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421.
Impact of accounting for coloured noise in radar altimetry data on a regional quasi-geoid model 总被引:1,自引:1,他引:0
We study the impact of an accurate computation and incorporation of coloured noise in radar altimeter data when computing a regional quasi-geoid model using least-squares techniques. Our test area comprises the Southern North Sea including the Netherlands, Belgium, and parts of France, Germany, and the UK. We perform the study by modelling the disturbing potential with spherical radial base functions. To that end, we use the traditional remove-compute-restore procedure with a recent GRACE/GOCE static gravity field model. Apart from radar altimeter data, we use terrestrial, airborne, and shipboard gravity data. Radar altimeter sea surface heights are corrected for the instantaneous dynamic topography and used in the form of along-track quasi-geoid height differences. Noise in these data are estimated using repeat-track and post-fit residual analysis techniques and then modelled as an auto regressive moving average process. Quasi-geoid models are computed with and without taking the modelled coloured noise into account. The difference between them is used as a measure of the impact of coloured noise in radar altimeter along-track quasi-geoid height differences on the estimated quasi-geoid model. The impact strongly depends on the availability of shipboard gravity data. If no such data are available, the impact may attain values exceeding 10 centimetres in particular areas. In case shipboard gravity data are used, the impact is reduced, though it still attains values of several centimetres. We use geometric quasi-geoid heights from GPS/levelling data at height markers as control data to analyse the quality of the quasi-geoid models. The quasi-geoid model computed using a model of the coloured noise in radar altimeter along-track quasi-geoid height differences shows in some areas a significant improvement over a model that assumes white noise in these data. However, the interpretation in other areas remains a challenge due to the limited quality of the control data. 相似文献
422.
Prof. Dr. Kurt Wegener 《Pure and Applied Geophysics》1950,18(1):155-157
Summary The method of the equilibrium of radiation is demonstrated on two observed series of observations.
Resumen El método del equilibrio de irradiación utilízase en 2 series de observaciones.相似文献
423.
Kurt Wegener 《Pure and Applied Geophysics》1961,48(1):178-180
Summary The radiation as origin of the weather.
Résumé Le temps, comme dépendant de la radiation solaire.相似文献
424.
Kurt Leuchs 《International Journal of Earth Sciences》1926,17(2):151-159
Ohne Zusammenfassung 相似文献
425.
426.
James P. Barry Kurt R. Buck Chris F. Lovera Linda Kuhnz Patrick J. Whaling Edward T. Peltzer Peter Walz Peter G. Brewer 《Journal of Oceanography》2004,60(4):759-766
Purposeful deep-sea carbon dioxide sequestration by direct injection of liquid CO2 into the deep waters of the ocean has the potential to mitigate the rapid rise in atmospheric levels of greenhouse gases.
One issue of concern for this carbon sequestration option is the impact of changes in seawater chemistry caused by CO2 injection on deep-sea ecosystems. The effects of deep-sea carbon dioxide injection on infaunal deep-sea organisms were evaluated
during a field experiment in 3600 m depth off California, in which liquid CO2 was released on the seafloor. Exposure to the dissolution plume emanating from the liquid CO2 resulted in high rates of mortality for flagellates, amoebae, and nematodes inhabiting sediments in close proximity to sites
of CO2 release. Results from this study indicate that large changes in seawater chemistry (i.e. pH reductions of ∼0.5–1.0 pH units)
near CO2 release sites will cause high mortality rates for nearby infaunal deep-sea communities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
427.
Lars Chresten Lund-Hansen Einer Larsen Kurt Thomas Jensen Kim N. Mouritsen Christian Christiansen Thorbj rn Joest Andersen Gunnild V lund 《Marine Georesources & Geotechnology》2004,22(1):115-122
A newly developed video and camera system for tidal flat microtopographic studies is presented. It consists of a SONY handy cam placed in an underwater housing mounted on a frame about 70 cm above the sediment surface. A rectangular surface area of 30 ×40 cm is imaged by the camera. The camera records video sequences and/or digital images at predetermined time lapses. The total number of images is about 540, and a similar number of 10-second long video sequences can be recorded. The camera is programmed with a PC before deployment, and the total deployment time depends on the time lapse between recordings. The camera is connected to an external power supply (12 volt), and a halogen projector pointing towards the sediment surface ensures that the system is operable on a 24-hours scale. The system has been tested in the Danish Wadden Sea. It has proved to be a very useful tool in studies of topographic effects of erosion and deposition sequences, and for studies of benthic organisms-sediment interactions. The test site was further equipped with sensors for water and seabed measurements, which proved to be indispensable regarding the interpretation of recorded image time-series. 相似文献
428.
Prof. Dr. Kurt Wegener 《Pure and Applied Geophysics》1953,26(1):191-197
Zusammenfassung Die Möglichkeiten einer mechanischen Registrierung der Verteilung der Energie im Spektrum der Sonne werden gezeigt.
Summary The possibility of a mechanical record of the distribution of energy in the spectre of the sun is demonstrated.相似文献
429.
Ohne Zusammenfassung 相似文献
430.
Salt-water discharges from a fault system in the crystalline basement of the Black Forest into the gravel aquifer of the
Kinzig River valley near Ohlsbach, upper Rhine River valley, southwestern Germany. The salt water (TDS, 16 g/kg) ascends from
a reservoir at 1 3 km depth. Once discharged into the gravel aquifer, the saline deep water mixes with fresh groundwater
and is carried along the groundwater flow path to the middle of the Rhine River valley. There, the natural geogene salt-water
plume merges with a man-made chloride-rich infiltration zone along the Rhine River. The plume was mapped using (1) chloride
data from groundwater observation wells, and (2) resistivity data from geoelectric sounding. Background chloride is about
7 mg/kg. In the central region of the plume, chloride concentration exceeds 200 mg/kg. A continuous area of Cl 1 50 mg/kg
is distinguished from the discharge fault to the Rhine River over a distance of 12 km. Resistivities range from 1 50 Ω in
uncontaminated regions to <7 Ω in the 700 m-long central region of the plume. A low resistivity plume (7–10 Ω) stretches for
1 7 km into the Rhine River valley. The two plume maps are in good agreement.
Received, April 1998 / Revised, November 1998, January 1999 / Accepted, January 1999 相似文献