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291.
The objectives of this study were to analyze the biodiversity of the Traditional Gudeuljang Irrigated Rice Terraces in Cheongsando, South Korea’s representative GIAHS (Globally Important Agricultural Heritage System) site, with reference to position and land-use features, and to develop a plan to promote agricultural biodiversity in the region. We confirmed approximately 54,000 m2 of Gudeuljang paddy fields by an on-site survey. Of the Traditional Gudeuljang Irrigated Rice Terraces confirmed by onsite inspection, our survey showed that approximately 24,000 m2 are currently being used as paddy fields, approximately 15,000 m2 are being used as dry fields, and approximately 14,000 m2 are fallow. In terms of other non-agricultural land use, there was grassland, including graveyards; artificial arboreal land, such as orchards, rivers and wetlands, and man-made facilities, such as roads and residences. We also confirmed that the Traditional Gudeuljang Irrigated Rice Terraces had higher plant species diversity than conventional terraced rice paddies, and there was a difference in life form characteristics between the two types. Although the superficial topsoil structure is the same for the Traditional Gudeuljang Irrigated Rice Terraces (TGIRTs) and conventional terraced rice paddies, it is thought that the differences in the subsurface structure of the TGIRTs contribute greatly to species and habitat diversity. However, the TGIRTs in Cheongsando are facing degeneration, due to damage and reduction in agricultural activity. The main cause is the reduction in the number of farming households due to an aging population in Cheongsando. In order to address this problem, we proposed a management plan, related to fallow paddy fields in South Korea, to initiate voluntary activities in the TGIRTs. 相似文献
292.
In order to elucidate the state of diseases, especially viral diseases, and to prevent viral diseases from occurring in olive flounder hatcheries, a range of studies, including epidemiological study, were performed from 1997 to 2003. The location of the hatcheries investigated includes several representative sites in the east (Kangnung, Uljin, Pohang, Yangsan, Ulsan, Pusan), south (Wando, Changheung, Goheung, Yeosu, Namhae, Tongyeong, Geoje, Jeju) and west (Seosan, Kunsan, Gochang, Yeongkwang, Mokpo, Chindo) costal areas of the Korea Peninsula. A total of 2000 cases have been examined in 7 years, in which mortality caused by viral agents accounts for 22%, or 446 cases. Mortalities associated with viral infection considerably increased from 14% in 1997 to 27% in 2003. A variety of viral diseases were observed, and the occurrences of viral epidermal hyperplasia, viral ascites and viral deformity, viral nervous necrosis, and hirame rhabdoviral disease are 14%, 51%, 25%, and 8% respectively. By investigating the viral infection of broodstock flounder, the infection rate of marine birnavirus (MABV) in hatcheries was identified to be approximately 30%, therefore, it is highly necessary to acquire and keep non-infected broodstock fishes. 相似文献
293.
Sangheon Yi Chang-Gyun Han Keun-Chang Oh In Sun Seo Dongwook Kim Jaeyoung Lee Min Han Hanwoo Choi Jaesoo Lim Sujeong Park Chang-Pyo Jun Taesop Cho 《第四纪科学杂志》2022,37(1):100-113
We comprehensively analyzed sediments obtained from an archeological excavation. A trench sediment profile of Maedun Cave (MC), South Korea, was analyzed geoarchaeologically. Multi-proxy analyses (palynomorphs, grain size, magnetic susceptibility, animal bones and artifacts) reflected the vegetation, hydroclimate and lives of prehistoric people at Marine Isotope Stage (MIS) 3 (ca. 40–30k cal a bp ) in the early Late Paleolithic. The palynoflora consisted of pollen and non-pollen palynomorphs. Under the air-circulation system in the cave, anemophilous pollen flowed in during the day, whereas waterborne pollen and spores, and freshwater algae, were transported by flooding during the summer monsoon rainy season. Mixed conifer and deciduous broad-leaved forest with an understory of pteridophytes flourished around the north-east central Korean Peninsula during MIS 3. Freshwater algae and grass pollen records may reflect precipitation intensity. It is assumed that they had flowed in during flooding caused by high precipitation during the enhanced East Asian summer monsoon, corresponding to Dansgaard–Oeschger (D/O) events 5 and 8 of δ18O GISP2 and Hulu Cave. The prehistoric people hunted herbivorous animals in the area around MC and sheltered inside it seasonally. They also used the grains of oats growing near the dwelling as a source of food. 相似文献