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551.
With both declining and ageing populations, countries are addressing the threats to their competitiveness by attracting more highly educated workers and by investing in human capital, especially through policies to increase the rates of participation by young people in tertiary education. As the population is still ageing, there are concerns over the affordability of state support for the elderly, their roles in society and the economy. Active and flexible lifestyles extend healthy life expectancy, so extending the length of the working life is increasingly seen as a way to ease the transition to an economy where an ageing population is affordable.Senior academic staff, exemplars of such post-industrial flexibility, have long been accommodated beyond the statutory retirement age. Their benign conditions of work; high private and social returns to experience and knowledge; and their high levels of those skills, labour power and other capacities which do not degenerate with age, combine to prolong the length of their effective working lives. Against this, as in other sectors, redundancies, voluntary severance and other schemes to reduce staffing have encouraged early retirement. Increased demand for higher education has driven changes in the lecturing labour mix, with increasing use of a peripheral workforce of both early career and retiring staff. This has seen semi-retirement within higher education evolving to stretch the period over which withdrawal takes place.In this context, the exploratory work reported here considers the initial responses by employers and trades unions in Scottish Higher Education to the abolition of the default retirement age and the introduction of ‘The Employment Equality (Repeal of Retirement Age Provisions) Regulations 2011’. 相似文献
552.
Kathleen M. Swanson Judith Z. Drexler David H. Schoellhamer Karen M. Thorne Mike L. Casazza Cory T. Overton John C. Callaway John Y. Takekawa 《Estuaries and Coasts》2014,37(2):476-492
Salt marsh faunas are constrained by specific habitat requirements for marsh elevation relative to sea level and tidal range. As sea level rises, changes in relative elevation of the marsh plain will have differing impacts on the availability of habitat for marsh obligate species. The Wetland Accretion Rate Model for Ecosystem Resilience (WARMER) is a 1-D model of elevation that incorporates both biological and physical processes of vertical marsh accretion. Here, we use WARMER to evaluate changes in marsh surface elevation and the impact of these elevation changes on marsh habitat for specific species of concern. Model results were compared to elevation-based habitat criteria developed for marsh vegetation, the endangered California clapper rail (Rallus longirostris obsoletus), and the endangered salt marsh harvest mouse (Reithrodontomys raviventris) to determine the response of marsh habitat for each species to predicted >1-m sea-level rise by 2100. Feedback between vertical accretion mechanisms and elevation reduced the effect of initial elevation in the modeled scenarios. Elevation decreased nonlinearly with larger changes in elevation during the latter half of the century when the rate of sea-level rise increased. Model scenarios indicated that changes in elevation will degrade habitat quality within salt marshes in the San Francisco Estuary, and degradation will accelerate in the latter half of the century as the rate of sea-level rise accelerates. A sensitivity analysis of the model results showed that inorganic sediment accumulation and the rate of sea-level rise had the greatest influence over salt marsh sustainability. 相似文献
553.
Calcrete zones of cemented sands are found repeatedly at beach sites in the Mariana Islands, western Pacific region, with mid‐ to late‐Holocene artifacts and midden sealed within and beneath these layers. Three site‐specific cases demonstrate that the cementation process of the calcareous sand material post‐dated the deposition of artifacts and midden. Archaeological efforts must be prepared for deep excavation through zones of cemented sand. Also, recovery of preserved ancient materials can proceed by excavating large hardened blocks and soaking in light (5%) acid. This knowledge about formation process and recovery technique may prove useful not only in the Mariana Islands but also more broadly in other regions with similar settings. © 2011 Wiley Periodicals, Inc. 相似文献
554.
Bruno O David Mark P Hamer Kevin J Collier Mike D Lake Graham M Surrey Kate McArthur 《新西兰海洋与淡水研究杂志》2013,47(3):177-187
The New Zealand fish fauna contains species that are affected not only by river system connectivity, but also by catchment and local-scale changes in landcover, water quality and habitat quality. Consequently, native fish have potential as multi-scale bioindicators of human pressure on stream ecosystems, yet no standardised, repeatable and scientifically defensible methods currently exist for effectively quantifying their abundance or diversity in New Zealand stream reaches. Here we report on the testing of a back-pack electrofishing method, modified from that used by the United States Environmental Protection Agency, on a wide variety of wadeable stream reaches throughout New Zealand. Seventy-three first- to third-order stream reaches were fished with a single pass over 150–345 m length. Time taken to sample a reach using single-pass electrofishing ranged from 1–8 h. Species accumulation curves indicated that, irrespective of location, continuous sampling of 150 stream metres is required to accurately describe reach-scale fish species richness using this approach. Additional species detection beyond 150 m was rare (<10%) with a single additional species detected at only two out of the 17 reaches sampled beyond this distance. A positive relationship was also evident between species detection and area fished, although stream length rather than area appeared to be the better predictor. The method tested provides a standardised and repeatable approach for regional and/or national reporting on the state of New Zealand's freshwater fish communities and trends in richness and abundance over time. 相似文献
555.
The CrossScale mission will advance our understanding of fundamental plasma processes in collisionless plasmas. It will exploit the excellent natural plasma laboratory provided by the Earth’s magnetosphere and the near-Earth solar wind and, in particular, carry out multi-scale studies that will strongly complement plasma studies in ground-based laboratories. Previous studies of collisionless plasmas in space environments across the solar system have shown the ubiquitous nature of suprathermal particles and that these particles exhibit a power-law energy spectrum. In this paper we discuss the great significance of these suprathermal particles for CrossScale studies. We show that the presence of these particles is a natural consequence of the collisionless regime as they can propagate across the heliosphere with little spectral change and are not thermalised by collisions. They are a key indicator of the non-equilibrium nature of collisionless plasmas and an important source of free energy that can drive plasma processes. We discuss how these suprathermal particles influence the overall properties of the plasma. In particular, the energy distribution of particles follows a Kappa, rather than Maxwellian, distribution and thus the plasma does not have a single thermodynamic temperature. We also discuss the importance of the suprathermal tail as a tool to diagnose the processes responsible for particle energisation in collisionless plasmas. Such energisation is a common feature in collisionless plasmas, especially in terms of the primary science targets for CrossScale: reconnection, shocks and turbulence. Finally we also touch on the value of using CrossScale studies to provide ground truth measurements for a number of astrophysical techniques that exploit the effects of energetic electrons in the distant universe. Throughout the paper, we stress that suprathermal (30 keV-1 MeV) measurements are essential to fully characterise particle distributions. We show that such measurements will benefit greatly from the improved spatial and temporal resolution (compared to Cluster) that is proposed for the HEP instrument on CrossScale. 相似文献
556.
557.
The two-dimensional variably-saturated numerical model HYDRUS-2D, previously calibrated to recharge events from an infiltration basin, was used to predict water-table mounding under hypothetical basin design scenarios, and the primary factors that affect water-table mounding were evaluated. Infiltration basins are often utilized in urban environments to recharge stormwater to the aquifer. As a result of localized recharge beneath these basins, mound formation may reduce the thickness of the unsaturated zone available to filter pollutants and may reduce the infiltration rate of the basin. Understanding the effects of various physical factors on water-table mound formation is important for infiltration basin siting. For sandy loam and loamy sand subsurface materials, mound heights increased as the thickness of both the unsaturated and saturated zones decreased. Mound heights increased as the initial soil moisture, basin size and ponding depth increased. A thin sedimentation layer on the basin floor delayed mound formation, but only slightly decreased the maximum mound height. This analysis could be used in future selection of infiltration basin locations; however, the analysis is limited to conditions that represent only a select range of basin design conditions and parameters typical of a glacial till environment in Wisconsin, USA. 相似文献
558.
559.
Tim Woollings Brian Hoskins Mike Blackburn David Hassell Kevin Hodges 《Climate Dynamics》2010,35(2-3):341-353
A high resolution regional atmosphere model is used to investigate the sensitivity of the North Atlantic storm track to the spatial and temporal resolution of the sea surface temperature (SST) data used as a lower boundary condition. The model is run over an unusually large domain covering all of the North Atlantic and Europe, and is shown to produce a very good simulation of the observed storm track structure. The model is forced at the lateral boundaries with 15–20 years of data from the ERA-40 reanalysis, and at the lower boundary by SST data of differing resolution. The impacts of increasing spatial and temporal resolution are assessed separately, and in both cases increasing the resolution leads to subtle, but significant changes in the storm track. In some, but not all cases these changes act to reduce the small storm track biases seen in the model when it is forced with low-resolution SSTs. In addition there are several clear mesoscale responses to increased spatial SST resolution, with surface heat fluxes and convective precipitation increasing by 10–20% along the Gulf Stream SST gradient. 相似文献
560.
Mike T. Carson 《Geoarchaeology》2012,27(5):385-409
The royal court of the Kamehameha Dynasty in Kawaihae, Hawai‘i Island, presents an unequalled opportunity to examine the ethnohistoric rendering of a cultural landscape, in comparison to the geoarchaeological record of physical transformation of this same landscape. Beneath the surface, earlier occupation layers predate the historic royal precinct of the A.D. 1790s through 1820s. Drawing on results of 19 controlled excavations, point‐specific cultural activities are situated within the last several centuries of natural terrain formation, beginning A.D. 1200–1400 and ending A.D. 1830–present. Geoarchaeological excavations provide the means to place the stratified cultural deposits, occupational horizons, and activity areas in the context of depositional history, environmental transformation, and changing social circumstances in a continuous sequence. The material‐based geoarchaeological landscape chronology and the ethnohistorically defined cultural landscape are combined for a more holistic view than either one could provide independently. 相似文献