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91.
T. Lloyd Evans M. E. Hurst P. J. Sarre 《Monthly notices of the Royal Astronomical Society》2000,319(1):111-120
The optical spectrum of the carbon star IRAS 12311−3509 is dominated by the Merrill–Sanford emission bands of SiC2 , by absorption and emission in the Swan system of C2 , and by resonance emission lines of neutral metals. The infrared energy distribution is flat from 1 to 60 μm. These observations are interpreted as arising from a star with a cool dusty disc which is edge-on to the observer and obscures direct starlight. The infrared continuum is caused predominantly by absorption of stellar light by dust in the disc and re-emission at longer wavelengths. The optical stellar spectrum is seen by reflection off dusty material which lies out of the plane of the disc, and the molecular and atomic emission arises in the same geometry through resonance fluorescence. The object has similarities to the J-silicate stars, but may have a carbon-rich rather than oxygen-rich disc. A full spectroscopic assignment and discussion of the SiC2 bands and their intensities are given. Modelling of the rotational contours of the band yields a rotational temperature of 250 K, indicating very cool gas. 相似文献
92.
ArcGIS to Unity: a design pipeline for creation of 3D terrain in serious egames for geology 下载免费PDF全文
Annabeth Robinson Clare E. Gordon Jacqueline Houghton Geoffrey E. Lloyd Daniel J. Morgan 《Geology Today》2015,31(6):237-240
One of the key challenges during the development of the Virtual World Project ‘egame environment’ discussed in this issue was the creation of the digital virtual landscape from an original 2002 base map of a field area. In this [online] paper we will walk through the design pipeline that was developed by the virtual worlds project team, and discuss some of the issues that were discovered when translating from a 2D map to a 3D environment using available software, for others interested in replicating this work. 相似文献
93.
94.
Sara R. Heap Qian Gong Tony Hull Jeffrey Kruk Lloyd Purves 《Astrophysics and Space Science》2014,354(1):211-214
One of the key goals of NASA’s astrophysics program is to answer the question: How did galaxies evolve into the spirals and elliptical galaxies that we see today? We describe a space mission concept called Galaxy Evolution Spectroscopic Explorer (GESE) to address this question by making a large spectroscopic survey of galaxies at a redshift, z~1 (look-back time of ~8 billion years). GESE is a 1.5-m space telescope with an ultraviolet (UV) multi-object slit spectrograph that can obtain spectra of hundreds of galaxies per exposure. The spectrograph covers the spectral range, 0.2–0.4 μm at a spectral resolving power, R~500. This observed spectral range corresponds to 0.1–0.2 μm as emitted by a galaxy at a redshift, z=1. The mission concept takes advantage of two new technological advances: (1) light-weighted, wide-field telescope mirrors, and (2) the Next-Generation MicroShutter Array (NG-MSA) to be used as a slit generator in the multi-object slit spectrograph. 相似文献
95.
Centimeter-Level Positioning of a U. S. Coast Guard Buoy Tender 总被引:1,自引:1,他引:0
David B. Zilkoski J. Don D'Onofrio Rudolf J. Fury Curtis L. Smith Lloyd C. Huff Barry J. Gallagher 《GPS Solutions》1999,3(2):53-65
With the availability of high-accuracy, differential global positioning system (GPS) results in real-time, there is a new
opportunity to use GPS to accurately measure a marine vessel's dynamic draft (settlement and squat) and 3D attitude (roll,
pitch, and heading). The National Geodetic Survey (NGS) and the Coast Survey (CS), offices of the National Ocean Service (NOS),
National Oceanic and Atmospheric Administration (NOAA), propose to transfer this technology to the shipping industry. The
overall goal of this project is to provide the position of a vessel's keel in real time to within 10 cm (about 4 inches) relative
to the bottom of the shipping channel.
In support of this phase of the project, there were three meetings hosted by the Port of Oakland, California and NOS to discuss
the real-time positioning of vessels project. On December 3 and 4, 1996, CS, NGS, Trimble Navigation Ltd., and the U. S. Coast
Guard (USCG) performed GPS tests on a USCG buoy-tender ship. GPS data were used to compute the vessel's dynamic draft and
3D attitude. During the test, five receivers continually collected data; one receiver was located at a base station on the
USCG pier on Yerba Buena Island, and four were on the ship: two on the stern and two on the bow. CS installed a TSS-335B vertical
reference unit (to measure heave, pitch, and roll) in the engine room of the ship.
NOS processed the GPS data and computed the vessel's dynamic draft and 3D attitude. The results indicate that the linear equivalent
to the vessel's dynamic draft and 3D attitude were accurate to the 10-cm level using GPS. It was also demonstrated how a ship
can be used to measure local water-level changes and actual water-level values everywhere it travels. ? 1999 John Wiley &
Sons, Inc. 相似文献
96.
N. Kameswara Rao B. N. Ashoka C. Lloyd C. D. Pike D. J. Stickland 《Journal of Astrophysics and Astronomy》1990,11(4):445-460
A new radial velocity study has been made of the highly eccentric, early-type binary BD -1° 1004 using spectra from the Kavalur
Observatory. All available archival material has also been reexamined. An attempt has been made to correct for line ‘dragging’
by the secondary spectrum to improve the fit of the observed data to the orbital solutions. It is found that an earlier suggestion
of apsidal regression is still possible although ω is probably constant within the errors. There remain problems and inconsistencies
with other orbital elements, in particular K1 and γ 相似文献
97.
98.
J.V. Narlikar D. Lloyd N.C. Wickramasinghe M.J. Harris M.P. Turner S. Al-Mufti M.K. Wallis M. Wainwright P. Rajaratnam S. Shivaji G.S.N. Reddy S. Ramadurai F. Hoyle 《Astrophysics and Space Science》2003,285(2):555-562
The results of biological studies of a cryosampler flown with a balloon, in which air samples were collected at altitudes
ranging from 20 to 41 km, well above the Tropopause over Hyderabad, are described. In the analysis carried out in Cardiff,
voltage-sensitive dyes that could detect the presence of viable cells were used on these air-samples. Clumps of viable cells
were found to be present in samples collected at all the altitudes. The images obtained from electron microscopy are consistent
with the above finding. Reference is also made to another paper presented at this conference describing the identification
of bacterial species in the sample carried out in Sheffield. Counter arguments are discussed against the criticism that the
detected cells and microorganisms (in the samples collected above the local tropopause at 16 km) are due to terrestrial contamination.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
99.
100.
A new approach is demonstrated that permits a reliable estimate of specific yield using published values of the van Genuchten water retention parameters and effective grain sizes and the measured effective grain sizes of soil samples. The specific yield distribution of the soil texture was computed using the published values of the van Genuchten parameters. The specific yield values and the published values of effective grain sizes were then used to construct a specific yield–effective grain size curve, which estimates the ‘point’ specific yield of the soil samples. Applying the central limit theorem, the point specific yields could be transformed into an ‘areal’ specific yield for a study area. Compared with other commonly used approaches, the present procedure requires relatively low computational efforts and readily obtainable data. It is cost effective and does not depend on soil texture classification. More importantly, it incorporates the depth to water table and the variations in grain sizes inherent in natural soil conditions in the estimation. The approach developed was applied for estimating the specific yield of an unconfined sandy aquifer created by land reclamation in the equatorial region. The values obtained were compared with field measurements and the typical ranges of specific yield from the literature. Instead of a single estimate of the specific yield, the method yields a confidence interval with a high confidence level of 95% and with a narrower range than the typical ranges from the literature. In addition, the estimated values are close to the field measurements; hence, the procedure provides a cost‐effective alternative to field measurement. The applicability of the present approach could be extended to sites with heterogeneity in the horizontal direction. Nevertheless, the applicability of the present approach for layered soil profiles requires further evaluations. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献