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171.
172.
Heat Wave Hazards: An Overview of Heat Wave Impacts in Canada 总被引:1,自引:2,他引:1
Extreme heat events are natural hazards affecting Canada and many other regions of the world. This paper presents an overview of the issues involved in defining heat waves and harmful hot weather events, followed by a spatial and historical overview of heat waves across Canada, and an assessment of heat wave adaptation potential in selected cities. The Prairies, Southern Ontario, and areas in the St. Lawrence River Valley of both Ontario and Quebec demonstrate the highest temperatures and most frequent occurrences of heat waves, with minimal effects in the North, Pacific Coast, and Maritimes. Montreal frequently experiences extreme heat, and based on its low air conditioning rates and older, high-density housing, it demonstrates limited potential for adaptation to heat events. A scientific assessment was done to identify the effects of heat waves on various sectors of Canadian life including agriculture, livestock, fisheries, construction, transportation, utilities, the environment, and human health. Heat stress has been linked to excess human mortality and illness, violent behaviour, drought, forest fires, tornadoes, decreased agricultural and livestock productivity, construction and transportation difficulties, and reduced electrical power supply. Despite limited research on heat waves in Canada, this study demonstrates that the impacts of heat are profound and far-reaching. 相似文献
173.
Juanita Sundberg 《The Professional geographer》2003,55(2):180-190
Given the importance of fieldwork in Latin Americanist geography, it is intriguing to note the absence of a dialogue about the politics of fieldwork within the subdiscipline. Drawing from feminist theories about the production of knowledge, this article suggests that the silence about fieldwork is rooted in masculinist epistemologies that predominate in Latin Americanist geography. After analyzing the epistemological and pedagogical implications of masculinism, I argue for increased attention to the nexus of power and knowledge and in particular, to how the researcher's geographic location, social status, race, and gender fundamentally shape the questions asked, the data collected, and the interpretation of the data. Dialogue about these issues in our teaching and writing not only will better prepare students for fieldwork, but also has the potential to foster research that subverts rather than reproduces power inequalities. 相似文献
174.
In this paper, we show that supercritical fluids have a greater significance in the generation of pegmatites,and for ore-forming processes related to granites than is usually assumed. We show that the supercritical melt or fluid is a silicate phase in which volatiles; principally H_2O are completely miscible in all proportions at magmatic temperatures and pressures. This phase evolves from felsic melts and changes into hydrothermal fluids, and its unique properties are particularly important in sequestering and concentrating low abundance elements, such as metals. In our past research, we have focused on processes observed at upper crustal levels, however extensive work by us and other researchers have demonstrated that supercritical melt/fluids should be abundant in melting zones at deep-crustal levels too. We propose that these fluids may provide a connecting link between lower and upper crustal magmas,and a highly efficient transport mechanism for usually melt incompatible elements. In this paper, we explore the unique features of this fluid which allow the partitioning of variouselements and compounds, potentially up to extreme levels,and may explain various features both of mineralization and the magmas that produced them. 相似文献
175.
While the geopolitical legacies of the World War I peace negotiations are widely recognized, this article examines the often overlooked connection between the WWI Paris Peace Conference's spatial and geopolitical logics and contemporary refugee‐border dynamics. We argue that the spatial and geopolitical logics that framed the WWI Paris Peace Conference—the creation of new states, the propagation of the Western ideal of bounded sovereign states, the nationalist goals of self‐determination and homogeneous ethnic nations, and the establishment of a system of international governance—continue to impact refugee‐border dynamics and “crises” today. The categories, ideals, and practices of the international refugee regime that emerged over the last one‐hundred years stem in great part from these logics. In this paper, we urge critical contemplation about how these foundations—including the establishment of the post of High Commissioner for Refugees in 1921, the resultant Nansen Passports, the post‐WWI minority treaties, and lastly the 1933 Convention Relating to the International Status of Refugees—connect to contemporary human (im)mobility and border violence. We also introduce the articles in this special issue and highlight key themes and future directions for research in critical migration studies. 相似文献
176.
Zoltn Vci Carl B. Agee Christopher D. K. Herd Erin Walton Oliver Tschauner Karen Ziegler Vitali B. Prakapenka Eran Greenberg Sylvia Monique‐Thomas 《Meteoritics & planetary science》2020,55(5):1011-1030
Hydrous alteration of olivine macrocrysts in a Martian olivine phyric basalt, NWA 10416, and a terrestrial basalt from southern Colorado are examined using SEM, EPMA, TEM, and µXRD techniques. The olivines in the meteorite contain linear nanotubes of hydrous material, amorphous areas, and fluid dissolution textures quite distinct from alteration identified in other Martian meteorites. Instead, they bear resemblance to terrestrial deuteric alteration features. The presence of the hydrous alteration phase Mg‐laihunite within the olivines has been confirmed by µXRD analysis. The cores of the olivines in both Martian and terrestrial samples are overgrown by unaltered rims whose compositions match those of a separate population of groundmass olivines, suggesting that the core olivines are xenocrysts whose alteration preceded crystallization of the groundmass. The terrestrial sample is linked to deep crustal metasomatism and the “ignimbrite flare‐up” of the Oligocene epoch. The comparison of the two samples suggests the existence of an analogous relatively water‐rich magmatic reservoir on Mars. 相似文献
177.
Marie Maar Karsten Bolding Jens Kjerulf Petersen Jrgen L.S. Hansen Karen Timmermann 《Journal of Sea Research》2009,62(2-3):159
The development of off-shore wind farms along the coastline of north-west Europe is rapidly increasing; it is therefore important to study how this will affect the marine environment. The present study modelled the growth and feed-backs of blue mussels in natural beds and on turbine foundations in an off-shore wind farm (OWF) located in a shallow coastal ecosystem by coupling a dynamic energy budget (DEB) model to a small-scale 3D hydrodynamic–biogeochemical model. The model results showed that blue mussels located higher up in the water column on turbine pillars achieved a 7–18 times higher biomass than those located on the scour protection because the former experience an enhanced advective food supply. Secondly, the high biomasses of blue mussels on foundations created local ‘hot spots’ of biological activity and changed ecosystem dynamics due to their feed-backs e.g. ingestion of microplankton and copepods, excretion of ammonium and egestion of faecal pellets. The model results were supported by field measurements around foundations of Chl a concentrations and biomasses of the fauna community. Our study emphasised that OWFs seem to be particularly favourable for blue mussels in the western Baltic Sea and that the functioning of the OWFs as artificial reef ecosystems depends upon how the blue mussels interact with their local pelagic and benthic environment. 相似文献
178.
The effect of regional ocean loading on predicted rates of crustal uplift and gravitational change due to glacial isostatic adjustment (GIA) is determined for Antarctica. The effect is found to be significant for the ICE-3G and ICE-5G loading histories (up to ?8 mm/year and ?3 mm/year change in uplift rate and ?3 cm/year and ?1 cm/year equivalent water height change (EWHC) of surface mass, respectively). The effect is smaller (+1 mm/year; +0.25 cm/year) for the IJ05 loading history. The impact of ocean loading on the rate of change of the long-wavelength zonal harmonics of the Earth’s gravitational field is also significantly smaller for IJ05 than ICE-3G. A simple analytical formula is derived that is accurate to about 3% in a root-mean-square sense that relates predicted or observed gravitational change at the surface of the Earth (r = a) to the EWHC. A fundamental difference in the definition of the load histories accounts for the differing sensitivities to ocean loading. IJ05 defines its surface load history relative to the present-day surface load, rather than specifying an absolute loading history, and thus implicitly approximates the temporal and spatial mass exchange between grounded ice and open ocean. In contrast, ICE-3G and ICE-5G specify an absolute load history and explicit regional ocean loading substantially perturbs predicted GIA rates. Conclusions of previous studies that used IJ05 predictions without ocean loading are relatively robust. 相似文献
179.
David Tai-Wai Hui Karen Kit-Ying Shum Ji Chen Shyh-Chin Chen Jack Ritchie John O. Roads 《Natural Hazards》2007,42(1):193-207
Seasonal climate forecasts are one of the most promising tools for providing early warnings for natural hazards such as floods
and droughts. Using two case studies, this paper documents the skill of a regional climate model in the seasonal forecasting
of below normal rainfall in southern China during the rainy seasons of July–August–September 2003 and April–May–June 2004.
The regional model is based on the Regional Spectral Model of the National Centers for Environmental Prediction of the United
States. It is the first time that the model has been applied to a region dominated by the East Asian Monsoon.
The article shows that the regional climate model, when being forced by reasonably good forecasts from a global model, can
generate useful seasonal rainfall forecasts for the region, where it is dominated by the East Asia monsoon. The spatial details
of the dry conditions obtained from the regional climate model forecast are also found to be comparable with the observed
distribution. 相似文献
180.
Trickle Down? Private sector participation and the pro-poor water supply debate in Jakarta, Indonesia 总被引:1,自引:0,他引:1
Karen Bakker 《Geoforum》2007,38(5):855-868
Private sector partnerships (PSPs) have been increasingly advocated as an instrument of ‘pro-poor’ water supply policies. This article examines the performance of the private sector with respect to network connections for poor households in Jakarta, Indonesia, drawing on three sources: data collected through a household survey of poor households in six Jakarta neighbourhoods in 2005; data provided by the two private concessionaires and the Jakarta municipal government; and interviews with water supply managers, government officials, and NGO representatives in 2001 and 2005. The analysis concludes that the Jakarta PSP contract has not been pro-poor: new connections were preferentially targeted at middle and upper-income households over the period 1998-2005, and the numbers of new connections have been lower than the original targets. The paper argues that the failure to connect the poor is not solely attributable to the private operators, and identifies disincentives to provide individual network connections to poor households on the part of the municipality, the private concessionaires and poor households. The paper concludes by questioning the long-term ability of private sector operators to supply water to the poor. 相似文献