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91.
92.
The Gulf of Kachchh in western India, with its arid climate, large semi-diurnal tidal amplitudes, negative water balance and near-pristine water quality, is being extensively developed as oil importing bases for economic reasons in connection with its proximity to the oil exporting countries of the Middle East. Besides, new coral rubbings were sighted in Jakhau, north-western Gulf of Kachchh. Dredging in Mandvi of the north Gulf covering 3.5 km2 revealed a similar assortment of live corals with their associated flora and fauna. These pioneering observations demonstrate that there exist live corals of young polyps-colony of Favia sp. belonging to the family Faviidae in the north-western Gulf of Kachchh. The environmental parameters there were carefully recorded as: surface water temperature (°C) varying from 29 to 31.8, salinity (ppt), pH, dissolved oxygen (mgL−1) and total suspended solids (mgL−1) in the ranges of 37–43.5, 7.7–8.45, 5.4–6.8 and 11–31, respectively.  相似文献   
93.
Anthropogenic threats to cold-water coral reefs are trawling and hydrocarbon drilling, with both activities causing increased levels of suspended particles. The efficiency of Lophelia pertusa in rejecting local sediments and drill cuttings from the coral surface was evaluated and found not to differ between sediment types. Further results showed that the coral efficiently removed deposited material even after repeated exposures, indicating an efficient cleaning mechanism. In an experiment focusing on burial, fine-fraction drill cuttings were deposited on corals over time. Drill cutting covered coral area increased with repeated depositions, with accumulation mainly occurring on and adjacent to regions of the coral skeleton lacking tissue cover. Tissue was smothered and polyp mortality occurred where polyps became wholly covered by material. Burial of coral by drill cuttings to the current threshold level used in environmental risk assessment models by the offshore industry (6.3 mm) may result in damage to L. pertusa colonies.  相似文献   
94.
本文通过对晚石炭世及早二叠世几种常见复体四射珊瑚的骨骼,尤其是隔壁的电镜研究、划分出了4种重要的隔壁微细构造类型,并指出了这些微细构造类型的地层分布规律及其在分类中的意义。  相似文献   
95.
对中国珊瑚药用状况和研究现状进行了调查.结果表明,中国有造礁石珊瑚、柳珊瑚、软珊瑚等珊瑚物种 490 种,民间药用的仅有22种.目前,已经对100种南海软珊瑚和柳珊瑚进行了化学成分的研究.其中,软珊瑚以豆荚软珊瑚Lobophytum,肉芝软珊瑚Sarcophyton,短指软珊瑚Sinularia,柔荑软珊瑚Nephthea和异花软珊瑚Xenia等属研究较多,柳珊瑚以小月柳珊瑚Menella,竹节柳珊瑚Isis和灯芯柳珊瑚Junceella等属研究较多.主要化合物结构类型包括二萜、甾体、倍半萜,含氮化合物等,其中部分化合物显示较强的抗肿瘤、抗菌、抗氧化、防生物附着等多种生物活性,具有潜在的药物开发应用价值.  相似文献   
96.
Population outbreaks of crown-of-thorns sea star (Acanthaster planci L.) remain one of the most significant biological disturbances on tropical coral reefs although the increasing attention given to other threats has greatly limited recent progress in understanding the cause and consequences of this phenomenon. In September 2005 dramatic increases in the abundance of A. planci were observed on reefs within Bootless Bay, Central Province, Papua New Guinea, where few crown-of-thorns have previously been reported. Densities of A. planci peaked at 162 sea stars per hectare and caused extensive coral mortality. This outbreak killed upwards of 55% of live corals, reducing overall coral cover from 42.4% in 2005 down to just 19.1% in March 2006. Declines in coral cover were largely driven by widespread mortality of Acropora spp. which dominated reef assemblages prior to the outbreak. The extensive depletion of Acropora spp. greatly altered the coral composition as well as the physical structure of reef habitats. In the absence of any other major disturbances these coral communities are likely to quickly recover, but this outbreak highlights the ongoing contribution of A. planci to degradation of coral reef environments.  相似文献   
97.
Abstract. Along the Sinai coast of the Red Sea a deep diving survey with the research submersible GEO investigated the depth distribution of stony corals. 47 hermatypic species were identified below 50 m; 9 species extended below 100 m. Their depth distributions are related to light penetration. Observed changes in hermatype growth forms with depth were investigated and interpreted as photo-adaptations. 10 species of ahermatypic corals were found between 100–205 m. Ahermatype growth forms are adaptations to plankton feeding and do not change with depth.  相似文献   
98.
The Darwin Mounds are a series of small (5 m high, 75–100 m diameter) sandy features located in the northern Rockall Trough. They provide a habitat for communities of Lophelia pertusa and associated fauna. Suspended particulate organic matter (sPOM) reaching the deep-sea floor, which could potentially fuel this deep-water coral (DWC) ecosystem, was collected during summer 2000. This was relatively “fresh” (i.e. dominated by labile lipids such as polyunsaturated fatty acids) and was derived largely from phytoplankton remains and faecal pellets, with contributions from bacteria and microzooplankton. Labile sPOM components were enriched in the benthic boundary layer (10 m above bottom (mab)) relative to 150 mab. The action of certain benthic fauna that are exclusively associated with the DWC ecosystem (e.g. echiuran worms) leads to the subduction of fresh organic material into the sediments. The mound surface sediments are enriched in organic carbon, relative to off-mound sites. There is no evidence for hydrocarbon venting at this location.  相似文献   
99.
Resource Management of Precious Corals:   总被引:6,自引:0,他引:6  
Abstract. Precious corals as a group consist of a variety of species which belong to several classes of Anthozoan corals. In general, all are long lived, slow growing and are characterized by slow rates of annual recruitment and adult mortality. In favorable environments, where large beds of commercial quantity exist, their life history parameters often approximate steady state. In such instances, fishery management models in which the assumption of steady state is explicit, can be applied to their management. In this paper, the history and ecology of precious corals are reviewed in light of modern attempts of resource management using fishery models. In Hawaii, the BEVERTON and HOLT model has been adapted for the management of black, pink and gold coral species. The application of this model as it applies to precious corals is described and an example is given illustrating that it can also be used for shallow water reef building corals which form discrete colonies.  相似文献   
100.
The Skeleton Eroding Band Disease on Coral Reefs of Aqaba, Red Sea   总被引:6,自引:0,他引:6  
Abstract.  The occurrence and distribution of the coral disease Skeleton Eroding Band (SEB) has been studied at the Jordanian coast in the Gulf of Aqaba, the northernmost extension of the Red Sea. The SEB syndrome is caused by the colonial, heterotrich ciliate Halofolliculina corallasia : an advancing front of these protists destroys polyps, coenosarc, and surface of the coenosteum. In recent years SEB was registered in reefs of Australia, Mauritius, and the Red Sea. Along the Jordanian coast, disease frequency at four study sites was investigated and afflicted coral genera and species were documented. The study sites were MSS (Marine Science Station)-north, MSS-south, the tourist area near the middle of the coast, and the industrial area adjacent to the Saudi Arabian border. Corals and infections were counted inside randomly placed 1 m2 frames in reef flats and in 5, 10, and 15 m depths. In order of increasing affectedness of sample sites, MSS-south was the healthiest (12%, 4%, 4%, 16% of infected corals from shallow to deep), followed by MSS-north (19%, 28%, 24%, 24%), the tourist area (51%, 23%, 16%, 41%), and the industrial area (14%, 30%, 39%, 31%). By far the most frequently encountered coral species were Acropora spp. and Stylophora sp., while relative infection-rates were highest among Seriatopora sp. (75%), as well as Stylophora sp., Hydnophora sp., and Galaxea sp. (50% each). This was followed in steadily decreasing order from 44% to 5% by Pocillopora , Mycedium , Montipora , Echinopora , Acropora , Lobophyllia , Goniastrea , Millepora , Platygyra , Fungia , Favia , Porites , Goniopora , Favites , and Pavona . SEB was found to a depth of 30 m, but may occur even deeper.  相似文献   
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