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101.
利用澳大利亚海平面气压和中国夏季气温站点资料,使用SVD和线性回归方法揭示了澳大利亚高压(以下简称澳高)的年际变化与中国夏季气温异常的联系。结果表明,SVD的第一模态(简称SVD1)时间系数与通常使用澳高指数相关可达到0.97。SVD1表示出澳大利亚高压的年际变化与中国江南地区夏季气温存在密切联系。澳高增强(减弱)时,江南地区夏季气温偏低(偏高)。整层垂直积分大气加热场、海平面气压场、500hPa的高度场变化以及降水和总云量的变化都对夏季气温的形成有一定作用。澳高对中国夏季气温的可能影响途径为:澳高强(弱)年时,澳大利亚地区低层的异常辐散风场在菲律宾东侧的暖池附近产生辐合(辐散),引起正(负)涡度源,激发P-J型波列,伴随着在南海-西太平洋地区产生副高正异常(负异常),导致副高偏西(偏东),进而增强(减弱)来自孟加拉湾的水汽输送,同时江南地区水汽和异常风场辐合(辐散),有利于(不利于)该地区降水异常的发生和维持,有益于气温降低(升高)。  相似文献   
102.
Some economists have questioned the need for retaining boat licences in fisheries managed through rights-based systems on the assumption that licences act as an impediment to autonomous adjustment. In this paper, the role of boat licences in fisheries managed through rights-based instruments is explored through examining their use in several fisheries in Australian and elsewhere. The study concludes that any impediment to autonomous adjustment that is produced by boat licences is likely to be small relative to other factors. Further, boat licences play an important role in offsetting imperfections in the rights-based management systems that exist in most countries.  相似文献   
103.
澳大利亚前寒武纪地质演化与超大陆旋回密切相关,大多数地质和成矿事件与超大陆聚合、裂解有关。自太古代以来,澳大利亚大陆主要由西向东生长。澳大利亚早前寒武纪古陆核为太古代皮尔巴拉和伊尔岗克拉通,古元古代—中元古代时南北克拉通和西澳大利亚克拉通在哥伦比亚超大陆聚合时拼贴在一起,并在其后的罗迪尼亚超大陆演化过程中最终形成澳大利亚中西部的前寒武纪克拉通。澳大利亚前寒武纪成矿作用与克拉通构造演化和超大陆旋回有关,与绿岩带有关的造山型金矿是凯诺兰大陆聚合过程中的产物,而沉积岩容矿的铅锌矿床、不整合面型铀矿、铁氧化物型铜金矿床则在哥伦比亚超大陆裂解过程中形成。不同超大陆聚散过程中表现出不同的成矿特征,为今后的矿产勘查提供了丰富的信息。  相似文献   
104.
Knowing where sports talent is produced is fundamental to identifying spatial factors in talent production and to assist with talent identification. This research develops spatial analysis methods—the ‘Talent Tracker’—to harness geographical information systems and identify regions that are over- and under-producing sports talent. The approach focuses on the professional Australian Football League (AFL), using data sourced from the AFL itself and other sources, to identify differences in regional ‘talent yield’ based on junior participation. Data from AFL draft records, informants and secondary sources identified the place of junior talent development for the 1290 players who were drafted and played at least one game of senior AFL football in the period 1997–2010. AFL national census data identified junior participation for 94 specified regions for the period 2002–09. AFL talent was assigned to these regions by using ArcGIS procedures, and the datasets synthesised to produce tables and maps of talent yield by participation for each of the 94 AFL regions. The results demonstrate the power of contemporary spatial analysis to open up new research methods for studies into sports talent production and identification. Clear spatial patterns emerge in talent yield at both the national and metropolitan scales. The results provide numerous avenues for further research to explore determining factors for the spatial patterns identified.  相似文献   
105.
Sediments from ODP Site 1128 in the Great Australian Bight record isotopic and mineralogic variations corresponding to orbital parameters and regional climate change during the early Oligocene climate transition and Oi1 glacial event. Bulk carbonate stable isotope analyses reveal prominent positive oxygen and carbon isotope shifts related to the inferred major increase in glaciation at approximately 33.6 to 33.48 Ma. The oxygen isotope excursion corresponds to a prolonged period of low eccentricity, suggesting ice-sheet growth during low seasonality conditions. The clay mineralogy is dominated by smectite throughout. The exclusive occurrence of highly crystalline smectite from 33.6 to 33.5 Ma suggests the occurrence of explosive volcanism that correlates with the positive oxygen isotope shift. The dominance of mixed-layer smectite from 33.5 to 33.4 Ma and an increase in illite following 33.4 Ma indicates a transition from cool, wet conditions to cool, dry conditions over Australia during the Oi1 glaciation. Clay mineralogy and carbonate percentages reveal precession-scale oscillations during the Oi1 event. Kaolinite varies inversely with smectite and percent carbonate. Variations in precipitation and runoff, and wind velocities during southern hemisphere summer perihelion and high eccentricity intervals may account for the precession-scale oscillations.  相似文献   
106.
107.
孙淑清  刘舸  张庆云 《大气科学》2007,31(6):1189-1200
利用中国气象局提供的热带气旋资料、NCEP/NCAR再分析资料和美国NOAA向外长波辐射(OLR)等资料, 研究了西太平洋(125°E~150°E)夏季热带气旋生成频数多寡的可能机理, 讨论了南北半球环流系统共同作用的物理过程及其对热带辐合带(Intertropical Convergence Zone, 简称ITCZ), 进而对热带气旋频数的影响, 并重点探论了从澳大利亚东侧位势高度异常到北半球西太平洋热带气旋频数响应的可能物理过程。研究发现: 澳大利亚东侧的环流异常和西太平洋热带气旋活动频数密切相关。南半球的澳大利亚东侧环流异常可能不完全是通过越赤道气流, 而主要是通过Rossby波的传播造成的南北半球遥相关作用, 影响北半球环流系统的, 进而影响菲律宾以东赤道辐合带对流活动的强弱, 导致西太平洋热带气旋生成频数的多寡差异。当澳大利亚东侧的位势高度为正距平时, 相应地在菲律宾以东地区也会出现正距平。即西太平洋副高偏强, 且偏南西伸, 抑制热带辐合带的对流活动发展, 使菲律宾以东的对流活动偏弱, 从而使热带气旋生成频数偏少。而当澳大利亚东侧的位势高度为负距平时, 相应地在菲律宾以东地区也会出现负距平。也即西太平洋副高偏弱, 且位置偏北。菲律宾以东地区对流活动偏强, 热带气旋生成频数偏多。另外, 西太平洋 (125°E~150°E) 以西的上游赤道西风也对热带气旋频数也有重要影响。具体表现为, 当90°E附近的越赤道气流强时, (5°N~15°N, 125°E~150°E)范围内的西风也随之加强, 从而使菲律宾以东对流活动加强, 西太平洋热带气旋频数增高。反之, 当该支越赤道气流弱时, 上游赤道西风随之偏弱, 从而造成菲律宾以东对流活动偏弱, 西太平洋热带气旋生成偏少。  相似文献   
108.
西藏扎布耶湖地区三万年以来的花粉记录   总被引:5,自引:0,他引:5  
通过对藏北高原扎布耶湖ZK2钻孔沉积物的花粉记录,揭示了该地区三万年以来植被和气候演变历史。37300-36000aB.P.为森林草原植被,气候温湿,淡水湖时期;约36000-31700aB.P.灌丛草原植物,气候冷干,湖水出现短暂咸化,31700-20800aB.P.森林草原植被,气候温暖湿润,湖面扩大,湖水加深时期,20800-14400aB.P.荒漠植被,气候冷干,湖水咸化,湖面开始缩小,初  相似文献   
109.
This study investigated the connection between the Australian summer monsoon(ASM) and summer precipitation over central China. It was found that,following a weaker-than-normal ASM, the East Asian summer monsoon and western North Pacific subtropical high tend to be stronger, yielding anomalous northward moisture to be transported from the western Pacific to central China. Besides, anomalous upwelling motion emerges over 30–37.5°N, along 110°E. Consequently,significant positive summer precipitation anomalies are located over central China. Further analysis indicated that the boreal winter sea surface temperature(SST) in the Indian Ocean and South China Sea shows positive anomalies in association with a weaker-than-normal ASM. The Indian Ocean warming in boreal winter could persist into the following summer because of its own long memory, emanating a baroclinic Kelvin wave into the Pacific that triggers suppressed convection and an anomalous anticyclone. Besides, the abnormal SST signal in the South China Sea develops eastward with time because of local air-sea interaction, causing summer SST warming in the western Pacific. The SST warming can further affect East Asian atmospheric circulation and precipitation through its impact on convection.  相似文献   
110.
References     
Two well‐defined sequences of earthquakes in South Australia were recorded in January and October 1969, these being associated with main shocks of magnitude ML 4.4 and 4.1 respectively. The events occurred in a region of little previous seismic activity, near the boundary of the Adelaide Geosyncline and the Willyama Block.  相似文献   
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