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排序方式: 共有333条查询结果,搜索用时 15 毫秒
81.
Joan A. Vorpahl 《Solar physics》1973,28(1):115-122
I examined a moderately active sunspot group, McMath 9735, and found that 15 of 16 flares observed in 1968, October 20–21 occurred near, and were preceded by, at least one of several EFR's (Emerging Flux Regions) in the area. Flares were larger and more numerous when: (1) the EFR appeared close to already existing spots, (2) a large amount of filament reorientation was occurring, and when (3) the EFR was most active, i.e., it was increasing in area and brightness and was accompanied by violent surging and great brightness fluctuations at the feet of the dark fibrils. Only two flares occurred at an inverted EFR, i.e., a leading spot with f polarity, however the largest event (2B) of the 15 quickly spread to this region after starting in a different EFR. A sunspot appeared in the inverted emerging flux region less than three hours after the flares. However this is thought to be merely an indication of the growing EFR and, therefore, a secondary effect. 相似文献
82.
M. T. Camacho Olmedo M. Paegelow J. F. Mas 《International journal of geographical information science》2013,27(12):2343-2361
This study compares two types of intermediate soft-classified maps. The first type uses land use/cover suitability maps based on a multi-criteria evaluation (MCE). The second type focuses on the transition potential between land use/cover categories based on a multi-layer perceptron (MLP). The concepts and methodological approaches are illustrated in a comparable manner using a Corine data set from the Murcia region (2300 km2, Spain) in combination with maps of drivers that were created with two stochastic, discretely operating, commonly used tools (MCE in CA_MARKOV and MLP in Land Change Modeler). The importance of the different approaches and techniques for the obtained results is illustrated by comparing the specific characteristics of both approaches by validating the suitability versus transition potential maps to each other using a Spearman correlation matrix and, between the Corine maps, using classical ROC (receiver operating characteristic) statistics. Then, we propose a new use of ROC statistics to compare these intermediate soft-classified maps with their respective hard-classified maps of the models for each category. The validation of these results can be beneficial in choosing a suitable model and provide a better understanding of the implications of the different modeling steps and the advantages and limitations of the modeling tools. 相似文献
83.
O. Groussin J. Licandro J. Helbert J. L. Reynaud P. Levacher M. Reyes García-Talavera V. Alí-Lagoa P. E. Blanc E. Brageot B. Davidsson M. Delbó M. Deleuze A. Delsanti J. J. Diaz Garcia K. Dohlen D. Ferrand S. F. Green L. Jorda E. Joven Álvarez J. Knollenberg E. Kührt P. Lamy E. Lellouch J. Le Merrer B. Marty G. Mas C. Rossin B. Rozitis J. Sunshine P. Vernazza S. Vives 《Experimental Astronomy》2016,41(1-2):95-115
We present THERMAP, a mid-infrared spectro-imager for space missions to small bodies in the inner solar system, developed in the framework of the MarcoPolo-R asteroid sample return mission. THERMAP is very well suited to characterize the surface thermal environment of a NEO and to map its surface composition. The instrument has two channels, one for imaging and one for spectroscopy: it is both a thermal camera with full 2D imaging capabilities and a slit spectrometer. THERMAP takes advantage of the recent technological developments of uncooled microbolometer arrays, sensitive in the mid-infrared spectral range. THERMAP can acquire thermal images (8–18 μm) of the surface and perform absolute temperature measurements with a precision better than 3.5 K above 200 K. THERMAP can acquire mid-infrared spectra (8–16 μm) of the surface with a spectral resolution Δλ of 0.3 μm. For surface temperatures above 350 K, spectra have a signal-to-noise ratio >60 in the spectral range 9–13 μm where most emission features occur. 相似文献
84.
85.
Ma. Edweena Joan A. Cabato Kelvin S. Rodolfo Fernando P. Siringan 《Journal of Asian Earth Sciences》2005,25(6):849
Subic Bay sediments and faults identified in seismic-reflection profiles were dated using sea-level curves. The oldest sedimentary packages are marine sediments subaerially exposed and eroded 20 ka. Fluvio-marine to wholly marine sediments were deposited during the ensuing transgression, and prograding units were deposited during stillstands or minor sea-level falls. Faults within the bay have three age ranges. The oldest set cuts through the pre-δ18O Stage 2 rock units, >18 ka; a second disrupts 10.2–11.3 ka sediments; and the youngest, which cut the uppermost sedimentary package, show that movements occurred about every 2 ky, most recently about 3 ka. Northwest–southeast faults that parallel onshore structures associated with Paleogene emplacement of the Zambales Ophiolite Complex to the west and north likely represent rejuvenated tectonism. The northern coastline and north–south-trending axial bay islands appear related to a lineament that dissects Mt Pinatubo farther northeast. A breach in the caldera of Mt Natib is the most likely source of a presumed pyroclastic deposit in the eastern bay that is associated with sediments about 11.3–18 ka, indicating that a Natib eruption occurred much more recently than previously documented for this volcano. 相似文献
86.
87.
Joan A. Vorpahl 《Solar physics》1978,57(2):297-308
We have used the S-056 X-ray data from Skylab to determine quantitative values for the coronal conditions characterizing a new bipolar magnetic region (BMR). In particular, we include: (a) the time variation of the total soft X-ray flux from the BMR as a function of time; (b) the temporal and spatial variation of the temperature and emission measure; (c) the variation with time of thermal energy density; (d) the (calculated) magnetic field configuration and magnetic flux density in the corona; and (e) the temporal variation of the magnetic field energy in the corona. Detailed comparisons are made between the configuration of X-ray features and the magnetic field topology. 相似文献
88.
Anthony Lehmann Stefano Nativi Paolo Mazzetti Joan Maso Ivette Serral Daniel Spengler 《International Journal of Digital Earth》2020,13(2):322-338
ABSTRACTWhen defining indicators on the environment, the use of existing initiatives should be a priority rather than redefining indicators each time. From an Information, Communication and Technology perspective, data interoperability and standardization are critical to improve data access and exchange as promoted by the Group on Earth Observations. GEOEssential is following an end-user driven approach by defining Essential Variables (EVs), as an intermediate value between environmental policy indicators and their appropriate data sources. From international to local scales, environmental policies and indicators are increasingly percolating down from the global to the local agendas. The scientific business processes for the generation of EVs and related indicators can be formalized in workflows specifying the necessary logical steps. To this aim, GEOEssential is developing a Virtual Laboratory the main objective of which is to instantiate conceptual workflows, which are stored in a dedicated knowledge base, generating executable workflows. To interpret and present the relevant outputs/results carried out by the different thematic workflows considered in GEOEssential (i.e. biodiversity, ecosystems, extractives, night light, and food-water-energy nexus), a Dashboard is built as a visual front-end. This is a valuable instrument to track progresses towards environmental policies. 相似文献
89.
Latent lifestyle preferences and household location decisions 总被引:1,自引:2,他引:1
Lifestyle, indicating preferences towards a particular way of living, is a key driver of the decision of where to live. We
employ latent class choice models to represent this behavior, where the latent classes are the lifestyles and the choice model
is the choice of residential location. Thus, we simultaneously estimate lifestyle groups and how lifestyle impacts location
decisions. Empirical results indicate three latent lifestyle segments: suburban dwellers, urban dwellers, and transit-riders.
The suggested lifestyle segments have intriguing policy implications. Lifecycle characteristics are used to predict lifestyle
preferences, although there remain significant aspects that cannot be explained by observable variables.
相似文献
Jieping LiEmail: |