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71.
Occupational transitions in three coastal villages in Central Java, Indonesia, in the context of sea level rise: a case study 总被引:1,自引:0,他引:1
The transition from one system to another as a mechanism of adaptation to an external disturbance is widely discussed in terms of ‘regime shifts’ in resilience research. But occupational transitions by communities due to coastal hazards such as coastal erosion and strong waves have not been studied in depth from a systems perspective. Such a perspective can contribute towards a better understanding of the process and pattern behind transformation among coastal societies. The present case study of coastal occupational communities in Central Java province, Indonesia, includes fishers, brackish pond farmers and labourers. It investigates the historical occupational transitions and the factors that drive them. The study draws on Participatory Rural Appraisal exercises such as historical timeline analysis and participatory discussions along with a socio-economic survey to study the factors and processes that led these communities to transitional pathways. Historical narratives of the community reveal the significance and influence of livelihood capitals such as social, human, financial, physical and natural capital in the transitions. Through the ‘Marble and Cup’ conceptual framework of the systems transitions, the irreversibility of occupational transitions due to the destruction of natural assets is outlined. This depicts a multi-locale and one-dimensional transition to a singular occupational mode (essentially labourers) in the face of a disturbance like sea level rise, necessitating transformation and building of the livelihood capitals across geographical scales. 相似文献
72.
Philip K. Thornton Peter G. Jones Gopal Alagarswamy Jeff Andresen 《Global Environmental Change》2009,19(1):54-65
There is general consensus that the impacts of climate change on agriculture will add significantly to the development challenges of ensuring food security and reducing poverty, particularly in Africa. While these changes will influence agriculture at a broad scale, regional or country-level assessments can miss critical detail. We use high-resolution methods to generate characteristic daily weather data for a combination of different future emission scenarios and climate models to drive detailed simulation models of the maize and bean crops. For the East African region, there is considerable spatial and temporal variation in this crop response. We evaluate the response of maize and beans to a changing climate, as a prelude to detailed targeting of options that can help smallholder households adapt. The results argue strongly against the idea of large, spatially contiguous development domains for identifying and implementing adaptation options, particularly in regions with large variations in topography and current average temperatures. Rather, they underline the importance of localised, community-based efforts to increase local adaptive capacity, take advantage of changes that may lead to increased crop and livestock productivity where this is possible, and to buffer the situations where increased stresses are likely. 相似文献
73.
Richard T. Gill Steven F. Thornton Michael J. Harbottle Jonathan W.N. Smith 《Ground Water Monitoring & Remediation》2015,35(3):46-56
This study investigates and quantifies the influence of physical heterogeneity in granular porous media, represented by materials with different hydraulic conductivity, on the migration of nitrate, used as an amendment to enhance bioremediation, under an electric field. Laboratory experiments were conducted in a bench‐scale test cell under a low applied direct current using glass bead and clay mixes and synthetic groundwater to represent ideal conditions. The experiments included bromide tracer tests in homogeneous settings to deduce controls on electrokinetic transport of inorganic solutes in the different materials, and comparison of nitrate migration under homogeneous and heterogeneous scenarios. The results indicate that physical heterogeneity of subsurface materials, represented by a contrast between a higher‐hydraulic conductivity and lower‐hydraulic conductivity material normal to the direction of the applied electric field exerts the following controls on nitrate migration: (1) a spatial change in nitrate migration rate due to changes in effective ionic mobility and subsequent accumulation of nitrate at the interface between these materials; and (2) a spatial change in the voltage gradient distribution across the hydraulic conductivity contrast, due to the inverse relationship with effective ionic mobility. These factors will contribute to higher mass transport of nitrate through low hydraulic conductivity zones in heterogeneous porous media, relative to homogeneous host materials. Overall electrokinetic migration of amendments such as nitrate can be increased in heterogeneous granular porous media to enhance the in situ bioremediation of organic contaminants present in low hydraulic conductivity zones. 相似文献
74.
S. M. Dunn S. I. Vinogradoff G. J. P. Thornton J. R. Bacon M. C. Graham J. G. Farmer 《水文研究》2006,20(14):3049-3068
Hydrological budgets and flow pathways have been quantified for a small upland catchment (1.76 km2) in the northeast of Scotland. Water balance calculations for four subcatchments identified spatial variability within the catchment, with an estimated runoff enhancement of up to 25% for the upper western area, compared with the rest of the catchment. Data from spatial hydrochemical sampling, over a range of flow conditions, were used to identify the principal hillslope runoff mechanisms within the catchment. A hydrochemical mixing analysis revealed that runoff emerging from springs in various locations of the hillslope accounted for a significant proportion of flow in the streams, even during storm events. A hydrological model of the catchment was calibrated using the calculated stream flows for four locations, together with results from the mixing analysis for different time points. The calibrated model was used to predict the temporal variability in contributions to stream flow from the hillslope springs and soil water flows. The overall split ranged from 57%:43% spring water:soil water in the upper eastern subcatchment, to 76%:24% in the upper western subcatchment. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
75.
Linden Ashcroft Rob Allan Howard Bridgman Joëlle Gergis Christa Pudmenzky Ken Thornton 《大气科学进展》2016,33(12):1323-1324
正1.Introduction Recovering historical instrumental climate data is crucial for identifying long-term climate variability and change,putting present climate into context and constraining future climate projections(Brunet and Jones,2011).In other words,to understand the future,we need to improve our understand- 相似文献
76.
A review of some unique aspects of the limnology of shallow Southern African man-made lakes 总被引:1,自引:0,他引:1
J. A. Thornton Dr. 《GeoJournal》1987,14(3):339-352
Large numbers of man-made lakes occur throughout S Africa. Although primarily designed for specific water supply purposes, most of these lakes fulfill a multipurpose role. The need for such large numbers of reservoirs is related to vagaries in rainfall and runoff; these uncertainties have led to the development of a philosophy of conserving water quantity, which has created some unusual limnological conditions. Examination of the hydrography and limnology of 64 S African impoundments reveals that both basin morphometry and water retention times are affected by natural (drought/flood) and artificial (drawdown) factors which, in turn, affect the hydrodynamics of the lakes, whilst the introduction of treated effluents as a water conservation measure gives rise to a large percentage of enriched lakes having extremely high productivity. 相似文献
77.
Scott E. Thornton 《Geo-Marine Letters》1986,6(1):15-19
Holocene mass flow processes produce distinctive sedimentary structures in this silled, anoxic basin characterized by high
sedimentation rates of fine-grained fill. Mud flow deposits possess a 0899 1444 V
3 diagnostic vertical sequence of structures on the lower slope. Basin floor turbidites possess a variety of bed set combinations
of: 1) finely laminated layers, 2) graded silt and clay layers, and 3) ungraded, massive silts and clays with floating sand
grains. Massive, ungraded flood-derived suspensate deposits can be distinguished from turbidites. Turbidites and suspensate
deposits constitute 30% of the sampled sediment column. Varve counting of the remaining 70% provides frequencies of turbidite
and flood suspensate layer deposition. 相似文献
78.
79.
Rebecca Bartlett Simon H. Bottrell Karen Sinclair Steve Thornton Ian D. Fielding Dave Hatfield 《水文研究》2010,24(6):726-735
Depth profiles of solute chemistry and sulfate isotopic compositions are presented for groundwater and pore water in a sequence of Quaternary glacial outwash sediments. Sand units show evidence for hydraulic connection to the surface and thus modern sources of solutes. Finer‐grained sediments show a general pattern of increasing solute concentrations with depth, with sulfate derived from ancient rainwater and pyrite oxidation in the soil/drift. In these sediments sulfate has undergone bacterial sulfate reduction (BSR) to produce biogenic sulfide. In clay sediments, with d10 ≤ 1·6 µm, high concentrations of sulfate and acetate now co‐exist, implying that BSR is inhibited. The correlation with smaller sediment grain size indicates that this is due to pore size exclusion of the sulfate reducing bacteria. Mechanical restriction of microbial function thus provides a fundamental limitation on microbial respiration in buried clay‐rich sediments, which acts as a control on the chemical evolution of their pore waters. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献