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201.
Gerardo Benito Andrés Díez-Herrero María Fernández de Villalta 《Climatic change》2003,58(1-2):171-192
A relational database using Access, and an interface based on a Geographical Information System (GIS) with ArcView program, were created to allow spatial-temporal analysis of documentary flood data collected for the Tagus basin (Central Spain). High flood frequencies were registered in the periods: AD 1160–1210 (3%), 1540–1640 (11%; peak at 1590–1610), 1730–1760 (5%), 1780–1810 (4%), 1870–1900 (19%), 1930–1950 (17%) and 1960–1980 (12%). Flood magnitudes of those documentary events were estimated at four sites (Aranjuez, Toledo, Talavera and Alcántara) along the Tagus River using HEC-RAS Computer program, matching the calculated water surface profiles with historical references of flood stage. The largest floods took place during the periods AD 1168–1211 (Toledo and Talavera), AD 1658–1706 (Talavera), AD 1870–1900, and AD 1930–1950 (Aranjuez, Toledo, Talavera and Alcántara). The temporal distribution of flood magnitude and frequency is discussed within the context of climatic variability experienced by the Iberian Peninsula. Although flood producing mechanisms of Atlantic and Mediterranean basins of the Iberian Peninsula are related to different, independent atmospheric patterns, there is a clear coincidence between most periods showing high flood frequencies. These periods of high flooding seem to correspond to the initial and final decades of periods with climate deterioration described at the continental scale. This suggests that climatic variability over the last millennium has induced a response in hydrological extremes (positive or negative), irrespective of the flood-producing mechanism. 相似文献
202.
Leonardo Alvarez Julio García Franco Vaccari Giuliano F. Panza Bertha González Carmen Reyes Bárbara Fernández Ramón Pico José A. Zapata Enrique Arango 《Pure and Applied Geophysics》2004,161(5-6):1041-1059
— The expected ground motion in Santiago de Cuba basin from earthquakes which occurred in the Oriente fault zone is studied. Synthetic SH-waves seismograms have been calculated along four profiles in the basin by the hybrid approach (modal summation for the path source-profile and finite differences for the profile) for a maximum frequency of 1 Hz. The response spectra ratio (RSR) has been determined in 49 sites, distributed along all considered profiles with a spacing of 900 m. The corresponding RSR versus frequency curves have been classified using a logical-combinatorial algorithm. The results of the classification, in combination with the uppermost geological setting (geotechnical information and geological geometry of the subsoil) are used for the seismic zoning of the city. Three different main zones are identified, and a small sector characterized by major resonance effects, due to the particular structural conditions. Each zone is characterized in terms of its expected ground motion parameters for the most probable strong earthquake (MS=7), and for the maximum possible (MS=8). 相似文献
203.
The fate of trace elements in a large coal-fired power plant 总被引:5,自引:1,他引:5
A quick approach is proposed to evaluate the environmental fate of trace elements in coal-fired power plants. It is based
on the analysis of feed coal and solid combustion by-products, together with the leachates of the latter. The application
of this method in a 1050 MW power plant from NE Spain shows that: (1) Ba, Ce, Co, Cs, Cu, Dy, Ga, Ge, La, Lu, Mn, Ni, Rb,
Sr, Tb, Th, Y, Yb, Zn and Zr were retained in the solid wastes; (2) As, B, Be, Cd, Cr, Li, Mo, Pb, Sb, Sn, Ta, Tl, U, V and
W were only partially retained in the solid wastes; and (3) Hg and Se were primarily emitted to the atmosphere.
Received: 2 February 2000 · Accepted: 18 May 2000 相似文献
204.
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206.
Unusually severe or prolonged drought ranks among the most devastating and calamitous of all extreme climate events, contributing
to wildfires, crop failure, livestock death, food shortages and famine. The response of human activities and the natural environment
to such historical weather perturbations provides a guide to where the most critical sensitivities to future climate changes
may lie (McCarthy et al., 2001, ‘Climatic change 2001: Impact adaptation, and vulnerability’, from 3rd Assesment Report of
IPCC). The reconstruction of regional climatic histories and investigations of the impacts of – and social response to – extreme
droughts in history are thus of crucial significance if we are to understand and anticipate the potential repercussions of
future events (Wigley, 1985, Nature 316, 106–107; Grove and Conterio, 1995, Clim. Change 30, 223).
Chihuahua, in the arid Northwest of Mexico, is one of the most seriously and frequently drought affected regions of the country
(Garcia, 2000, available at www.sequia.edu.mx/proyectos/vulnera.html). Prolonged drought in the 1930s, 1950s and 1990s contributed
to water scarcity, harvest failure, illness, livestock disease, abandonment and water conflict and served to highlight the
particular vulnerability of agrarian society in this region to climatic variability (Sandoval, 2003, Ingeneria Hidraulica en Mexico 18(2), 133–155). Recent investigations using tree ring analysis have identified several phases of such prolonged drought over
the last seven centuries. In this paper we use archival documents to investigate the impacts of such periods in late colonial
Chihuahua and to explore how society in the region responded to and coped with them. 相似文献
207.
J. A. González Martín V. Rubio Fernández R. García Giménez Raimundo Jiménez Ballesta 《Environmental Geology》2007,51(7):1093-1102
In this work we study one of the most palaeopedological sequence formed in Central Spain, which is located on the Pliocene–Pleistocene
erosional surface in the Madrid Basin. We also analyse its relationship to erosive and sedimentary Pleistocene events in order
to obtain new data for a correct interpretation of the origin and evolution of forms at the top of tabular lands in this site.
The geomorphic features and the properties of a sequence of very red palaeosols that developed on this old surface can help
us in the understanding of the palaeoclimatic evolution of Central Spain in a Mediterranean climate. They were examined to
identify pedologic and climatic changes during the Quaternary. The soil sequence comprises intercalated palaeoargillic and
palaeopetrocalcic horizons. The clay minerals are mainly illite, kaolinite, smectite and sepiolite. The alternation of argillic
and calcic horizons, limestone debris (cryoclastic colluvions) and aeolian sands suggests succeeding periods of phytostability
and phytoinstability (biostasis/rhexistasis). Argillation, rubification and calcium carbonate accumulation were repeated throughout
the Pleistocene and it is hypothesised that climatic conditions during numerous stages of this period were not very different
from the present conditions. 相似文献
208.
Groundwater arsenic distribution in South-western Uruguay 总被引:1,自引:0,他引:1
A. Manganelli C. Goso R. Guerequiz J. L. Fernández Turiel M. García Vallès D. Gimeno C. Pérez 《Environmental Geology》2007,53(4):827-834
This is the first specific information regarding arsenic distribution of groundwater in SW Uruguay. Twenty-eight wells were
sampled on the aquifers of Mercedes, Raigón and Chuy in five localities. The pH, specific conductivity and temperature were
determined in the field. The hydrochemical characterization (major and trace elements) was carried out by both inductively
coupled plasma-optical emission spectrometry and inductively coupled plasma-mass spectrometry. The occurring arsenic concentrations
exceed the recommended threshold for drinking water of the World Health Organization (10 μg/l of As) in 22 samples, with more
than 50 μg/l of As in two cases. The median, minimum and maximum concentrations were 0.1, 16.9 and 58.0 μg/l of As, respectively.
The studied aquifers present a horizontal and a vertical variation of the concentrations as a whole as well as individually.
The highest values were observed in the Mercedes Aquifer in the areas near the Uruguay River. 相似文献
209.
210.
M. D. Ruiz-Medina J. M. Angulo R. Fernández-Pascual 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(3):273-281
A wavelet-based orthogonal decomposition of the solution to stochastic differential/pseudodifferential equations of parabolic
type is derived in the cases of random initial conditions and random forcing. The family of spatiotemporal models considered
can represent anomalous diffusion processes when the spatial operator involved is a fractional or multifractional pseudodifferential
operator. The results obtained are applied to the generation of the sample paths of Gaussian spatiotemporal random fields
in the family studied. 相似文献