全文获取类型
收费全文 | 67篇 |
免费 | 0篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 6篇 |
地球物理 | 12篇 |
地质学 | 15篇 |
海洋学 | 22篇 |
天文学 | 10篇 |
自然地理 | 1篇 |
出版年
2017年 | 1篇 |
2016年 | 2篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2006年 | 1篇 |
2004年 | 3篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1993年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1877年 | 1篇 |
排序方式: 共有67条查询结果,搜索用时 31 毫秒
1.
Gallo D. G. Kidd W. S. F. Fox P. J. Karson J. A. Macdonald K. Crane K. Choukroune P. Seguret M. Moody R. Kastens K. 《Marine Geophysical Researches》1984,6(2):159-185
During the Fall of 1979, a manned submersible program, utilizing DSRV ALVIN, was carried out at the intersection of the East Pacific Rise (EPR) with the Tamayo Transform boundary. A total of seven dives were completed in the vicinity of the EPR/Tamayo intersection depression and documented the geologic relationships that characterize the juxtaposition of these types of plate boundaries. The young volcanic terrain of the EPR axis can be traced into and across the Tamayo Transform valley but becomes buried by sedimentary talus that is being shed from sediment scarps along the unstable sediment slope that defines the north side of the intersection depression. Within 4 km of the transform boundary, the dominant trend (000°) of the fissures and faults that disrupt the rise-generated volcanics is markedly oblique to the regional direction of sea floor spreading (120°). Since no evidence was found to suggest that these structures accommodate significant amounts of strike-slip displacement, they are taken to reflect a distortion of the EPR extensional tectonic regime by a transform generated shear couple. The floor of the Tamayo Transform valley in this area is inundated by mass-wasted sediment, and the principal transform displacement zone is characterized at the surface by a narrow (<1.5 km) interval of fault scarps in sediment that trends parallel with the transform valley. Extrapolated to the west, this zone links with zones of transform deformation investigated during earlier submersible studies (CYAMEX and Pastouret, 1981). Evidence of low-level hydrothermal discharge was seen at one locality on the EPR axis and at another 8 km west of the axis at the edge of the zone of transform deformation. 相似文献
2.
3.
4.
P. J. Boyce M. J. Disney J. C. Blades A. Boksenberg P. Crane J. M. Deharveng F. D. Macchetto C. D. Mackay & W. B. Sparks 《Monthly notices of the Royal Astronomical Society》1998,298(1):121-130
We present Hubble Space Telescope ( HST ) images of seven low-redshift quasars (six taken with the Planetary Camera, one with the Wide Field Camera). These complete the sample of 14 quasars observed by the Faint Object Camera Investigation Definition Team (FOC IDT). Following subtraction of the quasar nuclear light, host galaxies can be seen in all seven cases. A combination of the optical morphology and luminosity profiles of the residual host galaxies and the results of 2D cross-correlation model fitting implies that five of the objects have elliptical host galaxies and two have disc host galaxies. The luminosities vary from slightly fainter than L * to about 1.3 mag brighter than L * . We discuss the properties of the complete sample of 14 quasars. Nine of the objects appear to have elliptical host galaxies (all six of the radio-loud quasars in the sample as well as three radio-quiet quasars). Two further radio-quiet quasars appear to lie in disc galaxies. The other three objects (radio-quiet, ultraluminous infrared quasars) all lie in violently interacting systems. The sample as a whole has an average luminosity about 0.8 mag brighter than L * , although the radio-loud objects have hosts on average 0.7 mag brighter than the radio-quiet objects. We compare our results with those from HST imaging of quasars by other authors. Taken together, our observations are in broad agreement with those of Bahcall et al. Radio-loud quasars appear to lie in luminous elliptical galaxies whereas radio-quiet quasars are found to lie in either elliptical or spiral hosts. Host galaxy luminosities (of radio-quiet and radio-loud quasars) are much brighter than would be expected if they followed a Schechter luminosity function. 相似文献
5.
6.
Side-scan sonar mapping and ground-truthing of the Norwegian–Barents–Svalbard continental margin shed new light on shelf glaciation, mass wasting, hydrates, and features like the Håkon Mosby mud volcano (HMMV), reflecting upward mobility of gas, pore fluids, and sediments. Detailed HMMV examination revealed thermal gradients to 10°/m, bottom-water CH4 and temperature anomalies, H2S- and CH4-based chemosynthetic ecosystems, and subbottom methane hydrate (to 25%). Seismic and chemical data suggest HMMV origins at 2–3?km depth within the 6-km-thick depocenter. The HMMV and mound fields bordering the Bjørnøyrenna slide valley and pockmarks bordering the Storegga slide may all have formed in response to sediment failure. 相似文献
7.
Krijn P. Paaijmans Justine I. Blanford Robert G. Crane Michael E. Mann Liang Ning Kathleen V. Schreiber Matthew B. Thomas 《Climatic change》2014,125(3-4):479-488
The potential impact of climate warming on patterns of malaria transmission has been the subject of keen scientific and policy debate. Standard climate models (GCMs) characterize climate change at relatively coarse spatial and temporal scales. However, malaria parasites and the mosquito vectors respond to diurnal variations in conditions at very local scales. Here we bridge this gap by downscaling a series of GCMs to provide high-resolution temperature data for four different sites and show that although outputs from both the GCM and the downscaled models predict diverse but qualitatively similar effects of warming on the potential for adult mosquitoes to transmit malaria, the predicted magnitude of change differs markedly between the different model approaches. Raw GCM model outputs underestimate the effects of climate warming at both hot (3-fold) and cold (8–12 fold) extremes, and overestimate (3-fold) the change under intermediate conditions. Thus, downscaling could add important insights to the standard application of coarse-scale GCMs for biophysical processes driven strongly by local microclimatic conditions. 相似文献
8.
A new technique of Fourier analysis, DFT/CLEAN, has been adapted for the study of solar time series. The technique was developed
by Roberts and his collaborators (1987, 1994) to address the limitations of other techniques of Fourier analysis and the shortcomings
of many astronomical time series. The utility of the technique is illustrated with several applications to solar time series. 相似文献
9.
10.
Stochastic finite-fault modeling is an important tool for simulating moderate to large earthquakes. It has proven to be useful in applications that require a reliable estimation of ground motions, mostly in the spectral frequency range of 1 to 10 Hz, which is the range of most interest to engineers. However, since there can be little resemblance between the low-frequency spectra of large and small earthquakes, this portion can be difficult to simulate using stochastic finite-fault techniques. This paper introduces two different methods to scale low-frequency spectra for stochastic finite-fault modeling. One method multiplies the subfault source spectrum by an empirical function. This function has three parameters to scale the low-frequency spectra: the level of scaling and the start and end frequencies of the taper. This empirical function adjusts the earthquake spectra only between the desired frequencies, conserving seismic moment in the simulated spectra. The other method is an empirical low-frequency coefficient that is added to the subfault corner frequency. This new parameter changes the ratio between high and low frequencies. For each simulation, the entire earthquake spectra is adjusted, which may result in the seismic moment not being conserved for a simulated earthquake. These low-frequency scaling methods were used to reproduce recorded earthquake spectra from several earthquakes recorded in the Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation Models (NGA) database. There were two methods of determining the stochastic parameters of best fit for each earthquake: a general residual analysis and an earthquake-specific residual analysis. Both methods resulted in comparable values for stress drop and the low-frequency scaling parameters; however, the earthquake-specific residual analysis obtained a more accurate distribution of the averaged residuals. 相似文献