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11.
以中国343个地级及以上行政单元为研究对象,运用数据包络分析和探索性空间数据分析,研究了2001年和2011年 “四化”协调发展及其效率的空间差异变化,借助地理加权回归模型揭示“四化”协调发展效率的影响因素及其空间差异。结果显示,中国地级单元2001年和2011年的“四化”协调发展及其效率均存在显著的空间分异,综合指数、耦合度和协调度空间差异呈现以西北-东南走向的“反胡焕庸线”为分界的态势。“四化”协调发展效率整体较低,效率值较高的地区集中在中部地区,达到“有效”状态的城市极少。10 a间平均效率值总体降低 ,高值区逐渐向东部沿海地区转移。城乡人均固定资产投资差异、人均GDP和人均社会消费品零售总额是影响“四化”协调发展效率的重要因素。  相似文献   
12.
当代中国的全球观念与全球战略   总被引:11,自引:4,他引:7  
陆大道 《地理科学》2016,36(4):483-490
简要叙述了“一带一路”战略对于中国崛起的重大意义,分析了当今全球地缘政治的基本格局、重要区域(国家)的地缘政治倾向及与中国发展经贸和产能合作可能的前景,指出了“一带一路”战略实施中可能将遇到的问题,并就加强“一带一路”研究及资料收集、整理、管理工作提了建议。  相似文献   
13.
Whether the September 5, 2022, Luding MS6.8 earthquake is an ‘expected’ event in the context of earthquake forecast? This commentary discusses this issue mainly using the recently proposed ‘earthquake nowcasting’ approach.  相似文献   
14.
湖南"3+5"城市群城市综合承载力评价从人口、经济、资源、环境、城市基础设施以及外部支撑力6个方面入手,所采用方法为信息熵法。结果表明"3+5"城市群城市综合承载力呈现出明显的梯度差异,长沙市以综合得分1.715分居于城市群之首,益阳市为1.410分最低,且"3+5"城市群承载力总体状况不容乐观;经济承载力是制约城市群城市综合承载力提高的首要因素;资源、环境承载力低下成为城市群共同问题;科技创新与区际交流对城市综合承载力提升具有重要意义。  相似文献   
15.
熊国庆  蔡习尧  伍皓  江新胜 《地质通报》2009,28(10):1448-1457
对藏南发育完整的、厚度巨大的海相白垩纪地层中的暗色泥、页岩开展了有机质丰度研究。综合分析结果表明:该区泥、页岩中残余有机碳含量在0.05%~1.1%之间,平均值约为0.42%,其中下白垩统约为0.531%,上白垩统约为0.265%,有机碳平均含量变化特征与该区的古地理格局及海平面升降有关。氯仿沥青‘A’含量在0.0009%~0.0072%之间,平均含量约为0.0040%。有机碳与氯仿沥青‘A’最大值与最小值之比分别为22和8。有机碳与氯仿沥青‘A’这种弱负相关性与两者遭受剧烈的地表风化作用、强烈的紫外线照射和高程度有机质热演化后的损失量有关,后者远大于前者。白垩系残余有机碳含量大于0.6%的中等—好生油岩样10件,占样品总数的27%,下白垩统样品9件,占样品总数的24.3%,上白垩统样品1件,占样品总数的2.7%,表明来自北喜马拉雅地区东山组和康马—隆子地区甲不拉组的早白垩世泥、页岩为该区主要的有效生油岩。  相似文献   
16.
尼洋河流域是雅鲁藏布江第四大支流,受冰川、积雪和冻土影响,水循环关系极其复杂。为深入研究该区域内的水文循环过程,本文在寒区水循环模型(WEP-COR)的基础上,针对青藏高原气候和地质特点,构建了耦合“积雪-土壤-砂砾石层”连续体和“积雪-冰川”水热过程模拟的青藏高原分布式水循环模型(WEP-QTP)。在尼洋河流域通过对2013—2016年的流量过程模拟发现,工布江达和泥曲站的逐月流量Nash-Sutcliffe效率系数分别达到0.810和0.752,比改进前的0.430和0.095有明显提升;以2015年为例,对比WEP-COR和WEP-QTP模型发现,WEP-QTP模型在汛期特别是主汛前(冻土融化期)模拟的流量过程不会出现较大的波动,模拟得到的逐日流量Nash-Sutcliffe效率系数相比WEP-COR从-0.67提高到0.54。模型增强了地下水含水层的调节作用,使得流量过程更加平稳且接近实测,研究结果表明,WEP-QTP模型适用于青藏高原的水文模拟。  相似文献   
17.
This exercise in a type of applied historiography begins by annotating aspects of reform in Western education from the 1880s to the 1930s, an interval which exhibits the responses of ‘new’ subjects to political and social demands for improved civics education, and encompasses the inauguration of a recognisably ‘academic’ geography in Australia. Designedly, since the nominated period also incorporates the early life and career of pioneering geographer Griffith Taylor, the discussion probes beneath the strata of obfuscatory generalisation to relate one individual's engagement with the vortex of change. More specifically, it extracts a few lessons from Taylor's approach to ‘Nation‐Planning’ to suggest an appropriate orientation to current reformism in Australian education. It is argued that, while this trend questions the civic utility of established disciplines, it has been badly served by a disturbing ignorance of the social and intellectual heritage of the subjects under challenge.  相似文献   
18.
Abstract

Formation of electric current sheets in the corona is thought to play an important role in solar flares, prominences and coronal heating. It is therefore of great interest to identify magnetic field geometries whose evolution leads to variations in B over small length-scales. This paper considers a uniform field B 0[zcirc], line-tied to rigid plates z = ±l, which are then subject to in-plane displacements modeling the effect of photospheric motion. The force-free field equations are formulated in terms of field-line displacements, and when the imposed plate motion is a linear function of position, these reduce to a 4 × 4 system of nonlinear, second-order ordinary differential equations. Simple analytic solutions are derived for the cases of plate rotation and shear, which both tend to form singularities in certain parameter limits. In the case of plate shear there are two solution branches—a simple example of non-uniqueness.  相似文献   
19.
Statistical models poorly predict bacteria in near-shore environments of tropical islands due to inaccuracies in runoff and discharge characterization of storm events. Intense, short duration storms on small, steeply sloped watersheds produce high rates of runoff, resulting in rapid pulses of discharge that influence the physical and physiological conditions of the fate and transport of pathogens. As such, increasing rates of discharge are expected to have a different influence on sediment transport and pathogen load compared to decreasing rates of discharge. Regression modeling was used to examine the affect of antecedent streamflow on the interaction between environmental parameters and two fecal indicator bacteria, enterococci and Clostridium perfringens. Including the relative change in discharge incorporates a proximate representation of the energy available to transport particulates, improving predictions of near-shore water quality. Understanding factors that influence pathogen loads improves management of watersheds and protects public health.  相似文献   
20.
This paper deals with the scientific assessment of the physical properties of sandstone used in the conservation of Sydney's historic heritage sandstone buildings. The local Hawkesbury Sandstone has been widely used for all manner of constructions since the early days of the first settlement. In the nineteenth century, dimension sandstone quarries existed all over the Sydney region, and the demand for the stone was great. During this time, a true ‘freestone’ known as ‘yellow block’ sandstone, in which bedding planes were absent, was quarried extensively. This sandstone is also known as a ‘self-colouring’ sandstone, where the rock, although grey when quarried, turns a yellow–brown after a few months exposure to the atmosphere. It can be easily carved and was eminently suitable for the ornate Victorian architecture of the time. There are very few quarries within the Sydney region today capable of producing ‘yellow block’ sandstone. Whenever possible, sandstone from suitable building excavations, particularly on the Pyrmont Peninsula, is used for this work. Conservation work is extremely expensive and the building elements that most need replacement, the overhanging and decorative elements, are usually those that cost the most. It is essential that the most durable replacement stone be selected. Thus, a strict regime of scientific testing is used for any major conservation project, in order to determine the physical properties of possible replacement stone. This is the province of the geologist and involves visual observation in the quarry or excavation, which is a simple, cost-effective means of weeding out poor quality stones, followed by laboratory engineering tests to establish the physical parameters of a sandstone and finally, petrographic analysis. The results of such tests, combined with careful sampling, ensure the best possible quality of replacement material.  相似文献   
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