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271.
The prevailing view suggests that the Eemian interglacial on the European Plain was characterized by largely negligible geomorphic activity beyond the coastal areas. However, systematic geomorphological studies are sparse. Here we present a detailed reconstruction of Eemian to Early Weichselian landscape evolution in the vicinity of a small fingerlake on the northern margin of the Salzwedel Palaeolake in Lower Saxony (Germany). We apply a combination of seismics, sediment coring, pollen analysis and luminescence dating on a complex sequence of colluvial, paludal and lacustrine sediments. Results suggest two pronounced phases of geomorphic activity, directly before the onset and at the end of the Eemian period, with an intermediate period of pronounced landscape stability. The dynamic phases were largely driven by incomplete vegetation cover, but likely accentuated by fluvial incision in the neighbouring Elbe Valley. Furthermore, we discovered Neanderthal occupation at the lakeshore during Eemian pollen zone (PZ) E IV, which is chronologically in line with other known Eemian sites of central Europe. Our highly-resolved spatio-temporal data substantially contribute to the understanding of climate-induced geomorphic processes throughout and directly after the last interglacial period. It helps unraveling the landscape dynamics between the coastal areas to the north and the loess belt to the south.  相似文献   
272.
Reconstructing ancient topography through erosion modelling   总被引:1,自引:1,他引:1  
One of the main aims of geomorphology is to understand how geomorphic processes change topography over long time scales. Over the last decades several landscape evolution models have been developed in order to study this question. However, evaluation of such models has often been very limited due to the lack of necessary field data. In this study we present a topography based hillslope erosion and deposition model that is based on the WATEM/SEDEM model structure and works on a millennial time scale. Soil erosion, transport and deposition are calculated using slope and unit contributing area. The topography is iteratively rejuvenated by taking into account modelled erosion and deposition rates, thereby simulating topographic development backwards in time. A first attempt has been made to spatially evaluate the model, using detailed estimates for historical soil erosion and sediment deposition volumes, obtained from an augering campaign in a small catchment in the Belgian Loess Belt. The results show that the model can simulate realistic soil redistribution patterns. However, further research is necessary in order to deal with artificial flaws that cause routing problems and significantly influence results. Common problems and issues related to this type of backward modelling are also discussed.  相似文献   
273.
aau am ¶rt;au aammuu nmu ¶rt;u u ¶rt;um uu u a a nmu ma,¶rt; umum a. ¶rt; n¶rt;m au a, a nuu ¶rt;auu nmu. uu u uuu nam. a ¶rt;u u ¶rt;auu u n¶rt;uu a u a. ¶rt; mu ¶rt; aa num uu a¶rt;u.  相似文献   
274.
Abstract— Sample preparation is always a critical step in the study of micrometer‐sized astromaterials available for study in the laboratory, whether their subsequent analysis is by electron microscopy or secondary ion mass spectrometry. A focused beam of gallium ions has been used to prepare electron transparent sections from an interplanetary dust particle (IDP), as part of an integrated analysis protocol to maximize the mineralogical, elemental, isotopic, and spectroscopic information extracted from one individual particle. In addition, focused ion beam (FIB) techniques have been employed to extract cometary residue preserved on the rims and walls of microcraters in 1100 series aluminum foils that were wrapped around the sample tray assembly on the Stardust cometary sample collector. Non‐ideal surface geometries and inconveniently located regions of interest required creative solutions. These include support pillar construction and relocation of a significant portion of sample to access a region of interest. Serial sectioning, in a manner similar to ultramicrotomy, is a significant development and further demonstrates the unique capabilities of focused ion beam microscopy for sample preparation of astromaterials.  相似文献   
275.
The geodynamic interpretation of the results of GPS observations among the permanently operating stations which establish the frame for defining and conserving the coordinate system and simultaneously for describing the fundamental tendencies of dynamics in the area represented by them, should be deprived of the effects of geodynamic phenomena, which can be either periodic or short-term (even non-periodic) so that secular changes may be found. Some of these influences are included in scientific processing software, others have to be modelled later. The purpose of this project is to determine the influences of the indirect effect of ocean tides and the direct deformational effect of the atmosphere on the results of GPS observations, performed at stations Pecný (Czech Republic), Wettzell (FRG) and Graz (Austria), and also for the GPS stations of the Central Europe Regional Geodynamic Project (CERGOP) in the region of Central and East Europe. On the basis of analyses and results it is possible to claim that at the present accuracy of GPS observations the influence of ocean loading and atmospheric pressure effects for geodynamic campaigns in the region of the Czech Republic is negligible. For campaigns in larger regions (i.e. Central Europe) atmospheric corrections will have to be applied to height differences. These corrections, however, due to their periodicity have negligible influence on secular changes.  相似文献   
276.
277.
The cod stocks in the Baltic Sea are important not only for fisheries but for the entire ecosystem utilized by numerous stakeholders around the coast. All such activities have economic values. In this note the economics of the Swedish Baltic Sea cod fishery is estimated in relation to the sector's interaction with other users of the Baltic Sea ecosystem. The results show a negative resource rent for the fishery, € −5 million without public expenses (subsidies and administrative costs), and € −13 million including public expenses. The interactions between the fisheries and tourism, seal population, carbon dioxide emissions, recreational fishing, and discards are discussed, and when monetary estimates are available these are related to the estimated resource rent.  相似文献   
278.
The best strategy to cope with natural hazards is the integral risk management, which involves all participants, decides on the basis of risks and also accepts a residual risk. Therefore, a substantial risk dialogue is essential not only to encourage self-responsibility. Even if throughout the Alpine perimeter this is accepted by the administration and the experts, the difficulties lie in the detail on the way to a full implementation of the effective risk management into practice. Therefore, a series of expert hearings and workshops was carried out in Bavaria to highlight the status of risk dialogue and point out the need for further development. In the beginning, an expert hearing dealt with the status of torrential risk management and worked out recommendations, focusing on the phases of reconstruction, preparation and prevention. On this basis, a practitioner workshop developed solution concepts for two case studies regarding all elements of the integral risk management. One of these was further regarded in a final workshop together with the municipality to encourage risk awareness, risk dialogue and to estimate the benefit of the measures. The activities and the results are described and summarized in the following article.  相似文献   
279.
While hotspots of alcohol-related incidents have been associated with alcohol outlet density, few studies have considered other environmental factors. We aimed to characterise the environment of hotspots outside of outlet density areas in Amsterdam. Using geographical information systems, we identified hotspots of alcohol-related health incidents outside of outlet density areas based on the registry of alcohol related ambulance attendances. While quantitative data and methods were used to analyse victim profiles (including age, sex and home address) and temporal profiles (time of incident), we combined quantitative and qualitative information to develop environmental profiles of these hotspots. We identified 11 hotspots with 242 incidents outside outlet density areas. Results indicate substantial differences between incidents in these hotspots and incidents in high outlet density areas. Victims in these hotspots are older, more often male and live closer to the incident location compared to victims in high outlet density hotspots. Incidents are less likely to take place during the night and at weekends. In-depth analysis of four hotspots showed different combinations of contributing environmental factors, including (a) public parks bordering deprived neighbourhoods, (b) dance event facilities close to a traffic black spot, and (c) residential services for disadvantaged groups near ‘hang-outs’. The study shows that hotspots of alcohol-related incidents can arise outside outlet density areas at locations where several other environmental factors cluster, particularly in more deprived areas. Such hotspots can be addressed in urban planning and urban design.  相似文献   
280.
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