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291.
The vertical transport of contaminants from source areas is employed in many risk assessment models and screening tools in order to estimate the contaminant mass discharge (CMD) into underlying aquifers. The key parameters for estimating CMD are the contaminant source area and concentration, and the vertical water flux, the latter of which depends on the vertical hydraulic conductivity and the vertical hydraulic gradient in the subsurface. This study focuses on advancing the use of the combined membrane interface probe hydraulic profiling tool (MiHPT) to investigate the vertical hydraulic gradient across a clay till overlying a sandy aquifer at a contaminated site in Denmark. Only the HPT is necessary for the estimate of vertical hydraulic gradient. The hydraulic head, clay till thickness, and resulting vertical hydraulic gradients found using the MiHPT compared well with observations from nearby nested wells. The parameter with the largest discrepancy was the thickness of the clay till. The advantage of the MiHPT is its relatively quick depth discrete access to information regarding subsurface permeability, vertical hydraulic gradients and contaminant distribution across a site. In this case study, performance of additional dissipationtests during the HPT log to acquire determination of the vertical hydraulic gradient increased the cost by 3% compared to standard HPT logs.  相似文献   
292.
This study discusses the timing and maximum flood level of the Nedre Glomsjø outburst flood, Norway, based on sediment records retrieved from 15 bog and lake basins located close to the purported maximum flooded level. The sediment records in 12 of the basins consist of a distinct light-coloured silty bed that is correlated to the outburst-flood-deposited ‘Romerike Silt Bed’ identified elsewhere in the region. The silt bed is recorded in basins up to a certain elevation and is absent above this level. The new maximum flood level inferred from the basin sediment records exceeds the established landform-induced palaeostage indicators by 5–10 m. The data indicate a higher maximum flood level and larger inundation area than previously suggested and highlight the importance of acquiring a wide range of geological data when reconstructing palaeofloods. Radiocarbon dates of terrestrial macrofossils found stratigraphically above and below the Romerike Silt Bed suggest that the glacial lake Nedre Glomsjø outburst flood occurred between 10.5 and 10.3 cal. ka BP. The new and well-constrained timing of the outburst flood is beneficial for reconstructing regional deglaciation and provides a precise age for the Romerike Silt Bed chronostratigraphical marker, which is of value for studies in SE Norway and adjacent regions.  相似文献   
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This article explores land-tenure issues faced by Timor-Leste, specifically with reference to customary land, and the significance of mapping in resolving those difficulties. A critical review is undertaken of the pitfalls of Indigenous mapping and applications of Participatory Geographic Information Systems (PGIS) to achieve sensitive and empowering outcomes for customary groups seeking land claims. A methodology for mapping customary land in Timor-Leste is described and an analysis of the author's on-the-ground research is presented. Although the importance of customary institutions for rural land management across Timor-Leste is ascertained, this article does not advance a definitive land rights framework for the country or prescribe national mapping of customary areas. Instead, it argues for a mapping methodology to support land-use decision-making that can make sense of Indigenous knowledge and appropriate cultural practices in rural land-use claims. Identified as crucial in the process is the equal value attributed to evidence presented in myriad forms that may act as key information bridges across epistemological divides and knowledges. PGIS is a potentially important tool for resolving land-use conflicts in rural Timor-Leste when resolution occurs within a formalised institutional framework.  相似文献   
296.
The relationship between expressed attitudes and actual behaviour in the context of sustainable development is complex and difficult to apply in a policy-relevant manner. The household, however, represents a key ‘lens’ for understanding the environmental impact of consumption patterns and for instigating policy designed to change consumer behaviour. This paper assesses the use of a household diary approach as a means of framing and collecting household environmental data, and, critically, as an educational vehicle for bringing about behavioural change by encouraging reflexivity. Evaluating the success of the diary approach at instigating behavioural change, the paper concludes that the diary approach: (1) created awareness about pro-environmental behaviour where there was none; (2) extended existing awareness to a wider range of pro-environmental behaviours and range of household members, and; (3) induced change in pro-environmental behaviour. In particular, the paper argues that current research neglects the potential that participating in the research process may contribute to changing the outlook or behaviour of participants.  相似文献   
297.
We describe a numerical forecast system designed for prediction of physical and biological dynamics of a coastal inlet. It is based on a coastal ocean observatory that was located at Lunenburg Bay, Nova Scotia, Canada. Biological, chemical, optical, and physical measurements were collected from instrumented moorings, weekly sampling and detailed surveys from 2002 through 2007. Here we present a framework for calibration and evaluation of an ecosystem model using data from the summer of 2007. A three-dimensional hydrodynamic model was coupled to a simple biological (Nutrients-Phytoplankton-Detritus) model; a simple model was used so results could be compared directly to observed biological and chemical variables using skill scores as a first step toward data-assimilation modeling. As a complement to this analysis, variability of model output, e.g., the nutrient limitation term, was examined to understand the modeled biological response to the simulated physical environment. Skill scores based on variances in observed and simulated time-series of biological components were also investigated. Coastal upwelling/downwelling simulated through this model has been found to increase modeled biological activity in the bay. Also model skill in reproducing the observed patterns in nutrients and phytoplankton has been increased due to the restoring conditions for biology set up at the open ocean boundaries of the bay.  相似文献   
298.
The wreck of the Rainbow Warrior, a 40-m ship sunk on 12 December 1987 in Matauri Bay (34° 59′ S, 173° 56′ E), Cavalli Islands, northeastern New Zealand, offers an opportunity to investigate the impact of artificial substrate on temperate carbonate sedimentation. Surface sediment samples showed no significant textural or compositional difference between sediments near the wreck and those far from it. The large and diverse carbonate-producing community resident on the wreck (dominated by bryozoans, corals and sponges) has not had a measurable influence on adjacent bottom sediments (dominated by bivalves and barnacles), even after 21 years. It is likely that carbonate production on the Rainbow Warrior is insufficient to leave any sedimentary record over the potential lifetime of the wreck on the seafloor, which informs our understanding of the long-term impacts of shipwrecks (and other artificial substrata) on the local benthic environment in shallow temperate ecosystems.  相似文献   
299.
Louise Waite 《Geoforum》2012,43(2):353-361
The overall aim of this paper is to contribute to debates on the relationships between citizenship and migration in the UK context in the light of recent changes in UK immigration policy. In particular, it focuses on the question of what an increasingly neo-assimilationist state articulation of national belonging means for transnational migrants living in Britain. The paper begins by charting the evolving nature of citizenship conceptualisations in Western neoliberal contexts and illustrates how Britain has responded to this shifting landscape. The context is one of enhanced ‘migration securitization’ wherein the state implies that the integrity of the nation state and its security can only be assured if migration flows and migrants themselves are closely controlled and monitored. This has led to Britain attempting to bolster the formal institution of citizenship (with its attendant rights and responsibilities) and tie it more explicitly to notions of belonging to the nation. Through research with national/regional policy officials and migrant organisations this paper firstly examines the political landscape of citizenship and belonging in Britain as it relates to migrants. Secondly, it draws on research with African transnational migrants in northern England to explore their senses of belonging and ask whether these cohere with the described state discourse or whether their feelings of belonging exist in tension with neo-assimilationist policies designed to promote a core national identity.  相似文献   
300.
Transequatorial Filament Eruption and Its Link to a Coronal Mass Ejection   总被引:3,自引:0,他引:3  
We revisit the Bastille Day flare/CME Event of 2000 July 14, and demonstrate that this flare/CME event is not related to only one single active region (AR). Activation and eruption of a huge transequatorial filament are seen to precede the simultaneous filament eruption and flare in the source active region, NOAA AR 9077, and the full halo-CME in the high corona. Evidence of reconfiguration of large-scale magnetic structures related to the event is illustrated by SOHO EIT and Yohkoh SXT observations, as well as, the reconstructed 3D magnetic lines of force based on the force-free assumption. We suggest that the AR filament in AR9077 was connected to the transequatorial filament. The large-scale magnetic composition related to the transequatorial filament and its sheared magnetic arcade appears to be an essential part of the CME parent magnetic structure. Estimations show that the filament-arcade system has enough magnetic helicity to account for the helicity carried by the related CMEs. In addition, rather global magnetic connectivity, covering almost all the visible range in longitude and a huge span in latitude on the Sun, is implied by the Nancay Radioheliograph (NRH) observations. The analysis of the Bastille Day event suggests that although the triggering of a global CME might take place in an AR, a much larger scale magnetic composition seems to be the source of the ejected magnetic flux, helicity and plasma. The Bastille Day event is the first described example in the literature, in which a transequatorial filament activity appears to play a key role in a global CME. Many tens of halo-CME are found to be associated with transequatorial filaments and their magnetic environment.  相似文献   
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