a crucial indicator of landscape behaviour its accurate
measurement has widespread implications. Here we investigate errors that are prevalent and systematic in the closed-path eddy-covariance
measurement of latent heat flux: the attenuation of fluxes through dampened cospectral power at high frequencies. This process
is especially pronounced during periods of high relative humidity through the adsorption and desorption of water vapour along
the tube walls. These effects are additionally amplified during lower air temperature conditions. Here, we quantify the underestimation
of evapotranspiration by a closed-path system by comparing its flux estimate to simultaneous and adjacent measurements from
an open-path sensor. We apply models relating flux loss to relative humidity itself, to the lag time of the cross-correlation
peak between the water vapour and vertical wind velocity signals, and to models of cospectral attenuation relative to the
cospectral power of simultaneous sensible heat-flux measurements. We find that including the role of temperature in modifying
the attenuation–humidity relationship is essential for unbiased flux correction, and that physically based cospectral attenuation
methods are effective characterizers of closed-path instrument signal loss relative to the unattenuated flux value. 相似文献
66.
Palma Orlović-Leko Zlatica Kozarac Božena Ćosović Slađana Strmečki Marta Plavšić 《Journal of Atmospheric Chemistry》2010,66(1-2):11-26
Characterization of atmospheric surfactants in bulk precipitations was carried out by adsorption study at the mercury electrode/solution interface using phase sensitive AC voltammetry. The structure and permeability of the adsorbed organic films at the mercury electrode was tested using the redox processes of lead and cadmium ions as electrochemical tools. The effects of organic matter from the bulk precipitations (rainwater and melted snow) were compared to those obtained for aqueous solutions of model substances: aromatic hydrocarbon (naphtalene), anionic surfactant (sodium dodecylbenzene sulfonate, NDBS), protein (albumine) and selected model substances suggested to be representative of water soluble organic compounds (WSOC) in atmospheric water (monocarboxylic, dicarboxylic, and polyacidic compounds and levoglucosan). It was found that substances like humic acid and 3-hydroxybutanoic acid may play an important role in atmospheric heterogeneous chemistry because of their surface active potential. 相似文献
67.
Snezana Maletic Jelena Beljin Dragana Tamindzija Marko Grgic Jelena Molnar Jazic Marijana Kragulj Isakovski Srdan Roncevic 《国际泥沙研究》2021,36(4):479-488
The purpose of the current study is to compare the influence of different aerobic conditions(biostimulation(BS),bioaugmentation(BA),and a combination of biostimulation and bioaugmentation(BB))on polycyclic aromatic hydrocarbons(PAH)degradation and compare the degraded amount with single step XAD-4 extraction as a new tool for bioavailability assessment for chronically contaminated sediment samples obtained from territory of Autonomous Province Vojvodina of Serbia(S1,S2,and S3).A great number of papers dealing with biodegradation of PAHs in spiked sediment or soil have been published,but to the authors’knowledge,a limited number of papers studied aged,historically polluted sediment and a sum of chosen U.S.Environmental Protection Agency(USEPA)PAHs.A significant reduction(up to67%)in PAH concentration was observed,while the percentage of reduction varied depending on the sediment sample and treatment used.BS treatment successfully stimulated growth of indigenous bacteria.Further,PAH-degrading strain Sphingomonas paucimobilis F8 inoculated in BA and BB treatment survived for up to 7 weeks after it was suppressed by unfavorable conditions or native microbes.Degraded amounts generally showed good correlation with results obtained from XAD-4 extraction.Results obtained in the current study represent a good start for standardizing a XAD-4 extraction technique as a simplified,easier,and lower cost method for bioavailability assessment. 相似文献
68.
69.
The accumulation of sediment in river channels is a phenomenon that is not only influenced by the channel morphology, but also by the physical and geographical characteristics and the endogenous and exogenous processes taking place in the catchment. This paper presents an analysis of the impact the changes in lithological conditions have on the morphological and morphometric parameters of the Udava River channel and their relation to the channel accumulation forms representative of the river’s longitudinal profile as well as of its planform. Results document when accumulation forms occur and what is their spatial distribution within the longitudinal and cross-sectional river profiles. More resistant structures created sections with a lower degree of sedimentation, while in depression segments the degree of sedimentation was higher. With the increase in longitudinal slope, the impact of channel width on the average channel bar size increased. Also a difference in the accumulation was observed between the left and right bank which could be possibly explained by the impact of Coriolis force. 相似文献
70.
We analyze radio observations, magnetograms and extrapolated field line maps, Hα filtergrams, and X-ray observations of two
flare events (6 February 1992 in AR 7042 and 25 October 1994 in AR 7792) and study properties, evolution and energy release
signatures of sigmoidal loop systems. During both events, the loop configuration seen in soft X-ray (SXR) images changes from
a preflare sigmoidal shape to a relaxed post-flare loop system. The underlying magnetic field system consists of a quadrupolar
configuration formed by a sheared arcade core and a remote field concentration. We demonstrate two possibilities: a sigmoidal
SXR pattern can be due to a single continuous flux tube (the 1992 event). Alternatively, it can be due to a set of independent
loops appearing like a sigmoid (the 1994 event). In both cases, the preflare and post-flare loops can be well reproduced by
a linear force-free field and potential field, respectively, computed using preflare magnetograms. We find that thermal and
non-thermal flare energy release indicators of both events become remarkably similar after applying spatial and temporal scale
transformations. Using the spatial scaling between both events we estimated that the non-thermal energy release in the second
event liberated about 1.7 times more energy per unit volume. A two-and-a-half times faster evolution indicates that the rate
of the energy release per unit volume is more than four times higher in this event. A coronal type II burst reveals ignition
and propagation of a coronal shock wave. In contrast, the first event, which was larger and released about a 10 times more
energy during the non-thermal phase, was associated with a CME, but no type II burst was recorded. During both events, in
addition to the two-ribbon flare process an interaction was observed between the flaring arcade and an emerging magnetic flux
region of opposite polarity next to the dominant leading sunspot. The arcade flare seems to stimulate the reconnection process
in an `emerging flux-type' configuration, which significantly contributes to the energy release. This regime is characterized
by the quasiperiodic injection of electron beams into the surrounding extended field line systems. The repeated beam injections
excite pulsating broadband radio emission in the decimetric-metric wavelength range. Each radio pulse is due to a new electron
beam injection. The pulsation period (seconds) reflects the spatial scale of the emerging flux-type field configuration. Since
broadband decimetric-metric radio pulsations are a frequent radio flare phenomenon, we speculate that opposite-polarity small-scale
flux intrusions located in the vicinity of strong field regions may be an essential component of the energy release process
in dynamic flares. 相似文献