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171.
Darren S. Madgwick Ed Hawkins Ofer Lahav Steve Maddox Peder Norberg John A. Peacock Ivan K. Baldry Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ian Lewis Stuart Lumsden Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2003,344(3):847-856
172.
Manuela Magliocchetti Steve J. Maddox Carole A. Jackson Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto de Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Ofer Lahav Ian Lewis Stuart Lumsden John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,333(1):100-120
173.
D. J. Croton E. Gaztañaga C. M. Baugh P. Norberg M. Colless I. K. Baldry J. Bland-Hawthorn T. Bridges R. Cannon S. Cole C. Collins W. Couch G. Dalton R. De Propris S. P. Driver G. Efstathiou R. S. Ellis C. S. Frenk K. Glazebrook C. Jackson O. Lahav I. Lewis S. Lumsden S. Maddox D. Madgwick J. A. Peacock B. A. Peterson W. Sutherland K. Taylor 《Monthly notices of the Royal Astronomical Society》2004,352(4):1232-1244
174.
Nelson D. Padilla Carlton M. Baugh Vincent R. Eke Peder Norberg Shaun Cole Carlos S. Frenk Darren J. Croton Ivan K. Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,352(1):211-225
175.
Geraint Harker Shaun Cole Adrian Jenkins 《Monthly notices of the Royal Astronomical Society》2007,382(4):1503-1515
We generate mock galaxy catalogues for a grid of different cosmologies, using rescaled N -body simulations in tandem with a semi-analytic model run using consistent parameters. Because we predict the galaxy bias, rather than fitting it as a nuisance parameter, we obtain an almost pure constraint on σ8 by comparing the projected two-point correlation function we obtain to that from the Sloan Digital Sky Survey (SDSS). A systematic error arises because different semi-analytic modelling assumptions allow us to fit the r -band luminosity function equally well. Combining our estimate of the error from this source with the statistical error, we find σ8 = 0.97 ± 0.06 . We obtain consistent results if we use galaxy samples with a different magnitude threshold, or if we select galaxies by b J -band rather than r -band luminosity and compare to data from the 2dF Galaxy Redshift Survey (2dFGRS). Our estimate for σ8 is higher than that obtained for other analyses of galaxy data alone, and we attempt to find the source of this difference. We note that in any case, galaxy clustering data provide a very stringent constraint on galaxy formation models. 相似文献
176.
When studying spatial patterns, GIScientists often employ distance‐based methods and techniques, such as network analysis. When studying human behavior, however, spatial patterns often emerge that cannot be adequately examined assuming a physical conceptualization of distance. Such patterns emerged during our study of the process of ghettoization of Jews as implemented in Budapest during the course of 1944. As part of an NSF‐sponsored research project on the geography of the Holocaust, we built a Historical GIS of the Budapest Ghetto with the objective of discovering patterns of Jewish concentration and dispersion as well as simulating potential daily spatial interactions between the Jewish and the non‐Jewish population. Spatial analytical techniques allowed us to discover distinct spatial patterns of isolation, interrelation and concentration, but a whole set of patterns appeared that were the opposite of what we expected, and that could only be explained by thinking of distance not in spatial terms but in social ones. In this article we employ social network analysis to examine the geography of oppression in the Budapest ghetto. What jumped out from our study is the interweaving of space and place – intended as a community bounded by social relations and living in a specific time and location. 相似文献
177.
C. D’Oriano R. Cioni A. Bertagnini D. Andronico P. D. Cole 《Bulletin of Volcanology》2011,73(6):699-715
Recent stratigraphic studies at Vesuvius have revealed that, during the past 4,000 years, long lasting, moderate to low-intensity
eruptions, associated with continuous or pulsating ash emission, have repeatedly occurred. The present work focuses on the
AS1a eruption, the first of a series of ash-dominated explosive episodes which characterized the period between the two Subplinian
eruptions of 472 AD and 1631 AD. The deposits of this eruption consist of an alternation of massive and thinly laminated ash
layers and minor well sorted lapilli beds, reflecting the pulsatory injection into the atmosphere of variably concentrated
ash-plumes alternating with Violent Strombolian stages. Despite its nearly constant chemical composition, the juvenile material
shows variable external clast morphologies and groundmass textures, reflecting the fragmentation of a magma body with lateral
and/or vertical gradients in both vesicularity and crystal content. Glass compositions and mineralogical assemblages indicate
that the eruption was fed by rather homogeneous phonotephritic magma batches rising from a reservoir located at ~ 4 km (100 MPa)
depth, with fluctuations between magma delivery and magma discharge. Using crystal size distribution (CSD) analyses of plagioclase
and leucite microlites, we estimate that the transit time of the magma in the conduit was on the order of ~ 2 days, corresponding
to an ascent rate of around 2 × 10−2 ms−1. Accordingly, assuming a typical conduit diameter for this type of eruption, the minimum duration of the AS1a event is between
about 1.5 and 6 years. Magma fragmentation occurred in an inertially driven regime that, in a magma with low viscosity and
surface tension, can act also under conditions of slow ascent. 相似文献
178.
T. M. Wilson J. W. Cole C. Stewart S. J. Cronin D. M. Johnston 《Bulletin of Volcanology》2011,73(3):223-239
Tephra fall from the August 1991 eruption of Volcán Hudson affected some 100,000 km2 of Patagonia and was almost immediately reworked by strong winds, creating billowing clouds of remobilised ash, or ‘ash storms’.
The immediate impacts on agriculture and rural communities were severe, but were then greatly exacerbated by continuing ash
storms. This paper describes the findings of a 3-week study tour of the diverse environments of southern Patagonia affected
by ash storms, with an emphasis on determining the impacts of repeated ash storms on agriculture and local practices that
were developed in an attempt to mitigate these impacts. Ash storms produce similar effects to initial tephra eruptions, prolonged
for considerable periods. These have included the burial of farmland under dune deposits, abrasion of vegetation and contamination
of feed supplies with fine ash. These impacts can then cause problems for grazing animals such as starvation, severe tooth
abrasion, gastrointestinal problems, corneal abrasion and blindness, and exhaustion if sheep fleeces become laden with ash.
In addition, ash storms have led to exacerbated soil erosion, human health impacts, increased cleanup requirements, sedimentation
in irrigation canals, and disruption of aviation and land transport. Ash deposits were naturally stabilised most rapidly in
areas with high rainfall (>1,500 mm/year) through compaction and enhanced vegetation growth. Stabilisation was slowest in
windy, semi-arid regions. Destruction of vegetation and suppression of regrowth by heavy tephra fall (>100 mm) hindered the
stabilisation of deposits for years, and reduced the surface friction which increased wind erosivity. Stabilisation of tephra
deposits was improved by intensive tillage, use of windbreaks and where there was dense and taller vegetative cover. Long-term
drought and the impracticality of mixing ash deposits with soil by tillage on large farms was a barrier to stabilising deposits
and, in turn, agricultural recovery. The continuing ash storms motivated the partial evacuation of small rural towns such
as Chile Chico (Chile) and Los Antiguos (Argentina) in September–December 1991, after the primary tephra fall in August 1991.
Greatly increased municipal cleanup efforts had to be sustained beyond the initial tephra fall to cope with the ongoing impacts
of ash storms. Throughout the 1990s, ash storms contributed to continued population migration out of the affected area, leaving
hundreds of farms abandoned on the Argentine steppe. The major lesson from our study is the importance of stabilisation of
ash deposits as soon as possible after the initial eruption, particularly in windy, arid climates. Suggested mitigation measures
include deep cultivation of the ash into the soil and erecting windbreaks. 相似文献
179.
Ekaterina Bazilevskaya Marina Lebedeva Milan Pavich Gernot Rother Dilworth Y. Parkinson David Cole Susan L. Brantley 《地球表面变化过程与地形》2013,38(8):847-858
Weathering disaggregates rock into regolith – the fractured or granular earth material that sustains life on the continental land surface. Here, we investigate what controls the depth of regolith formed on ridges of two rock compositions with similar initial porosities in Virginia (USA). A priori, we predicted that the regolith on diabase would be thicker than on granite because the dominant mineral (feldspar) in the diabase weathers faster than its granitic counterpart. However, weathering advanced 20× deeper into the granite than the diabase. The 20 × ‐thicker regolith is attributed mainly to connected micron‐sized pores, microfractures formed around oxidizing biotite at 20 m depth, and the lower iron (Fe) content in the felsic rock. Such porosity allows pervasive advection and deep oxidation in the granite. These observations may explain why regolith worldwide is thicker on felsic compared to mafic rock under similar conditions. To understand regolith formation will require better understanding of such deep oxidation reactions and how they impact fluid flow during weathering. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
180.
Inmaculada de Vicente Eva Ortega-Retuerta Ignacio P. Mazuecos Michael L. Pace Jonathan J. Cole Isabel Reche 《Aquatic Sciences - Research Across Boundaries》2010,72(4):443-453
In inland waters, transparent exopolymer particles (TEP) can affect carbon export and sequestration in sediments with consequences
for lake C budgets. We measured TEP concentration in 32 lakes from two contrasting lake districts covering wide ranges in
biological and chemical characteristics. North temperate lakes, located in a wet region, have low to moderate ionic strength
and low to high dissolved organic carbon with corresponding variation in color (light absorbance). Mediterranean lakes located
in a semiarid region were characterized by high ionic strength and high concentrations of dissolved organic carbon but low
color. TEP concentrations were large relative to the living portion of the particulate organic carbon pool in both Mediterranean
(36%) and north temperate (33%) lakes. TEP concentrations ranged from 36 to 1,462 μg [as Gum Xanthan equivalents (GX eq)] L−1 in north temperate lakes. In the Mediterranean lakes, concentrations were higher that previously reported for other systems
and ranged from 66 to 9,038 μg GX eq L−1. TEP concentration was positive and significantly related to chlorophyll a (chl a) in north temperate lakes and in the entire data set. Although a significant and positive relationship between TEP and chl
a was also detected in the Mediterranean lakes, bacterial abundance was most strongly related to TEP. In contrast with the
positive influence of phytoplankton and bacteria on TEP, there were weaker relationships between TEP and the chemical variables
tested. We observed a significant and positive relationship between pH and TEP (for all lakes) but this relationship was indirectly
driven by a co-variation of pH with phytoplankton biomass based on multiple regression analysis. For the Mediterranean lakes,
the negative (but not significant) trends between TEP and both conductivity and divalent cations suggest thresholds above
which TEP will likely be destabilized. Under these conditions, TEP may flocculate or disperse in the water column. 相似文献