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1.
Yngve Öhman 《Solar physics》1969,10(1):178-183
During a stay at the Kitt Peak National Observatory the writer has tried to find an influence of flare radiation on the high photospheric and low chromospheric lines of the area occupied by the flare. Observations have been made in the H region and in the region of the H and K lines. When flare emission is present in sunspots some of the faint (molecular) lines seem to be weakened. When a flare appears near the solar limb some of the Evershed-type (chromospheric) lines are strongly influenced.Kitt Peak National Observatory Contribution No. 481.Visiting Astronomer to the Solar Division, Kitt Peak National Observatory, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation. 相似文献
2.
Kristoffersen Brage S. Bellout Mathias C. Silva Thiago L. Berg Carl F. 《Mathematical Geosciences》2021,53(8):1881-1905
Mathematical Geosciences - A data-driven automatic well planner procedure is implemented to develop complex well trajectories by efficiently adapting to near-well reservoir properties and geometry.... 相似文献
3.
We present the first multi-channel seismic reflection data ever collected from the Eurasian Basin of the Arctic Ocean. The 200 km data set was acquired by a 20 channel sonobuoy array deployed at U.S. ice drift station FRAM-IV and operated for 34 days about 370 km north of Svalbard in April–May 1982. Cross array drift and ice floe rotation which may constitute the most serious obstacle to the advantage of multi-channel data acquisition did only occur to a minor degree during the experiment and render most of the data set suitable for processing using common mid-point binning.A 0.7–1.4 s (two-way traveltime) thick sedimentary section has been deposited over oceanic crust of mid-Oligocene age below the Barents Abyssal Plain. In the deepest part, sediments are infilling topographic lows which indicate predominantly turbidite deposition. Erosional truncations are only locally present in the central part of the section. Conformable bedforms deposited over gentle basement highs indicate a relatively stable bottom current regime since mid-Oligocene time. Thus the establishment of a deep water connection between the Arctic Ocean and lower latitude water masses appear to have had only minor effect on Eurasian Basin bottom current circulation.Extensive submarine slide scars on the north slope of Yermak Plateau show that mass waste have been a sediment source to the Barents Abyssal Plain. 相似文献
4.
The Palaeozoic intracratonic basins in northwest Gondwana, i.e. the Amazonas, Parnaiba and Acera basins, probably opened during late Caradoc and Ashgill times. The fluviatile sedimentation later changed to littoral at the basinal margins. A transgression from the north-west region of Gondwana slowly overlapped the margins of the intracratonic basins. The transgression reached its maximum in the Rawtheyan (late Ashgill), as evidenced by fossiliferous shallow marine sediments in the Amazonas Basin. The Hirnantian glaciation in north Gondwana lowered the sea level, and in the Amazonas Basin a littoral sedimentation followed on shallow marine strata. From the opening of the basins onwards, a shallow sea probably existed close to the epicontinental basins in north-west Gondwana. The basins were connected via a narrow passage between the Guayana and Ivorian cratons. 相似文献
5.
Anders Bryn Geir-Harald Strand Michael Angeloff Yngve Rekdal 《Norsk geografisk tidsskrift. Norwegian journal of geography》2018,72(3):131-145
The Norwegian area frame survey of land cover and outfield land resources (AR18X18), completed in 2014, provided unbiased statistics of land cover in Norway. The article reports the new statistics, discusses implications of the data set, and provides potential value in terms of research, management, and monitoring. A gridded sampling design for 1081 primary statistical units of 0.9 km2 at 18?km intervals was implemented in the survey. The plots were mapped in situ, aided by aerial photos, and all areas were coded following a vegetation type system. The results provide new insights into the cover and distribution of vegetation and land cover types. The statistic for mire and wetlands, which previously covered 5.8%, has since been corrected to 8.9%. The survey results can be used for environmental and agricultural management, and the data can be stratified for regional analyses. The survey data can also serve as training data for remote sensing and distribution modelling. Finally, the survey data can be used to calibrate vegetation perturbations in climate change research that focuses on atmospheric–vegetation feedback. The survey documented novel land cover statistics and revealed that the national cover of wetlands had previously been underestimated. 相似文献
6.
Per Berggren Rasha Ishaq Yngve ZebÜhr Carina Nf Cecilia Bandh Dag Broman 《Marine pollution bulletin》1999,38(12):238-1084
Patterns and levels of chlorinated aromatic contaminants (DDTs, PCBs, non-ortho PCBs and PCDD/Fs) in blubber tissue were compared among six sample groups of male harbour porpoises (Phocoena phocoena) from the Baltic Sea, the Kattegat-Skagerrak Seas and the west coast of Norway. A principal component and classification analysis showed that mature harbour porpoises from the Baltic had significantly different contaminant patterns than animals from the Kattegat-Skagerrak and Norway. ANOVAs showed that mature porpoises from the Baltic had higher levels of ΣPCB and several individual PCBs and PCDD/Fs than the Kattegat-Skagerrak and the Norwegian samples and higher ΣDDT than the Norwegian. A comparison between immature porpoises showed that Baltic animals had higher levels of ΣPCDD/F than the corresponding sample from the Kattegat-Skagerrak. The levels of ΣDDT, ΣPCB and Σnon-ortho PCB were significantly higher in animals collected during 1978–81 compared to animals collected in 1988–90 indicating a temporal decline of these organochlorines in the Kattegat-Skagerrak Seas. The contaminant levels recorded in the Baltic Sea are a serious cause for concern and could have management implications for the already threatened harbour porpoises in this area. 相似文献
7.
Yngve Öhman 《Solar physics》1972,23(1):134-141
From material secured with the McMath Solar Telescope of the Kitt Peak National Observatory rotational (orbital) motion has been found in a prominence ejected from a rotating flare. A period of rotation of 32 min has been derived from the study of a periodic asymmetry of the AL i 3961 absorption line.Presented at the Physics of Prominences-colloquium at Anacapri, September 29, 1971. 相似文献
8.
9.
Yngve Grahn Paula Mendlowicz Mauller Egberto Pereira Stanislas Loboziak 《Journal of South American Earth Sciences》2010,29(2):354-370
The Alto Garças Sub-basin in the northern part of the Paraná Basin evolved differently from the Apucarana Sub-basin in the south. The marine environment was shallower in the Alto Garças Sub-basin, which contains proportionately more silty and arenaceous rocks. The formations and members defined in the Apucarana Sub-basin are therefore difficult to apply in the Alto Garças Sub-basin, where the Chapada Group (units 1–4) is more applicable. An integrated miospore and chitinozoan biozonation of the Chapada Group facilitates direct correlation between the Chapada Group’s units and the classical formations of the Paraná Basin as defined in the Apucarana Sub-basin. The Furnas Formation and Chapada unit 1 constitute the same lithostratigraphic unit. Beds with rhyniophytes in the uppermost part of the Furnas Formation contain palynomorphs representative of the Si phylozone within the MN spore Zone (late Lochkovian), and the rhyniophyte beds occupy the same stratigraphic interval within Chapada unit 1 (the Lochkovian of the Paraná Basin lacks chitinozoans). The lower part of Chapada unit 2 contains spores of the PoW Su spore Zone and chitinozoans of the Ramochitina magnifica and Ancyrochitina pachycerata zones, together indicating a late Pragian–early Emsian age-span. The upper part of Chapada unit 2 corresponds to the GS (AP) and Per (AD pre-Lem) spore Zones, and chitinozoans of the Ancyrochitina parisi, the informal Ancyrochitina varispinosa and Alpenachitina eisenacki chitinozoan zones, thus suggestive of a late Emsian – earliest Givetian age-span. Unit 3 is a proximal and lateral facies equivalent of the upper part of unit 2. The lower part of unit 4 includes spores typical of the early Givetian Lli (AD Lem) spore Zone and chitinozoans of the Ramochitina stiphrospinata chitinozoan Zone; the uppermost (early late Frasnian) part contains spores of the lower BMu (IV) spore Zone and chitinozoans of the Lagenochitina avelinoi chitinozoan Zone. The sandstones of unit 3 were inundated during the earliest Givetian, and the resultant flooding surface marks the base of unit 4 basin-wide. Clearly, the two sub-basins were distinct depositional centers during the Devonian. 相似文献
10.
Fluid inclusions act as sealed vessels containing information about the fluid environment in which the minerals precipitated, and until decrepitated, the chemical composition of the fluid inside the inclusion stays intact. In many cases fluid inclusions contain trapped hydrocarbons, which may provide useful information in paleontological, organic geochemical and astrobiological research since they act as containers of non-contaminated organic matter with a defined minimum age. Here we present a novel concept for extraction of fluid inclusions in preparation for application to extract single fluid inclusions. The method is based on the illumination of a sample with an ErYAG laser (). The wavelength of the laser is absorbed by water and organic material, and with the minerals encapsulating the inclusions transparent to the wavelength, the fluid will expand and the inclusion will decrepitate. The initial results of our study demonstrate that fluid inclusions can be extracted by the use of an ErYAG laser, and that organic biomarkers may survive the process, readily available for GC–MS analysis. 相似文献