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利用2004年夏季台湾海峡南部海域的现场激光粒度仪剖面测量数据,运用海洋食物链的粒径谱理论,分析了悬浮颗粒物的Sheldon谱图和正态化谱图的剖面分布精细结构。横跨台湾海峡沿岸及浅滩外斜上升流的A和B两断面Sheldon粒径谱类型相近,正态化谱图的斜率r的范围从-0.79到-0.65,在明显高于寡营养海域的水平上波动。斜率r的高值带或高变幅带,在上升流系高叶绿素带及叶绿素最大层的周边或前端的呈斑状分布。海洋食物链的粒径谱分析结果支持关于台湾海峡南部上升流生态系高生产力、短食物链和高营养转换效率的宏观认识,并深化对营养转换效率分布精细结构的了解。现场激光粒度仪可发展为探索海洋食物链时空分布精细结构的常备传感器。 相似文献
577.
A model of turbidity maximum maintenance in the Irish Sea 总被引:1,自引:0,他引:1
K.M. Ellis C.E. Binding D.G. Bowers S.E. Jones J.H. Simpson 《Estuarine, Coastal and Shelf Science》2008,76(4):765-774
A two-dimensional model has been developed in order to improve understanding of the processes which interact to maintain the sediment concentrations at an isolated turbidity maximum in the Irish Sea throughout the year. The model comprises two interchangeable populations of particles with different diameters, one of fine cohesive material, the other made up of flocs. Both populations are slow settling, and subject to horizontal diffusion, resuspension, settling, aggregation and disaggregation.The equations used to describe the processes of aggregation and the break-up of flocs in response to sediment concentration and turbulent shear have been developed by the tuning of the model to observations. Due to high turbulent shear at the turbidity maximum, the particles are predominantly fine, while the sediment in the surrounding water is made up of larger flocs. Diffusion of small particles out of the turbidity maximum balanced by the diffusion of aggregated material towards it provides a mechanism for its maintenance. The modelled sediment concentrations at the turbidity maximum can be reproduced year-on-year, with no loss due to diffusive processes. This is achievable with a limited, exhaustible source of material which is not replenished once resuspended.Through comparison with satellite imagery the correlation of the modelled sediment concentrations with observations is investigated, both spatially and temporally. The seasonal cycle is reproduced well by the model with winter and summer concentrations matching those observed. Spatially the model also performs well in both turbid regions and those where the surface sediment load is low. 相似文献
578.
M. Peguero-Icaza L. Sánchez-Velasco M.F. Lavín S.G. Marinone 《Estuarine, Coastal and Shelf Science》2008
Fish larvae and hydrographic data collected in the Gulf of California (GC) in December 2002 are used to describe larval fish assemblages (LFAs) and to explore their relationships with environmental variables (temperature, salinity, dissolved oxygen, fluorescence maximum, ? and superficial chlorophyll a). The Bray–Curtis dissimilarity index defined three LFAs, distributed in areas with distinctly different environmental conditions. The affinity of most of the species with the environmental characteristics of their areas of distribution could be interpreted as an indication that spawning occurred inside those areas. Particle tracking in current fields from a 3D numerical model and connectivity matrices are used to assess larval retention in the LFA areas. The technique is well suited for seas like the GC that have well-defined circulation patterns. On time scales around 30 days, retention (from 56% to 73% of the particles) occurred (1) for the North LFA in the Upper GC, (2) for the Channel-Center LFA in the anticyclone over the Northern GC and in Ballenas Channel, and (3) for the South LFA in the eddy over San Pedro Mártir basin and in the shallow zone off the peninsula. Therefore, the Lagrangian analysis revealed that the observed LFAs have a permanency long enough to allow fish larvae to remain in a favorable environment until they develop motility. The main particle export path (less than 26% of the particles) was from the North to the South LFA, following the anticyclonic main flow and coinciding with the gradient in species number and larval abundance. 相似文献
579.
STUDY ON THE ISOTHERMS OF THE INTERACTION BETWEEN SUSPENDED PARTICLES AND Cu (Ⅱ) IN THE HUANGHE RIVER 总被引:1,自引:0,他引:1
INTRODUCTIONThevariousphysicalandchemicalreactionsthatoccurbetweenthesuspendedparticles,sediments,etc.andheavymetalsinanaturalaquaticsystemplayextremelyimportantpartsincontrollingthedistributionpattern,migrationandtransformationofheavymetalsthere.Since… 相似文献
580.
两种激光粒度仪测量湖泊沉积物粒度结果的对比 总被引:4,自引:1,他引:3
湖泊沉积物粒度参数是湖泊沉积与环境演变研究中常用的环境指标,近年来激光粒度仪的发展和广泛使用更是促进了粒度指标的应用并在很大程度上提高了精度和效率.然而不同的激光粒度仪对于同一样品的测量会得到不同的结果,本文利用两种常见的激光粒度仪测量了西藏纳木错的两支岩芯,并对结果进行了对比分析.从仪器的重现性来看,Mastersizer2000型激光粒度仪要优于LS13320型激光粒度仪,而LS13320型激光粒度仪在对含量较少的细颗粒和粗颗粒的检测效果上优于Mastersizer2000型激光粒度仪;两种仪器得到的粒度参数d(0.1)和d(0.5)无论在变化趋势还是绝对数值上都较为相似,而d(0.9)的差异则较大.对比研究结果为利用湖泊沉积物粒度参数提取古环境信息研究提供了基础依据. 相似文献