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71.
72.
We apply a multilayer feed-forward back propagation artificial neural network to a sample of 380 subdwarf spectra classified by Drilling et al. (Drilling, J.S., Moehler, S., Jeffery, C.S., Heber, U., and Napiwotzki, R.: in press in: R. Gray (ed.), Probing the Personalities of Stars and Galaxies), showing that it is possible to use this technique on large sets of spectra and obtain classifications in good agreement with the standard. We briefly investigate the impact of training set size, showing that large training sets do not necessarily perform significantly better than small sets. 相似文献
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74.
Herbert W. Schnopper Eric Silver Stephen Murray Suzanne Romaine Simon Bandler Christine Jones William Forman Norman Madden Jeffery Beeman Eugene Haller Finn Christensen Niels Westergaard Juan Fabregat Victor Reglero Alvaro Gimenez Noah Brosch Elia Liebowitz Hagai Netzer Marco Barbera Alfonso Collura Salvatore Sciortino 《Astrophysics and Space Science》2001,276(1):49-65
The X-Ray Spectroscopic Explorer (XRASE) has a unique combination of features that will make it possible to address many of NASA's scientific goals. These include how galaxy clusters form, the physics and chemistry of the ISM, the heating of stellar coronae, the amount and content of intergalactic baryonic matter, the mass of black holes and the formation of disks and jets in AGN and galactic binaries. XRASE has a thin foil, multilayered telescope with a large collecting area up to 10 keV, especially in the Fe K region (1100 cm2). Its microcalorimeter array combines high energy resolution (7 eV at 6 keV) and efficiency with a field-of-view of 26 arcmin2 . A deep orbit allows for long, continuous observations. Monitoring instruments in the optical (WOM-X), UV (TAUVEX) and hard X-RAY (GRAM) bands will offer exceptional opportunities to make simultaneous multi-wavelength observations. 相似文献
75.
Wide variations were measured in the diffuse CO2 flux through the soils in three selected areas of Mt Etna between August 1989 and March 1993. Degassing of CO2 from the area of Zafferana Etnea-S. Venerina, on the eastern slope of the volcano, has been determined to be more strongly influenced by meteorological parameters than the other areas. The seasonal component found in the data from this area has been excluded using a filtering algorithm based on the best fitting equation calculated from the correlation between CO2 flux values and those of air temperature. The filtered data appear to have variations temporally coincident with those from the other areas, thus suggesting a common and probably deep source of gas. The highest fluxes measured in the two most peripheral areas may correlate well with other geophysical and volcanological anomalous signals that preceded the strong eruption of 1991–1993 and that were interpreted as deep pressure increases. Anomalous decreases in CO2 fluxes accompanied the onset and the evolution of that eruption and have been interpreted as a sign of upward migration of the gas source. The variations of CO2 flux at the 1989 SE fracture have also given interesting information on the timing of the magmatic intrusion that has then fed the 1991–1993 eruption. 相似文献
76.
Heather Dunning Bonnie Janzen Allison Williams Sylvia Abonyi Bonnie Jeffery J. E. Randall Bill Holden Ronald Labonte Nazeem Muhajarine Gerry Klein Tracey Carr 《GeoJournal》2006,65(4):393-407
While many community initiatives have attempted to assess the nature and determinants of their citizens’ quality of life (QOL),
these initiatives have produced little about whether the key determinants of life quality differ by gender. Using both quantitative
and qualitative data from a recent QOL research project in Saskatoon, Saskatchewan, Canada, this study explores whether factors
that predict poor QOL are similar for women and men. The study also examines whether the nature of these gender differences
varies across low, medium and high socio-economic status locales. Results showed that men and women were very similar in:
(1) their QOL ratings, (2) reports of deterioration in neighborhood QOL, and (3) rating particular aspects of their neighborhood.
Few gender differences were also found when analyzing data referring to place characteristics and social cohesion. Multivariate
analysis revealed further similarities: (1) being divorced/widowed was a significant predictor of poor QOL, and (2) a negative
view of community security issues was associated with deterioration in perceived neighborhood quality of life. For women,
however, other variables were important predictors of QOL: being middle aged, being single, and having a poor opinion of the
overall quality of their neighborhood. Qualitative analysis revealed that while men and women shared concern about general
areas such as safety and neighborhood supports, their perceptions of the details around these issues differed. The multi-method
results suggest that urban policy actions should include a gendered discussion of common QOL issues. 相似文献
77.
Lora R. Stevens Jeffery R. Stone Josh Campbell Sherilyn C. Fritz 《Quaternary Research》2006,65(2):264-274
A 2200-yr long, high-resolution (∼5 yr) record of drought variability in northwest Montana is inferred from diatoms and δ18O values of bio-induced carbonate preserved in a varved lacustrine core from Foy Lake. A previously developed model of the diatom response to lake-level fluctuations is used to constrain estimates of paleolake levels derived from the diatom data. High-frequency (decadal) fluctuations in the de-trended δ18O record mirror variations in wet/dry cycles inferred from Banff tree-rings, demonstrating the sensitivity of the oxygen-isotope values to changes in regional moisture balance. Low frequency (multi-centennial) isotopic changes may be associated with shifts in the seasonal distribution of precipitation. From 200 B.C. to A.D. 800, both diatom and isotope records indicate that climate was dry and lake level low, with poor diatom preservation and high organic carbon: nitrogen ratios. Subsequently, lake level rose slightly, although the climate was drier and more stable than modern conditions. At A.D. 1200, lake level increased to approximately 6 m below present elevation, after which the lake fluctuated between this elevation and full stage, with particularly cool and/or wetter conditions after 1700. The hydrologic balance of the lake shifted abruptly at 1894 because of the establishment of a lumber mill at the lake's outlet. Spectral analysis of the δ18O data indicates that severe droughts occurred with multi-decadal (50 to 70 yr) frequency. 相似文献
78.
In this paper we have developed a new method for measuring in situ soil permeability, which is based on the theory of radial gas advection through an isotropic porous medium. The method was
tested in the laboratory and at several locations on the island of Vulcano (Aeolian Islands, Italy). It consists of a special
device which generates a gas source at a depth of 50 cm and it permits measurement of the relative induced pressure in nearby
soil at different depths. The characteristic error of the method was less than 10%.
Furthermore, soil permeability measurements were carried out in the island of Vulcano during different periods of the year
(between May 2000 and June 2001). A strong decrease in permeability in the upper layers of the soil during and after rainfall
was noted, with very poor correlations between the spatial
distributions of soil CO2 flux and shallow soil permeability. 相似文献
79.
Brent W. Ache Kristen M. Crossett Percy A. Pacheco Jeffery E. Adkins Peter C. Wiley 《Estuaries and Coasts》2015,38(1):151-155
Our nation’s coast is a complicated management area where no single delineation provides all of the demographic statistics needed to address the full range of policy and management issues. As a result, several different coastal delineations are currently being used, yielding a variety of US coastal population statistics. This paper proposes a simple model for generating and applying coastal population statistics at the national and regional level to increase consistency in coastal policy discussions and improve public understanding of coastal issues. The model includes two major components. The first component is “the population that most directly affects the coast,” represented by the permanent US population that resides in a standard suite of Coastal Watershed Counties, where land use and water quality changes most directly impact coastal ecosystems. The second component is “the population most directly affected by the coast,” represented by the permanent US population that resides in a standard suite of Coastal Shoreline Counties that are directly adjacent to the open ocean, major estuaries, and the Great Lakes, which due to their proximity to these waters, bear a great proportion of the full range of effects from coastal hazards and host the majority of economic production associated with coastal and ocean resources. 相似文献
80.