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71.
A massive oil spill affected approximately 215 km of coastline as a result of the grounding and subsequent explosion of the supertanker Urquiola at the entrance to the harbour at La Coruña, Spain, on 12 May 1976. A total of 99–100 000 tons of Persian Gulf crude oil was lost, most of which burned, but an estimated 25–30 000 tons washed ashore. Over 2000 tons of dispersants were applied to the oil at sea. Land-based clean-up and control methods were largely inadequate to combat the spread of oil, and were ineffective at preventing large scale environmental damage.  相似文献   
72.
73.
Ohne Zusammenfassung  相似文献   
74.
Recent iron sediments forming at present in a bay of the volcanic island Palaea Kameni within the caldera of Santorini, Aegean Sea, have been investigated for their mineralogy and geochemistry. For the first time siderite has been found in a marine environment to be major constituent of a recent sediment. Further main constituents are opal, ferric hydroxide, vivianite, ferrous hydroxide, and possibly ferrous silicate. The chemical composition both of the solid material of the sediment cores and of their pore solution indicate that the ore forming solutions have originated from the leaching of volcanic kalk-alcaline rocks by hot acid solutions. This is in agreement with experimental leaching of these rock types. No enrichment of lead, copper, zinc etc. was found in the sediments. Iron oxidizing bacteria in the reddish-brown ferric hydroxide sediments now forming in bays of the Kameni Islands have been studied by light and electron microscopic investigations. Samples from the uppermost parts of the sediment consist mainly of the ferric hydroxide stalks of the iron bacteriumGallionella ferruginea. The stalks showing their morphological characteristics occur in such masses that there is no doubt concerning the presence, activity and share of these bacteria in the process of iron sedimentation. Phases of sedimentation process and kinetics of ferric hydroxide stalk formation have been determined qualitatively and quantitatively by in-situ-experiments using artificial growing surfaces (underwater “Aufwuchs” on glass slides). The results obtained are compared to similar iron sedimentation in fresh water habitats and iron rich carbonate springs discussed in literature in connection with the problem of submarine exhalative sedimentary iron ore formation.  相似文献   
75.
Zusammenfassung Die vorliegende Arbeit behandelt Gefrierkernmessungen, die im Rahmen eines europäischen Gemeinschaftsprogrammes auf dem Kleinen Feldberg/Taunus vorgenommen wurden. Ein Ziel dieser Arbeiten war die Aufdeckung und Deutung sommerlicher Anomalien der Gefrierkernkonzentration. Die Ergebnisse zeigen, daß während des Sommers 1964 aufgetretene Anomalien im wesentlichen regionalen Einflüssen zugeschrieben werden können. Ein Zusammenhang mit den an verschiedenen in Frankreich, Italien, Österreich und Spanien unterhaltenen Meßstellen gleichzeitig gewonnenen Ergebnissen ist nicht nachweisbar.
Summary This paper deals with measurements of the concentration of atmospheric freezingnuclei carried out in the frame of an European cooperative program. The investigations described here were made on Mt. Kleiner Feldberg/Taunus. They aimed at detecting and explaining anomalies of the freezing-nucleus concentration generally occurring during the summer-months. The results show that the anomalies observed on Mr. Kleiner Feldberg during summer 1964 are mainly caused by regional phenomena. There exists hardly any connection to results gained at the same time at sites of measurement in France, Italy, Austria and Spain.
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76.
We derive an analytical model of soil-gas contamination sparged into an imlined unsaturated zone. A nonaqueous phase liquid (NAPL) source lies in the capillary fringe, with an exponential sparge constant within the radius of influence and a constant ambient evaporation rate beyond. Advection, diffusion, and dispersion govern the conservative soil-gas response, expressed as a quasi-steady series solution with radial Bessel and hyperbolic vertical dependence. Simulations suggest that sparged contamination initially spreads beyond the radius of influence down a negative gradient. This gradient eventually reverses, leading to a subsequent influx of ambient contamination. Soil-gas concentrations accordingly reflect slowly varying source conditions as well as slowly varying diffusive transport through the radius of influence. The two time scales are independent: One depends on NAPL, airflow, and capillary fringe characteristics, the other on soil moisture, gaseous diffusivity, and unsaturated zone thickness. The influx of ambient contamination generates an asymptotic soil-gas concentration much less than the initial source concentration. The simple model is applied to a pilot-scale sparging study at Plattsburgh Air Force Base in upstate New York, with physically plausible results.  相似文献   
77.
Atmospheric boundary layer observations are conducted at a coastal site during a transition phase from winter to summer season over the Indian peninsula. Thermal Internal Boundary Layer (TIBL) characteristics in presence of an off-shore and a weakly influenced on-shore synoptic wind are examined with the help of measurements carried out with a mini-SODAR (SOund Detection And Ranging), tethered balloon, and tower-based micrometeorological measurements. Influence of the changing synoptic scale conditions on turbulent characteristics of TIBL is discussed. Mini-SODAR data showed the development and decay of sea and land breeze. It is seen that the characteristics of TIBL over the coastal land after sea breeze onset are similar to that of a shallow convective boundary layer (CBL) commonly found over plain land. Inside the TIBL, a maximum wind speed was noted close to the surface due to the penetration of sea breeze. In the off-shore case, a distinct sea breeze circulation was observed unlike in the case of on-shore flow. In the presence of weak on-shore case, a ‘minor sea’ breeze is noted before the establishment of sea breeze and a reduction in the momentum fluxes gives rise to decrease in the turbulence intensity. Updraft in the sea breeze front was stronger during weak synoptic conditions. Influence of synoptic changes on the sea breeze-land breeze circulation such as onset, strength and duration of the sea-land breeze are also examined. This work was done while the first author was a visiting scientist at IGCAR, Kalpakkam, India.  相似文献   
78.
The Chibougamau area, Québec, is characteristic of the internal zone of the Archean Abitibi Orogenic Belt. The paleogeographic, paleotectonic and magmatic history of the Archean sequence in the Chibougamau area is subdivided into three stages.In the first stage a submarine volcanic chain formed mainly by the effusion of submarine lava flows composed of primitive, potash-poor, tholeiitic basalt. The volcanic chain gradually grew to sea level. In the second stage, volcanic islands emerged and grew. Mainly pyroclastic eruptions of strongly differentiated, calc-alkaline andesite and dacite concentrated on the volcanic islands, whereas effusion of basalt continued at first in the surrounding basin. A felsic volcaniclastic apron was deposited around the volcanic islands. In the third stage, the volcanic islands were uplifted and were eroded to the level of their subvolcanic plutons. The debris derived from this volcanic-plutonic terrain was deposited in downfaulted marine and continental basins. The contemporaneous volcanism was shoshonitic.The first paleogeographic stage is interpreted as the growth of an immature island arc. During the second stage, the island arc became mature and its crust was thickened by accretion of plutonic material. The third stage is a period of back-arc extension.
Zusammenfassung Das Gebiet von Chibougamau, Québec, ist characteristisch für die interne Zone des Archaischen Abitibi Orogens. Man kann seine paleogeographische, paleotectonische und magmatische Geschichte in drei Phasen gliedern.Eine submarine Vulkankette formte sich in der ersten Phase, hauptsächlich durch Effusion von submarinen Lavaergüssen aus primitivem, kaliarmen, tholeiitischem Basalt. Die Vulkankette wuchs langsam bis zum Meeresspiegel. Vulkanische Inseln bildeten sich und wuchsen während der zweiten paleogeographischen Phase. Vorwiegend pyroklastische Eruptionen von stark differenzierten, kalk-alkalischem Andesit und Dazit konzentrierten sich mehr und mehr auf den Inselvulkanen, während die Effusion von Basalt zunächst in den Becken noch stattfand. Ein Mantel aus felsitischen vulkanoklastischen Gesteinen wurde um die Inselvulkane abgelagert. Die dritte Phase begann mit einer Hebung der Inselvulkane und mit ihrer Erosion bis zum Niveau ihrer subvulkanischen Plutone. Der Detritus dieses vulkanisch-plutonischen Geländes wurde in marinen und kontinentalen Verwerfungsbecken abgelagert. Der gleichalte Vulkanismus ist shoshonitisch.Wir deuten die erste paleogeographische Phase als Wachstumsphase eines primitven Inselbogens. Während der zweiten Phase reifte der Inselbogen und seine Kruste verdickte sich durch Akkretion plutonischen Materials. Die dritte Phase ist eine Periode der Dehnung im Hinterland eines Inselbogens.

Résumé La région de Chibougamau, Québec, est caractéristique de la zone interne de la ceinture orogénique archéenne de l'Abitibi. Son évolution paléogéographique, paléotectonique et magmatique se subdivise en trois phases.Lors de la première phase paléogéographique, une chaîne sous-marine de volcans se formait, essentiellement par l'émission de coulées de lave composée de basalte primitif, hypopotassique, tholéiitique. Graduellement cette chaîne volcanique s'élevait jusqu'au niveau de la mer. A la phase suivante, des îles volcaniques émergeaient et croissaient. Des éruptions essentiellement pyroclastiques d'andésites et de dacites calco-alcalines et fortement différenciées se concentraient sur les îles tandis que l'effusion de laves basaltiques continuaient dans le bassin. Un manteau de roches volcaniclastiques felsiques se déposait autour des îles volcaniques. Lors de la troisième phase, les îles volcaniques furent soulevées et furent érodées jusqu'au niveau des masses plutoniques sub-volcaniques. Le débris de ce terrain volcano-plutonique fut déposé dans des bassins de faille marins et continentaux. Des shoshonites dominaient le volcanisme contemporain.Nous interprétons la première phase paléogéographique comme une phase de croissance d'un arc insulaire immature. Lors de la deuxième phase, 1'arc insulaire devenait mature et sa croûte s'epaissît par accrétion de matériel plutoni-que. Enfin, la troisième phase est une période d'extension en arrière d'un arc insulaire.

Chibougamau, Quebec, Abitibi. , . , . . , , . . , . - , , . . . . , , . , — . — . .
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79.
Egg survival and development rate of perch eggs were investigated in Lake Zürich, Switzerland. A transplant experiment was carried out to examine whether individual females choose different depths for spawning because of an expected advantage for the development of their eggs. Egg masses which had been deposited on fir branches stuck into the ground of the lake were either left untouched or transplanted horizontally or vertically at depths of 3 and 6 m. Spawning occurred between 28 April and 9 June 1987. Egg survival to the eye pigment stage (EPS) was high in all treatments ( , minimum 92%). There was no significant difference in egg survival between treatments, suggesting that females do not choose the spawning site because of individual fitness differences related to the depth of spawning. Early egg masses which were exposed to lower temperatures developed more slowly (120–140 day degrees to the EPS) than late egg masses which were exposed to higher temperatures (80–100 day degrees). The observed differences are in agreement with the hypothesis of a constant sum of day degrees necessary for egg development using the corrected formula derived by Guma'a (1978) which deducts an estimated threshold temperature of 5°C below which development of perch eggs effectively stops, from the actual temperature.  相似文献   
80.
The ability of a high resolution (T106) version of the ECHAM3 general circulation model to simulate regional scale surface radiative fluxes has been assessed using observations from a new compilation of worldwide instrumentally-measured surface fluxes (Global Energy Balance Archive, GEBA). The focus is on the European region where the highest density of observations is found, and their use for the validation of global and regional climate models is demonstrated. The available data allow a separate assessment of the simulated fluxes of surface shortwave, longwave, and net radiation for this region. In summer, the incoming shortwave radiation calculated by the ECHAM3/T106 model is overestimated by 45 W m–2 over most of Europe, which implies a largely unrealistic forcing on the model surface scheme and excessive surface temperatures. In winter, too little incoming shortwave radiation reaches the model surface. Similar tendencies are found over large areas of the mid-latitudes. These biases are consistent with deficiencies in the simulation of cloud amount, relative humidity and clear sky radiative transfer. The incoming longwave radiation is underestimated at the European GEBA stations predominantly in summer. This largely compensates for the excessive shortwave flux, leading to annual mean net radiation values over Europe close to observations due to error cancellation, a feature already noted in the simulated global mean values in an earlier study. Furthermore, the annual cycle of the simulated surface net radiation is strongly affected by the deficiencies in the simulated incoming shortwave radiation. The high horizontal resolution of the GCM allows an assessment of orographically induced flux gradients based on observations from the European Alps. Although the model-calculated and observed flux fields substantially differ in their absolute values, several aspects of their gradients are realistically captured. The deficiencies identified in the model fields are generally consistent at most stations, indicating a high degree of representativeness of the measurements for their larger scale setting.  相似文献   
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