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1.
Abyssal currents along the northern periphery of the Shikoku Basin south of Japan were measured by current meters moored off Cape Daio-zaki, Cape Shiono-misaki and Cape Ashizuri-misaki and on the eastern foot of the northernmost part of the Kyushu-Palau Ridge. Total length of observation off Cape Shiono-misaki was about five years including the periods of the Kuroshio large meander and no meander. Analyses of current data show:
- Mean currents with a magnitude of 5–10 cm sec?1 were observed during the whole observation period at all of current meters which were set 400 m above the sea bottom that was deeper than 4,500 m. The mean current for each current meter was parallel to the local bottom contour arond each station and was toward a direction looking the Nankai Trough (a trough located along the northern end of the Shikoku Basin) to the left.
- At each station located above the shelf toe off Cape Daio-zaki and off Cape Shiono-misaki and on the foot of the Kyushu-Palau Ridge, the mean current increases with depth (a bottomward intensification of the mean current), and the vertical extent of the mean current is estimated to be about 2,000 m above the sea bottom.
- At a station located at 2,600 m depth on the continental slope off Cape Shiono-misaki, no bottom-ward intensification of currents was observed.
2.
The paper comprises analysis of telluric electric-potential differences measured across channels west and south of Oshima in the Kuroshio area to the south of Tokyo Bay during one to two years around 1960. The records are shown to involve ionospheric and magnetospheric induction noises, which are at the same or higher energy level compared to signals induced by Oceanic-dynamic processes in a frequency range of the daily and higher cycles. Channel transports estimated from potential records through eliminating the noises are verified, in reference to hydrographic observations as well as cross-channel difference in sea-level observations, to represent well the actual transport not only in the baroclinic geostrophic mode but also in the barotropic geostrophic mode and the mode deviated from geostrophy. The channel transports, which are obtained continuously in time, are proved to reveal especially well the detailed time-varying processes, on illustrating the case of an inverse-current burst happened in the Oshima-West Channel. At the end, results from spectral analyses of potential records in relation to reference quantities are presented. 相似文献
3.
Photographic observations were carried out at depths of the shelf edge at the mouth of Uchiura Inlet, Suruga Bay, central Japan in order to clarify the life style of the isocrinid stalked crinoid,Metacrinus rotundus (Echinodermata). The distribution of the species was found to be restricted to a narrow area where boulders and rock outcrops were locally present. Mean density of the crinoid was 0.05 m–2, and this value was an order of magnitude smaller than that of the deeper isocrinid,Diplocrinus wyvillethomsoni, reported from the Bay of Biscay.Metacrinus rotundus formed a parabolic filtration fan with its arms recurved into the bottom current, and was thought to be a passive suspension feeder elevating the fan into the water column by its stalk. The distal half of the stalk lay along the hard substratum and about ten groups of cirri grasped the substratum. This mode of attachment was similar to that ofCenocrinus rather than that ofDiplocrinus. Metacrinus rotundus collect food at the layer between 10 and 50 cm above the sea floor, and do not utilize a higher layer even when this layer could be utilized by climbing over a larger boulder. Resuspended benthic materials are thought to be important as a food source forM. rotundus, and the crinoids seek not only locations of stronger currents but also the position where much resuspended matter is available. 相似文献
4.
High quality CTD data were collected in the north of the Shikoku Basin where an abyssal boundary current has been observed through direct current measurements. Analyses of hydrographic data showed:
- Colder and saltier water (heavier water) compared to surrounding waters is found above the continental shelf-toe and the eastern flank of the Kyushu-Palau Ridge where the existence of the abyssal boundary current has been expected. The heavier water has a horizontal extent of about 50 km.
- The heavier water has the vertical scale of 2000 m from the sea bottom, and is associated with a thermal wind shear which enhances a component of the flow toward a direction looking the Nankai Trough (a trough located along the northern end of the Shikoku Basin) to the left in the abyss. The assumed “level of no motion” at about 2500 m depth gives the geostrophically estimated current in a good agreement with the directly measured current.
5.
硫酸皮肤素寡糖的分离与制备 总被引:2,自引:0,他引:2
利用软骨素酶 ABC (Chondroitinase ABC,EC4 .2 .2 .4 )对硫酸皮肤素 (Dermatan Sul-fate,DS)进行控制降解。对得到的混合寡糖首先采用低压凝胶渗透色谱 (L PGPC)进行分级 ,然后对每一组分再利用强阴离子交换高压液相色谱 (SAX- HPL C)进行分离 ,最终制备出聚合度为 2 ,4 ,6 ,8,10 ,12的寡糖纯品。寡糖纯度采用 SAX- HPL C,毛细管电泳 (CE)以及聚丙烯酰胺凝胶电泳(PAGE)进行检验 ,结构采用电喷雾离子化质谱 (ESI- MS)以及核磁共振波谱 (NMR)技术确定 相似文献
6.
Toshihiko Teramoto 《Journal of Oceanography》1996,52(5):633-653
Configurational structure of ocean circulation in the westernmost part of the North Pacific and its time-vayring processes are revealted through the combination of various means of measurements, that is, the measurements of cross-channel voltage, velocity profile, deep-water velocity, water characteristics together with hydrographic observations. The layered structure of circulation and current bursts of 10 to 20 days are clearly shown as well as the departure of the Kuroshio velocity-field from geostrophy. As a major process which modify the density structure of circulation, an intensified generation of internal tides over the Izu Ridge is also treated.Special lecture presented by the recipient of the prize of the Ocenographic Society of Japan for 7 April 1995. 相似文献
7.
Toshihiko Teramoto 《Journal of Oceanography》1971,27(1):7-19
A formula to determine an effective electric conductivity of channel-bed from measurements of water velocity, cross-channel potential difference and electric current-density is presented. The effective conductivity defined in this paper is the conductivity averaged over depth from channel-bed surface to a depth of the order comparable to a breadth of the channel. Effective conductivities for the Izu Island region and the Straits of Tsugaru are estimated as 2.2×10–2 mhos/m and 6.0×10–2 mhos/m, which are considerably large and very large, respectively, in comparison to most of those determined for several regions near England. High conductivities for these regions are consistent with the distribution of underground conductivity anomaly deduced from that of geomagnetic field anomaly observed at the earth's surface in Japan. An influence of underground conductivity upon measurements of sea surface water velocity with towed electrodes is estimated for the regions. 相似文献
8.
Density,biomass and community structure of demersal fishes off the Pacific coast of northeastern Japan 总被引:8,自引:0,他引:8
Demersal fish communities were studied on the lower continental shelf and the upper continental slope along the Pacific coast of northeastern Japan. Species composition, number and weight of each species were examined based on otter trawl samples at 45 stations. Mean density and biomass of demersal fishes were 131 ha–1 and 21 kg ha–1, respectively. The ten most abundant species comprised of about 95% of total number and weight of overall catch indicating simple species composition. Gadiform fishesTheragra chalcogramma, Gadus macrocephalus andPhysiculus maximowiczi were the most important species by number, weight and frequency of occurrences, and three main community types represented by the three key species were recognized.Theragra-dominant community showed higher density and biomass, and lower diversity thanPhysiculus-dominant community did. Species diversity of demersal fish community was negatively correlated to density and biomass. Density and biomass of demersal fish community were high on the uppermost slope, and the high abundance resulted from low-diversity communities dominated byT. chalcogramma andG. macrocephalus. 相似文献
9.
Summary Beppu is a water-dominated active geothermal system in Kyushu (Japan). Gold mineralization exists in places within altered Pleistocene volcanites in the southernmost part of this field. A shallow 300 m well was drilled in an alluvial fan deposit made up of unsorted volcanic clasts of andesite and dacite. Water and core samples were collected and a temperature log was carried out. In the depth range of 150-230 m and at temperatures of 126-148° C the main authigenic minerals are quartz, calcite, K-feldspar, mixed layers illite/smectite, stilbite and pyrite. The chemical data of the waters indicate that mixing occurs between shallow bicarbonate waters and deep Na-Cl geothermal waters in the outflow zone. The authigenic mineral assemblages found in the well are analogous to those found in the epithermal gold deposits of southern Kyushu. Au concentration data for the hydrothermal springs of Beppu (0.53 g/kg) indicate that the fluids found in the borehole at 148° C could theoretically deposit gold. It is reasonable to hypothesise that a process of mixing between deep Na-Cl fluids and shallow Ca-HCO3-SO4 fluids were responsible for massive silicate deposition, accompanied in places by Au mineralizations.
Contribution No 4. Foreign Visiting Scientist Section, Beppu Geophysical Research Laboratory, Kyoto University.
This paper was presented at the IGCP 291 Project Symposium Metamorphic Fluids and Mineral Deposits, ETH Zurich, March 21–23, 1991. 相似文献
Wasser-Gesteins-Wechselwirkung in einer Zone lateraler Fließbewegung: ein natürliches Beispiel aus der aktiven Geothermal-Golderz-Zone von Beppu (Kyushu, Japan)
Zusammenfassung Beppu ist ein geothermales System auf der Insel Kyushu, Japan, in der Wasser die dominante Rolle spielt. Goldvererzungen treten stellenweise in umgewandelten pleistozänen Vulkaniten im südlichsten Teil des Gebietes auf. Ein 300 m tiefes Bohrloch wurde in einem alluvialen Sedimentations-Fächer, der aus unsortierten vulkanischen Klasten, aus Andesit und Dazit besteht, niedergebracht. Wasserproben und Kernproben wurden genommen und die Temperaturen im Bohrloch systematisch gemessen. In Tiefen von 150–230 m und bei Temperaturen von 126–148°C sind die wichtigsten autigen gebildeten Minerale Quarz, Calcit, K-Feldspat, Illit/Smectit, Stilbit und Pyrit. Der Chemismus der Wässer zeigt, daß eine Mischung zwischen seichten Bikarbonat-Wässern und aus der Tiefe stammenden Na-Cl geothermalen Wässern erfolgt. Die autigenen Mineralassoziationen in diesem. Bohrloch sind vergleichbar mit denen in epithermalen Goldlagerstätten des südlichen Kyushu. Auf der Basis von existierenden Goldkonzentrationsdaten für die hydrothermalen Quellen auf Beppu (0.53 g/kg) läßt sich zeigen, daß die Fluide, die in dem Bohrloch bei 148 angetroffen wurden, theoretisch Gold absetzen könnten. Daher läßt sich die Theorie vertreten, daß Mischungsvorgänge zwischen einem aus der Tiefe stammenden Na-Cl Fluid und einem oberflächennahen Ca-HCO3-SO4 Wasser für die massive Silikatausscheidung verantwortlich waren, die stellenweise von Goldmineralisation begleitet wurden.
Contribution No 4. Foreign Visiting Scientist Section, Beppu Geophysical Research Laboratory, Kyoto University.
This paper was presented at the IGCP 291 Project Symposium Metamorphic Fluids and Mineral Deposits, ETH Zurich, March 21–23, 1991. 相似文献