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WANG Rujian & CHEN Ronghua . State Key Laboratory of Marine Geology Tongji University Shanghai China . The Key Laboratory of Submarine Geoscience State Oceanic Administration Hangzhou China 《中国科学D辑(英文版)》2005,48(10)
The Bering Sea, located in the Subarctic Northern Pacific Ocean, plays an important role in the global carbon cycle and modern and past global climatic sys-tems, which originates from a very effective biological pump, indicating much higher biogenic opal produc-tion than calcium carbonate[1]. Measured biological particular fluxes show that the flux in the Bering Sea is twice over that in the open ocean. Thereby, the Ber-ing sea is thought as a CO2 sink[2]. At the same time, the Bering Sea… 相似文献
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Numerical studies of earth surface processes in relation to their environment are one of the central topics in physical geography. However, collinearity between explanatory variables and spatial autocorrelation can hinder the detection of key environmental correlates underlying response–explanatory variables' relationships identified by traditional regression methods. Moreover, conclusions about the potential importance of environmental variables have generally made on analysis conducted only at one spatial scale (resolution). In this study, a variation partitioning method provided a framework to obtain new insights into the relative roles of different factors determining patterned ground activity at multiple spatial resolutions. The variation in the distribution of the sorted and non sorted patterned ground was decomposed into independent and joint effects of relief, soil and spatial variables (geographical location) based on a multi resolution system of 1 ha, 25 ha and 100 ha cells covering in total 100 km2 of a subarctic landscape in northern Finland.The independent effects of relief and soil variables captured the largest fraction of the variation in the non-sorted patterned ground distribution, while relief had a major contribution for sorted patterned ground activity. The independent effect of spatial autocorrelation on sorted patterned ground was higher than that on non-sorted patterned ground. However, a considerable amount of variation in the distribution of both patterned ground types was accounted for by the joint effects of explanatory variables and may thus be causally related to two or all three groups of variables. Our analyses produced often contradicting results at different resolutions. Consequently, this has substantial implications for the study of geomorphological systems, since the choice of resolution can have a major effect on the inferences of analyses. Our results draw attention to the roles of resolution and spatial autocorrelation in the study of geomorphological systems. 相似文献
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西太平洋上层海水溶解甲烷浓度及碳同位素特征研究 总被引:4,自引:0,他引:4
对西太平洋上层海水溶解甲烷浓度的研究结果表明,该海域海水甲烷相对于大气甲烷是强烈过饱和的。甲烷浓度及碳同位素组成特征表明这部分甲烷为生物成因。该海域海-气交换过程中甲烷通量在0.7~10.4nmolm-2s-1,明显高于其它开放海域。 相似文献
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Suspended particles collected from surface seawater during the SEEDS II (Subarctic Iron Experiment for Ecosystem and Dynamics Study II) experiment were analyzed individually using an electron probe X-ray micro analyzer and characterized by size and elemental composition. Their numbers, relative abundances, and relative particle volume all showed clear differences between samples collected inside vs. outside the phytoplankton bloom that developed following the addition of iron. Throughout the study, Si-rich, Ca-rich and Organic particles were dominant and their number increased inside the fertilized patch; these particles accounted for 21%, 13% and 58% of the particles examined, respectively. Si-rich or Ca-rich particles commonly consisted of fragments of diatom frustules and coccolithophorids. There was consistently greater percentage of Ca-rich particles and lower percentage of Si-rich particles inside the patch than outside of it in number, but both types of these particles apparently occupied a larger volume inside the patch than outside of it. Organic particles, that showed having peaks in smaller diameter particles, increased apparently inside the patch with time after iron fertilization. The Organic particles had a more diverse mixture of both bio-related and crustal trace elements than the other types of particles. These results suggest that the increase in suspended particles following the iron enrichment was due to a combination of detrital material and live phytoplankton. 相似文献
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2006年夏季西太平洋热带气旋活动的初步研究 总被引:2,自引:1,他引:1
2006年夏季西太平洋热带气旋活动主要有如下特征:1)生成时间具有明显的阶段性,且强度强,登陆中国数偏多。2)登陆热带气旋有其各自特点。例如 “碧利斯”影响范围大、降水强度大、持续时间长;“桑美”风速大,登陆后迅速减弱。作者针对上述2个特点进行了初步分析。研究发现:1)2006年6月27日~8月31日,来自印度洋的热带西风增强并东推延伸及115~140°E的越赤道气流的加强都有利于热带气旋的生成,并在西太平洋副热带高压北移、季节内振荡(Madden Julian Oscillation,简称MJO)的湿位相、高低层纬向风切变弱和菲律宾以东地区热带辐合带(Intertropical Convengence Zone,简称ITCZ)对流活跃等背景条件配合下,使热带气旋在这一阶段频发。2)2006年夏季水汽含量与供给对登陆热带气旋的影响显著。“碧利斯”和“桑美”的水汽来源不同是造成这两个登陆热带气旋明显差异的重要原因。
相似文献
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黄河上游径流丰枯变化特征及其环流背景 总被引:7,自引:4,他引:3
为了揭示影响黄河上游径流丰枯变化的气候因子,为径流的长期、超长期预报与水资源的规划利用提供依据,利用相关台站的降水、径流观测资料,分析了黄河上游汛期径流的丰枯变化特征及其环流背景.结果表明:黄河上游(唐乃亥以上)流域丰、枯水段基本上是交替出现的,总体上枯水持续时间多于丰水,一个完整的丰枯循环周期大约在18 a左右.黄河上游径流的丰、枯,与大气环流的异常有着非常密切的关系,其中,西太平洋副热带高压偏西、偏强、偏北,青藏高原中部地区有西风槽存在是黄河上游汛期降水偏多、径流偏丰的两个重要因素.因此,基于汛期流量的丰枯与其所对应的环流背景之间的联系,可根据前期环流的演变特征对黄河上游汛期流量的丰枯做出大致预测. 相似文献