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利用历史观测得到的温度剖面数据,通过严格筛选和插值,建立了南海北部的气候态垂向温度剖面。随后,利用回归统计分析的方法构建了海面温度异常(SSTA)、海面高度异常(SSHA)联合扩展温度剖面的经验回归模型,并采用卫星遥感得到的SST和SSH数据扩展了南海北部的三维海洋温度场,其时间分辨率为天,空间分辨率为0.25°×0.25°。通过与观测数据的对比研究,扩展得到的温度场可以较为准确地反映南海北部温度剖面的结构特征,并且能有效地体现出一些中尺度变化过程。结果表明,本研究反演得到的三维温度扩展场是较为可靠的,它可以作为海洋数值模型的初始场,实现现场观测数据和卫星遥感数据的互补,有助于更好地分析南海北部温度场的三维结构及变化特征。 相似文献
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Lisa E. Mayhew Graham E. Lau Tom M. McCollom Sam Webb Alexis S. Templeton 《Applied Geochemistry》2011
Hydrogen gas produced in the subsurface from the hydration of mafic rocks is known to be a major energy source for chemolithotrophic life in extreme environments such as hydrothermal vents. The possibility that in situ anaerobic microorganisms present in the deep subsurface are sustained by low temperature H2-generating water–rock reactions taking place around them is being investigated. Whether the growth and activity of H2-utilizing microbes directly influences aqueous geochemistry, rates of mineral dissolution, and the chemical composition of the alteration products is also being quantitatively evaluated.To explore how microorganisms are affected by water–rock reactions, and how their activity may in turn affect reaction progress, laboratory experiments have been conducted to monitor the growth of a methanogenic Archaea in the presence of H2(g) produced from low temperature water–Fe0–basalt reactions. In these systems, the conversion of Fe(II) to Fe(III) and subsequent hydrolysis of water is responsible for the production of H2(g). To characterize key components of the geochemical system, time series measurements of H2 and CH4 gas concentrations, Fe and Si aqueous concentrations, and spatially resolved synchrotron-based analyses of microscale Fe distribution and speciation were conducted. Culture experiments were compared with an abiotic control to document changes in the geochemistry both in the presence and absence of the methanogen.In the control abiotic batch experiment, H2 was continuously produced, until the headspace became saturated, while in the biotic experiments, microbial consumption of H2 for methanogenesis draws H2 down and produces CH4. Purging the headspace gas reinitiates H2 and CH4 production in abiotic and culture experiments, respectively. Mass balance analysis of the amount of CH4 produced suggests that the total H2 production in microbial experiments does not exceed the abiotic experiment. Soluble Si concentrations, while buffered to relatively constant values, were higher in culture experiments than the abiotic control.Iron(aq) concentrations appear to respond to perturbations of H2 and CH4 gas concentrations in both culture experiments and the abiotic control. A pulse of Fe preceded the rise in either H2 or CH4 production, and as the gas concentrations increased the Fe(aq) decreased. Iron-bearing mineral assemblages change with increasing reaction time and mineral assemblages vary between culture experiments and the abiotic control. These geochemical trends suggest that there are different reaction paths between the culture experiments and the abiotic control.The hydration of mafic rocks is a common geologic reaction and one that has taken place on Earth for the majority of its history and is postulated to occur on Mars. These reactions are important because of their effect on the rheology and geochemistry of the ocean crust. While most often studied at temperatures of ~250 °C, this work suggests that at lower temperatures microorganisms may have a profound effect on what has long been thought to be solely an abiotic reaction, and may produce diagnostic mineral assemblages that will be preserved in the geological record. 相似文献
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基于生态足迹的陕西省适度人口研究 总被引:1,自引:0,他引:1
一个区域生态适度人12的确定取决于区域生态承载力与区域人12对生态资源的需求.首先介绍了生态足迹模型的基本概念和计算方法,其次计算了陕西省1990-2004年的生态足迹和实际利用的生态承载力,并在此基础上估算了陕西省1990~2004年的态适度人口.结果表明:在1990~1998年,陕西省年生态适度人口由2898.9万... 相似文献
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根据湖北江夏国家农业气象观测一级站在最近几年水稻观测中实际遇到的情况以及调查发现,直播水稻已形成不推而广的迅猛发展趋势,作为农业气象观测已不可回避地会遇到直播水稻的生育进程观测问题。由于种植方式的改变,大田植株分布形式也发生了根本的变化,仅以传统的移栽水稻制定的现行《农业气象观测规范》已无法处理好直播水稻的观测问题。为此,笔者依据《农业气象观测规范》,结合实际观测经验,分析直播水稻与移栽水稻的差异以及由此引出的新问题,提出了新的观测处理方法,以供同行探讨。 相似文献