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91.
Glaciers show a sensitive and rapid response to climate shifts. Associated changes in ice extent drive variations in the production of rock flour, the suspended product of glacial erosion. These glacigenic sediments may accumulate in downstream lakes, continuously recording glacier history. Consequently, the lacustrine sediment records of such glacier‐fed lakes represent valuable palaeoenvironmental archives that help constrain past climate variability. In this paper, we discuss the multi‐disciplinary methodological toolbox that is applied to fingerprint a glacier signal from such lake sediments. Special emphasis is placed on dating methods, which transform stratigraphical data into climate time series, allowing us to distinguish leads and lags between archives. We also elaborate on techniques that are used to validate sediment‐based glacier signals and resolve their climate signature. Finally, we conclude with a brief outlook on new research avenues such as proxy data–climate model comparisons.  相似文献   
92.
93.
Preliminary investigations were carried out on selected samples of different ages from various alum shale localities in order to document palynofacies and content of palynomorphs as well as content and distribution of various minerals and chemical elements. There preliminary results indicate that the shales not only contain a variety of microfossils not previously recorded, but also that these fossils indicate a fresh water or saline influence. The tentative conclusion is that the uranium-bearing alum shales may have been deposited under shallow, brackish conditions with an anoxic bottom environment.  相似文献   
94.
The automatic interpretation of 3D point clouds for building reconstruction is a challenging task. The interpretation process requires highly structured models representing semantics. Formal grammars can describe structures as well as the parameters of buildings and their parts. We propose a novel approach for the automatic learning of weighted attributed context‐free grammar rules for 3D building reconstruction, supporting the laborious manual design of rules. We separate structure from parameter learning. Specific Support Vector Machines (SVMs) are used to generate a weighted context‐free grammar and predict structured outputs such as parse trees. The grammar is extended by parameters and constraints, which are learned based on a statistical relational learning method using Markov Logic Networks (MLNs). MLNs enforce the topological and geometric constraints. MLNs address uncertainty explicitly and provide probabilistic inference. They are able to deal with partial observations caused by occlusions. Uncertain projective geometry is used to deal with the uncertainty of the observations. Learning is based on a large building database covering different building styles and façade structures. In particular, a treebank that has been derived from the database is employed for structure learning.  相似文献   
95.
The stratigraphy of lake Endletvatn on northern Andøya, northern Norway, has been revisited to improve the understanding of the palaeoenvironment in the region during the Last Glacial Maximum (LGM). Four high‐quality cores were analysed with respect to various lithological parameters and macrofossil content, supplemented by 47 AMS radiocarbon dates. The sediments indicate a low‐energy environment with a mean sedimentation rate of 0.5 mm a?1. We infer perennially frozen ground in the surroundings during the LGM. Climate proxies indicate a high arctic climate (i.e. July mean temperatures between 0 and 3°C) throughout most of the LGM. The warmest periods are marked by a rise in seed, moss and animal fossils, and often also by higher organic production in the lake. These periods took place from 21.4 to 20.1, from 18.8 to 18.1, around 17 and from 16.4 cal. ka BP onwards. The shifts between the different climatic regimes occurred rapidly – probably during one or two decades. The present data do not support recently published conclusions stating that Picea, Pinus and Betula pubescens grew on Andøya during parts of the LGM. The highest relative sea level after the final deglaciation on northern Andøya is bracketed between 36 and 38 m a.s.l. It occurred between 21.0 and 20.3 cal. ka BP, peaking around 20.7 cal. ka BP. The final deglaciation of the northern tip of Andøya occurred 22.2 cal. ka BP. Then the western margin of the Andfjorden ice stream receded to the Kjølhaugen Moraine and shortly thereafter to the Endleten Moraine. Our research confirms that northern Andøya is a key location for understanding the natural environment in northwestern Europe during the LGM.  相似文献   
96.
The notion of consumer and user experience has become dominant in our society in recent years, especially in relation to leisure activities. In this study we used the experience sampling method (ESM) data collection technique in Aalborg Zoo, Denmark, to understand the distribution of subjective experiences within this site. Visitors to the zoo were asked to send phone messages (SMS) about their subjective feelings in real time and to carry with them Global Positioning System (GPS) devices that recorded their movement. This method allowed us to geotag experiences of visitors throughout the zoo compound. The results indicate that the quality of experience of visitors varies both in time and in space. We conclude that there is a need to further explore the effect of place on experiences using repeat, high-resolution measurements. In this regard we believe that geographers, who have a long tradition of studying human–environment relations, have the tools to lead this type of exploration.  相似文献   
97.
98.
Comprehensive dietary information for the endangered Australian sea lion (Neophoca cinerea) is currently limited by the deficiency and poor quality of identifiable prey remains recovered from regurgitate and faeces and the difficulty of observing feeding in the wild. In this study, we investigated DNA‐based prey detection methods using conventional (end‐point) and quantitative real‐time PCR (qPCR) on faeces collected from two captive Australian sea lions fed experimental diets of whole teleost fish, squid and shark tissue. PCR prey detection methods using the mitochondrial cytochrome oxidase subunit I (COI) and 16S genes combined with clone sequencing were compared with prey identified using traditional hard part analysis. The molecular results indicated that prey DNA was degraded. However, prey amplification was successful by targeting short (71 bp) DNA fragments. Both conventional PCR and qPCR techniques significantly increased prey detection compared with analysis of hard parts. For both sea lions, the hard part analysis was constrained by sporadic and extremely low recovery of fish otoliths (<2%), and cephalopod beaks were not recovered from the 116 squid fed. Comparisons between PCR techniques indicated comparable prey detection frequencies for all species tested; however, the sensitivity and greater resolution of qPCR improved prey detection by ~25% in one sea lion fed the experimental squid and perch. The detection of squid DNA ≤ 6 day post‐ingestion by qPCR further exhibits the ability and potential of this method to detect low concentrations of infrequent or pulse prey. This study highlights the use of DNA‐based analysis to detect prey taxa in the absence of identifiable hard prey remains.  相似文献   
99.
Glauconie inside shells of foraminifers, assumed to be formed during the timespan from the Last Glaciation to the present, is reported. The process is thought to take place at water temperatures of 6–7°C. The nature of the infilling process is suggested to be neoformation of clay minerals rather than transformation of pre-infilled clay.  相似文献   
100.
Inadequate knowledge exists on the distribution of soil moisture and shallow groundwater in intensively cultivated inland valley wetlands in tropical environments, which are required for determining the hydrological regime. This study investigated the spatial and temporal variability of soil moisture along 4 hydrological positions segmented as riparian zone, valley bottom, fringe, and valley slope in an agriculturally used inland valley wetland in Central Uganda. The determined hydrological regimes of the defined hydrological positions are based on soil moisture deficit calculated from the depth to the groundwater table. For that, the accuracy and reliability of satellite‐derived surface models, SRTM‐30m and TanDEM‐X‐12m, for mapping microscale topography and hydrological regimes are evaluated against a 5‐m digital elevation model (DEM) derived from field measurements. Soil moisture and depth to groundwater table were measured using frequency domain reflectometry sensors and piezometers installed along the hydrological positions, respectively. Results showed that spatial and temporal variability in soil moisture increased significantly (p < .05) towards the riparian zone; however, no significant difference was observed between the valley bottom and riparian zone. The distribution of soil hydrological regimes, saturated, near‐saturated, and nonsaturated regimes does not correlate with the hydrological positions. This is due to high spatial and temporal variability in depth to groundwater and soil moisture content across the valley. Precipitation strongly controlled the temporal variability, whereas microscale topography, soil properties, distance from the stream, anthropogenic factors, and land use controlled the spatial variability in the inland valley. TanDEM‐X DEM reasonably mapped the microscale topography and thus soil hydrological regimes relative to the Shuttle Radar Topography Mission DEM. The findings of the study contribute to improved understanding of the distribution of hydrological regimes in an inland valley wetland, which is required for a better agricultural water management planning.  相似文献   
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