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81.
Abstract. Nitzschia sicula (C astr .) H ust ., a planktonic pennate diatom, dominated the microphytoplankton (104 -5 times 104 cells. 1-1 ) in the central, oligotrophic Southern Adriatic Pit waters (20-50m layer) in May 1990. Nauplii dominated the microzooplankton (3 indiv. 1-1 in the 0-50m layer, 130 μm mean body length) and produced a considerable amount of faecal (mini)pellets (1900. 1-1 at 50m, mean diameter 47μm), which were compactly filled with N. sicula frustules. The subsurface accumulation of diatoms and nauplii was probably the result of both productive activity under specific hydrographic conditions and the convergence in a relatively strong southern Adriatic cyclonic gyre; the advective transport of populations along the shear zone, at the boundary between water masses of different thermo-haline characteristics may also have played a role. The amount of minipellets was high if compared with the data available from other seas. This was probably due to high production of minipellets, their slow sinking rate, and/or an absence of manipulation of the faecal material by zooplankton. 相似文献
82.
In February, May and August 1994, four stations in the North Sea (viz. at the Broad Fourteens, Frisian Front, German Bight and Skagerrak) were visited to sample near-bottom particulate organic matter. Samples, taken by means of a pump, a sediment trap and a sediment recorder, were analysed on organic carbon, total nitrogen, phytopigments and fatty acids. These molecular markers were used to describe the nature and quality of the organic particles in the near-bottom water. Principal component analysis showed chlorophyll a, phaeopigments and fatty acids to be useful markers for the quality of organic matter and yield complementary information.The quality of the near-bottom particles appeared to be related to the local hydrography and depositional circumstances. The Broad Fourteens station, a non-depositional sandy site along the Dutch coast, showed organic particles to be relatively fresh, little influenced by resuspended sedimentary material. Near-bottom organic particles on this site contained relatively high shares of chlorophyll a and polyunsaturated fatty acids, characteristic of algal matter. On the other hand the particulate organic material on the two depositional locations, the Frisian Front and the German Bight stations, was influenced by resuspension of sedimentary organic particles poor in pigments and fatty acids. Amounts of carbon trapped in the near-bottom environment at the Skagerrak station were lower than expected from the literature. 相似文献
83.
秦山核电站邻近水域的基本水文特征 总被引:2,自引:0,他引:2
文章根据1989年4、7、10月和1990年1月在秦山核电站邻近水域获得的水文观测资料,对该区域中海水温度、盐度、浊度、水色和透明度以及潮汐、潮流等要素的分布和变化特征进行了较为详尽的分析,为进一步了解该水域的基本水文状况和海水运动的基本规律提供了重要依据。 相似文献
84.
Carrada G.C. Hopkins T.S. Bonaduce G. Ianora A. Marino D. Modigh M. Ribera D'Alcalà M. Scotto di Carlo B. 《Marine Ecology》1980,1(2):105-120
Abstract. Recent observations of physico-chemical and biological parameters in the Gulf of Naples are summarized. The water masses present within the Gulf during the various periods of the year are described. The temporal and spatial distribution of surface nutrients (N-NO3 , P-PO4 , Si-SiO4 ) and chlorophyll a are reported and the areas exposed to local eutrophication are identified. Biweekly sampling at a reference station has permitted us also to identify both phytoplankton and zooplankton seasonal cycles. The morphology of the basin and the uneven land runoff distribution are interpreted as causal to the variability of chemico-physical parameters and of the associated biological communities, giving rise to two subsystems (coastal and "open water") within the Gulf. 相似文献
85.
1987年9月,我们进行了一次详细的调查,确定了东库克海峡(Cook Stait)中腔吻鳕的卵及稚鱼分布与水文状况的关系。由于地方性风的原因,当地的水文结构非常复杂。南塔拉纳基湾(Taranaki Bight)水占据了库克海峡北部和中部的大部分水域。克劳迪湾(Cloudy Bay)沿岸水被河水冲淡,并由于库克海峡峡谷上升流进入克利福德湾(Clifford Bay)和开普.坎贝尔(Cape Campbell)南部沿岸,使克劳迪湾的沿岸水向近岸呈羽状伸展。东开普流水体出现在库克海峡峡谷水深200m附近和陆架外缘。开普.帕利瑟(Cape Palliser)南部的深层混合说明,该地区有一股反气旋涡旋。叶绿素α浓度与混合层深度有关,它在垂直分层的表面水体中最高。腔吻鳕卵在库克海峡峡谷内最多,该地区是这种鱼类著名的产卵场。小的腔吻鳕稚鱼(2.0~3.9mm)数在卵高密度集区和开普。坎贝尔附近最多,而较大的稚鱼(>10mm)在近岸区最多。根据刚孵化出来的稚鱼的分布情况来看,腔吻鳕卵随着当地的上升流进入开普。坎贝尔的近岸地区。 相似文献
86.
THE MONSOON IN THE ARABIAN SEA:IMPLICATIONS FROM RADIOLARIAN FLUXES TO THE DEEP SEA 相似文献
87.
88.
介绍了第18届国际海道测量大会概况,通过实地见闻,简要总结和展望了国际海道测量发展的新趋势。旨在对我国海洋测绘事业的发展提供借鉴和参考。 相似文献
89.
Norbert Dankers Michel Binsbergen Koos Zegers Remi Laane Michiel Rutgers van der Loeff 《Estuarine, Coastal and Shelf Science》1984,19(2):143-165
Transport processes were studied in a gully between a salt marsh and an estuary. After storm tides, ebb currents in the gully reached high values. It is concluded that particulate matter (both organic and inorganic) are imported into the marsh. Coarse organic debris is exported during storm tides, but this amount is low when compared with the primary production on the marsh. Exports are shown for dissolved organic carbon, ammonia, phosphate and silica, while nitrate and possibly nitrite are imported. Organic matter derived from in situ production and net import is buried and partly mineralized in the marsh. 相似文献
90.
Climate induced changes in the circulation and dispersal patterns of the fluvial sources during late Quaternary in the middle Bengal Fan 总被引:2,自引:0,他引:2
From a transact along 15‡N latitude in the middle Bengal Fan, temporal and spatial variations in the granulometric parameters
and clay minerals in14C dated box cores from the eastern, the central and the western regions were studied to determine climate induced changes
in the hydrography. Clay assemblages have spatial and temporal changes and are markedly different in the eastern and the western
bay. From a high abundance of the clay smectite, which has its major source in the Deccan Basalt in peninsular India, it is
inferred that the western bay is predominantly a depocenter of ‘peninsular sources”. The eastern and the central regions of
the bay, however, mostly receive sediments of the ‘Himalayan source’. Related to unstable climate, the reported dominant illite-chlorite
(I + C) assemblage in the eastern region of the bay (I + C > 60% smectite <15%), between 18 and 12.6 ka BP, points to a predominant
supply from the Himalayan sources through equatorwards dispersal by the winter hydrography. Higher smectite, and reduced clays
of the Himalayan sources (smectite > 25%; I + C > 45%) are reported also after 12.5 ka BP from the eastern bay. These are
interpreted as evidences of an intensified SW monsoon and associated change in the dispersal pattern by stronger summer monsoon
hydrography which supports across bay dispersal by anticyclonic gyre. The influence of climate on hydrographic changes is
consistent during the short events of arid climate (weak NE monsoon) in Holocene in core 31/1 (western bay), in which the
enhanced contents of the clays of the Himalayan sources are observed (smectite < 40% I + C > 50%). These findings have implications
for climate regulated influence of fluvial processes over the areas, hitherto, considered unaffected by the Indian peninsular
fluvial sources 相似文献