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321.
Involvement in scientifically structured habitat monitoring is a relatively new concept to the peoples of Torres Strait. The approach we used was to focus on awareness, and to build the capacity of groups to participate using Seagrass-Watch as the vehicle to provide education and training in monitoring marine ecosystems. The project successfully delivered quality scientifically rigorous baseline information on the seasonality of seagrasses in the Torres Strait—a first for this region.  相似文献   
322.
Recent changes in local food supply systems have attracted substantial research interest, but little consideration has been paid to exactly where they occur. This article combines data from three studies to compare local food system development in England, Wales, Scotland and Ireland using a single index of food relocalisation, thereby exploring the usefulness of the Index across different social and political contexts. Four diagnostic indicators suggest that local food systems in the south west of Ireland and Britain are particularly well developed. The Index itself is a useful tool for making international comparisons, being easy to replicate and allowing the integration of different data sets. Perhaps its greatest utility is that it opens up new avenues for further research.  相似文献   
323.
The Angkor basin of Cambodia, the site of the great Angkor temple complex, has experienced explosive tourism growth since the 1993 onset of national political stability and renewed international investment, which in turn has driven increasing demand for water, wood, and biomass fuel, and rapid and extensive land-use and land-cover change. We use multi-temporal Landsat imagery (1989–2005) to describe the rate and extent of land-cover change throughout the Angkor basin. While 50% of the landscape remained in rice agriculture it is notable that a larger proportion of the area was deforested (23.4%) than experienced forest regrowth (4.9%). Most forest loss occurred between the Angkor temple complex and Phnom Kulen National Park, and was due in part to charcoal production to serve the tourist industry, and also conversion to permanent agriculture. The small area of forest increase was concentrated along the eastern boundary of the main Angkor complex. The interplay among global (tourism, climate), regional (national policies, large-river management), and local (construction and agriculture, energy and water sources to support the tourism industry) factors drives a distinctive but complex pattern of land-use and land-cover change.  相似文献   
324.
The Konya plain in south central Anatolia, Turkey, which is now largely dry, was occupied around the time of the Last Glacial Maximum by a fresh-oligosaline lake covering more than 4000 km2. Sediment cores from three residual water bodies (Pinarbai, Akgöl and Süleymanhaci) within the larger Pleistocene lake basin, have been analysed using a multidisciplinary approach. The sediment sequences are dated as spanning the last 50 Ka years, although breaks in sedimentation mean that there is only partial chronological overlap between them. Carbon and oxygen isotope analyses on lacustrine carbonate from the three cores give contrasting isotope profiles which reflect the different ages and independent hydrological behaviour of different sub-basins through the late Quaternary. Distinguishing changes that are regional from local effects is aided by modern isotope hydrology studies and by comparing the carbonate 13C and 18O values to diatom and other analyses undertaken on the same cores.  相似文献   
325.
326.
Local policies can play an important role in establishing a context that shapes vulnerability and influences subsequent recovery of lifelines under the natural hazards of extreme wind and seismic events. External factors, such as access availability, have long been known to influence the rate of restoration of utility systems following blackouts. Thus, since system performance takes place within a socio-technical-political context, it can be anticipated that selected local policies may also influence either the geographic extent of damage or the rate of restoration or both. This project empirically validates the assumption that selected local non-design policies establish a context that significantly (measurably) influences system functionality in terms of spatial extent and duration of outage.  相似文献   
327.
Microwave modulation by swell waves and its relation to microbreaking waves were investigated in an ocean experiment. Simultaneous collocated microwave and infrared (IR) measurements of wind waves and swell on the ocean were made. The normalized radar cross section sigma0 and the skin temperature T skin were both modulated by the swell, but with differing phases. In general, sigma0 maxima occurred on the front face, whereas T skin maxima occurred on the rear face of the swell. Infrared imagery has shown that swell-induced microbreaking occurred at or near the swell crest and that the resulting warm wakes occurred on the rear face of the wave. When tilt and range modulations are taken into account, the location of microbreaking also accounts for the maximum of sigma0 occurring on the front face of the swell. Thus, microbreaking waves generated near the crest of low-amplitude swell can produce microwave and IR signatures with the observed phase. The relationship between microwave and IR signals was further emphasized by comparing microwave Doppler spectra with simultaneous IR and visible images of the sea surface from the same location. When small and microscale breaking waves were present, Doppler spectra exhibited characteristics that are similar to those from whitecaps, having peaks with large Doppler offsets and polarization ratios near unity. When no microbreakers were present, Doppler offsets and polarization ratios were much smaller in accordance with a composite surface scattering theory.  相似文献   
328.
This modeling study addresses the potential impacts of climate change and changing climate variability due to increased atmospheric CO2 concentration on soybean (Glycine max (L.) Merrill) yields in theMidwestern Great Lakes Region. Nine representative farm locations and six future climate scenarios were analyzed using the crop growth model SOYGRO. Under the future climate scenarios earlierplanting dates produced soybean yield increases of up to 120% above current levels in the central and northern areas of the study region. In the southern areas, comparatively small increases (0.1 to 20%) and small decreases (–0.1 to–25%) in yield are found. The decreases in yield occurred under the Hadley Center greenhouse gas run (HadCM2-GHG), representing a greater warming, and the doubled climate variability scenario – a more extreme and variableclimate. Optimum planting dates become later in the southern regions. CO2fertilization effects (555 ppmv) are found to be significant for soybean, increasing yields around 20% under future climate scenarios.For the study region as a whole the climate changes modeled in this research would have an overall beneficial effect, with mean soybean yield increases of 40% over current levels.  相似文献   
329.
The role of atmospheric general circulation model (AGCM) horizontal resolution in representing the global energy budget and hydrological cycle is assessed, with the aim of improving the understanding of model uncertainties in simulating the hydrological cycle. We use two AGCMs from the UK Met Office Hadley Centre: HadGEM1-A at resolutions ranging from 270 to 60 km, and HadGEM3-A ranging from 135 to 25 km. The models exhibit a stable hydrological cycle, although too intense compared to reanalyses and observations. This over-intensity is explained by excess surface shortwave radiation, a common error in general circulation models (GCMs). This result is insensitive to resolution. However, as resolution is increased, precipitation decreases over the ocean and increases over the land. This is associated with an increase in atmospheric moisture transport from ocean to land, which changes the partitioning of moisture fluxes that contribute to precipitation over land from less local to more non-local moisture sources. The results start to converge at 60-km resolution, which underlines the excessive reliance of the mean hydrological cycle on physical parametrization (local unresolved processes) versus model dynamics (large-scale resolved processes) in coarser HadGEM1 and HadGEM3 GCMs. This finding may be valid for other GCMs, showing the necessity to analyze other chains of GCMs that may become available in the future with such a range of horizontal resolutions. Our finding supports the hypothesis that heterogeneity in model parametrization is one of the underlying causes of model disagreement in the Coupled Model Intercomparison Project (CMIP) exercises.  相似文献   
330.
In recent years, Australian governments and fishing industry associations have developed guiding principles aimed at reducing the impact of fishing on non-target species and the benthos and increasing community awareness of their efforts. To determine whether they reduced seal entanglement in lost fishing gear and other marine debris, we analysed Australian sea lion and New Zealand fur seal entanglement data collected from Kangaroo Island, South Australia. Contrary to our expectations, we found that entanglement rates did not decrease in recent years. The Australian sea lion entanglement rate (1.3% in 2002) and the New Zealand fur seal entanglement rate (0.9% in 2002) are the third and fourth highest reported for any seal species. Australian sea lions were most frequently entangled in monofilament gillnet that most likely originated from the shark fishery, which operates in the region where sea lions forage--south and east of Kangaroo Island. In contrast, New Zealand fur seals were most commonly entangled in loops of packing tape and trawl net fragments suspected to be from regional rock lobster and trawl fisheries. Based on recent entanglement studies, we estimate that 1478 seals die from entanglement each year in Australia. We discuss remedies such as education programs and government incentives that may reduce entanglements.  相似文献   
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