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381.
P. Bruno M. Caselli G. de Gennaro L. de Gennaro M. Tutino 《Journal of Atmospheric Chemistry》2006,54(2):177-187
Atmospheric concentrations of benzene and toluene were assessed during three different seasons in the city of Taranto, using Radiello® diffusive samplers, in order to detect the most critical areas and to point out the sources contributing to pollution (vehicular traffic or industrial activities). High spatial resolution maps were built using a grid of 30 meshes drawn on the urban area of the city. For each mesh a monitoring site as representative as possible was chosen. Besides, in order to describe the highest levels of pollutants to which people is exposed, other 10 sampling sites were detected near high vehicular traffic crossroads or in particular critical zones of the city. The measurements of the concentration of these pollutants were carried out with Radiello® diffusive samplers for thermal desorption. The analysis of the results and the comparison between the map of vehicular traffic flows and the map of the concentrations of benzene suggested that in urban area the main benzene source is the traffic and the most significant pollution phenomena happens in zones characterized by narrow roads. Moreover it was possible to observe that high concentrations of benzene found in the NE zone of Taranto could be assigned to the industrial activities. This hypothesis was confirmed considering the diagnostic ratio between the toluene and benzene concentrations. 相似文献
382.
A Probabilistic Modelling System for Assessing Flood Risks 总被引:4,自引:2,他引:4
In order to be economically viable, flood disaster mitigation should be based on a comprehensive assessment of the flood risk.
This requires the estimation of the flood hazard (i.e. runoff and associated probability) and the consequences of flooding
(i.e. property damage, damage to persons, etc.). Within the “German Research Network Natural Disasters” project, the working
group on “Flood Risk Analysis” investigated the complete flood disaster chain from the triggering event down to its various
consequences. The working group developed complex, spatially distributed models representing the relevant meteorological,
hydrological, hydraulic, geo-technical, and socio-economic processes. In order to assess flood risk these complex deterministic
models were complemented by a simple probabilistic model. The latter model consists of modules each representing one process
of the flood disaster chain. Each module is a simple parameterisation of the corresponding more complex model. This ensures
that the two approaches (simple probabilistic and complex deterministic) are compatible at all steps of the flood disaster
chain. The simple stochastic approach allows a large number of simulation runs in a Monte Carlo framework thus providing the
basis for a probabilistic risk assessment. Using the proposed model, the flood risk including an estimation of the flood damage
was quantified for an example area at the river Rhine. Additionally, the important influence of upstream levee breaches on
the flood risk at the lower reaches was assessed. The proposed model concept is useful for the integrated assessment of flood
risks in flood prone areas, for cost-benefit assessment and risk-based design of flood protection measures and as a decision
support tool for flood management. 相似文献
383.
Emilie Janots Franois Negro Fabrice Brunet Bruno Goff Martin Engi Mohamed L. Bouybaoune 《Lithos》2006,87(3-4):214-234
REE mineralogy was characterized at the micrometer scale (using scanning electron microscopy) in the four tectono-metamorphic units of the Beni Mzala window, Sebtide Complex, Internal Rif, Morocco, which sample a HP-LT metamorphic gradient from subgreenschist to blueschist/eclogite facies. These tectonic units are composed of garnet-free metapelites (and associated synmetamorphic veins) from the same homogeneous aluminium-rich and calcium-poor protolith. In that context, mineralogical differences between units are assumed to result from contrasted pressure and temperature histories. Light REE-bearing Al-phosphates of the crandallite group with florencite-rich composition and variable goyazite content are the dominant LREE minerals in the lowest-grade units, Tizgarine (300 °C, 3 kbar as peak conditions) and Boquete de Anjera (350 °C, 10 kbar). In the latter unit, metamorphic florencite is associated with MREE-rich monazite. In the schist of the highest-grade units, Beni Mzala 2 (420–450 °C, 12 kbar) and Beni Mzala 1 (550 °C, 16 kbar), associations of allanite-rich epidote and synchisite (a LREE-fluorocarbonate) are found whereas florencite and monazite are no longer observed. At the wall of the quartz–kyanite veins, retrograde monazite-(Ce) with grain size of 20 to 50 μm is the only LREE-bearing mineral. Th–Pb and U–Pb SIMS data on some of these grains yield ages of 21.3 ± 1.7 Ma and 20.9 ± 2.1 Ma, respectively, consistent with previous K–Ar ages obtained on retrograde clay–mica mixtures in rocks from the same locality. The identification of a stability field for monazite in high-pressure aluminous metapelites with an upper thermal-limit below 450 °C as well as the derivation of meaningful U–Pb and Th–Pb SIMS ages demonstrates the monazite potential for dating HP-LT metapelites. However, since, under these conditions, monazite growth occurs below its admitted closure-temperature, these ages must be interpreted on the basis of monazite textural relationships. 相似文献
384.
Riccardo Caputo Bruno Helly Spyros Pavlides Gerassimos Papadopoulos 《Natural Hazards》2006,39(2):195-212
Northern Thessaly may represent an important seismic gap within the broader Aegean Region, with major faults bordering the
ESE–WNW trending Late Pleistocene–Holocene Tyrnavos Basin. In order to obtain information about the characteristics of past
earthquakes and improve our knowledge on the seismic potential of the investigated area, historical and archaeological observations
are analysed and compared with the results of palaeoseismological trenches excavated across one of the major bordering structures,
the Tyrnavos Fault. The former data clearly document (i) a strong seismic activity affecting the area during the last 2–3 ka
and (ii) the occurrence of recent earthquakes not included in the seismic catalogues. Also, the sedimentological, structural
and chronological data (TL, OSL and AMS) obtained from the palaeoseismological trenches indicate Late Pleistocene to Holocene
morphogenic activity of the Tyrnavos Fault, characterised by vertical co-seismic displacements of 20–40 cm and possible return
periods of a few thousands of years. Advantages and limitations in using historical and archaeoseismological data are discussed,
as well as the problems arising from analysing low slip-rate faults. 相似文献
385.
386.
A well-diversified fauna of stalked crinoids was found in the Eocene series exposed in the quarry of Miretrain at Angoumé (Landes, southwestern Aquitaine, northern edge of the Tercis diapir structure). The most frequent taxa belong to the genera Isselicrinus and Conocrinus. Adaptive stalk characters related to depth in the pentacrinid genus Isselicrinus allow us to document the bathymetric zonation of stalked crinoids during the Eocene. Both stalked crinoids, benthic foraminifera and additional organisms give convergent information on palaeodepths throughout the progradation of sedimentary bathyal slope between the two major tectonic events providing Pyrenean foreland shortening. The depth changes from more than 700 m (maybe about 1000 m) at the base of the series (Middle Lutetian) to about 50 m at the top (Late Bartonian). To cite this article: M. Roux et al., C. R. Geoscience 338 (2006). 相似文献
387.
388.
This study was aimed at modeling, as realistically as possible, the dynamics and thermodynamics of the Iroise Sea by using
the Model for Applications at Regional Scale (MARS), a regional ocean 3D model. The horizontal resolution of the configuration
in use is 2 km with 30 vertical levels. The 3D model of the Iroise Sea is embedded in a larger model providing open boundary
conditions. As regards the atmospheric forcing, the originality of this study is to force the regional ocean model with the
high-resolution (6 km) regional meteorological model, Weather Research and Forecasting (WRF). In addition, as the air surface
temperature is highly sensitive to the sea surface temperature (SST), this regional meteorological model is improved by taking
into account a regional climatologic SST to compute meteorological parameters. By allowing a better coherence between the
SST and the temperature of the atmospheric boundary layer while giving a more realistic representation of heat fluxes exchanged
at the air/sea interface, this forcing constitutes a noticeable improvement of the Iroise Sea modeling. The different sensitivity
tests discussed here pinpoint the importance of entering, in WRF, SST data of sufficiently high quality before the computation
of meteorological forcing when the aim is a study of dynamics and thermodynamics far away from the coast. On the other hand,
when the target is the reproduction of coastal small-scale features in Iroise Sea modeling, the resolution of the meteorological
forcing and the quality of SST are both paramount. The simulation of reference was carried out throughout the Summer and Autumn
of year 2005 to allow comparisons with a campaign of surface current measurements by high-frequency radars conducted at the
same period. 相似文献
389.
Anna Belehaki Ljiljana Cander Bruno Zolesi Juergen Bremer Christer Juren Iwona Stanisławska Dimitris Dialetis Michael Hatzopoulos 《Acta Geophysica》2007,55(3):398-409
There are two main objectives of the DIAS (European Digital Upper Atmosphere Server) project. First, it establishes a pan-European repository of raw and derived digital data describing the
state of ionospheric part of the upper atmosphere, which is capable of ingesting real-time information and maintaining historical
data collections provided by most operating ionospheric stations in Europe. Second, the DIAS system produces and distributes,
based on the raw data collection, several operational products required by various user groups for ionospheric nowcasting,
prediction and forecasting purposes. The project completed on May 2006 and the DIAS server operates since then continuously.
The basic products that are delivered are real-time and historical ionograms from all DIAS-affiliated ionospheric stations,
frequency plots and maps of the ionosphere over Europe based on the foF2, M(3000)F2, MUF and electron density parameters, as well as long term prediction and short term forecasting up to 24 hour ahead.
The paper describes use of the ionospheric measurements in the DIAS modelling techniques for specification, predict-tion and
forecasting of the ionosphere over the European region, and details the final products available to the DIAS user community. 相似文献
390.