全文获取类型
收费全文 | 391篇 |
免费 | 15篇 |
国内免费 | 29篇 |
专业分类
测绘学 | 8篇 |
大气科学 | 11篇 |
地球物理 | 42篇 |
地质学 | 137篇 |
海洋学 | 15篇 |
天文学 | 2篇 |
综合类 | 12篇 |
自然地理 | 208篇 |
出版年
2023年 | 2篇 |
2022年 | 21篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 26篇 |
2018年 | 18篇 |
2017年 | 28篇 |
2016年 | 19篇 |
2015年 | 23篇 |
2014年 | 14篇 |
2013年 | 45篇 |
2012年 | 9篇 |
2011年 | 14篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 21篇 |
2007年 | 12篇 |
2006年 | 22篇 |
2005年 | 8篇 |
2004年 | 13篇 |
2003年 | 6篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 10篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1980年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有435条查询结果,搜索用时 312 毫秒
61.
伴随着“文化转向”与“再物质化”思潮的出现,物质地理学已经成为西方社会文化地理研究中新兴且活跃的研究分支之一,而追踪物质(following the things)是物质地理学中重要的方法论视角,它强调人文地理学所重视的“流动性”,通过追踪特定物质在流动过程中物质性的变化以及能动性,揭示物质流动中的社会关系与文化意义。论文通过梳理和分析西方学界中物质地理学的相关文献,阐述了近年来的研究进展,同时指出现阶段在追踪物质视角下该领域的主要议题为:物质的象征研究、物质与认同研究、生产与消费研究以及权力博弈与协商研究等内容。最后,论文归纳总结了当下物质地理学存在的研究局限与空白,展望了未来中国物质地理学研究可进一步探索的话题与方向,以期打开未来中国与西方国家物质地理学的对话窗口。 相似文献
62.
针对当前国内对人口流动空间分布问题常采用的单一指标以及数理统计方法、忽略了空间效应、很难正确识别人口流动地域类型以及空间分布模式的问题,提出了一种以县域以人口净迁移率为横坐标和以人口总迁移率为纵坐标的复合指标法。首先对2010-2013年福建省85个县域的人口流动地域类型进行了测度和划分;随后,为进一步探索人口流动集聚程度,采用探索性空间数据分析方法进行了量化分析。结果表明:福建省县域人口流动空间分布差异显著;福建省县域人口流动的地理集聚特征显著且存在明显的正相关关系,并且"低-低"类型分布占据主要地位。研究结果为发现福建省县域人口流动空间模式,更好地为人口流动区域差异进行量化分析提供了强有力的支撑。 相似文献
63.
Laure Charleux 《The Professional geographer》2018,70(2):186-197
This article proposes a simple post hoc segmentation approach to revisit Household Travel Survey data and sketch archetypal mobility figures (clusters) that relate to people's daily mobility experiences. Describing the mobility behaviors of the different clusters and the distribution of the population between clusters is a powerful means to draw the mobility landscape of a metropolitan area and make comparisons over time and across places. Furthermore, clusters can be used to contextualize mobility behaviors in a variety of social inquiries and can be complementary to traditional quantitative mobility indicators or qualitative investigations. 相似文献
64.
Shaolu Yu 《Urban geography》2018,39(4):563-586
Based on the ethnographic research and in-depth interviews in Flushing, Queens, New York City, this paper proposes the concept of mobilocality. Mobilocality provides a conceptual framework to examine the urban ethnic communities through the lens of mobility from a multi-scalar perspective. Mobilocality is formed by the paradox of transnational mobility and local immobility that are simultaneously embedded in everyday life of (im)migrants. It is through mobilocality where individual is ethnic, ethnic is transnational, transnational is urban. This article also suggests a placed and contextual understanding of mobility by illustrating the interrelationships among the four spatialities: mobility, place, scale and distance. The making of mobilocality is an outcome of the dialectal process among these spatialities, which involves not only spatial-temporal dimensions, but also social and cultural context. Transnationalism is far from a celebration of cosmopolitanism and diversity. Rather, it is a divergent process that generates heterogeneity and boundaries, a product of time-space distortion instead of time-space compression. 相似文献
65.
Chinese overseas industrial parks in Southeast Asia: An examination of policy mobility from the perspective of embeddedness 总被引:4,自引:2,他引:2
The development of overseas industrial parks is a key component of the Belt and Road Initiative and an expected experimental way of promoting inclusive globalization by inventing new forms of cooperation between China and local host countries. Policy mobility, a classic theory within international political geography addressing the connection between local and global policies, has implications for overseas industrial parks development. In this paper, we argue that policies are not easily moved directly from one place to another; instead, policies are embedded due to the role of local actors in policy mobility. This article first provides an overview of seven China-Southeast Asia economic and trade cooperation zones identified by the Ministry of Commerce, and analyzes their key participants. It then discusses policy mobility by looking into the roles of revenue, land, and talent in developing these industrial parks. The paper finds that these parks face challenges, such as the complicated geographical environments of host countries, huge pressure from enterprise investment capital, the lack of overseas service platforms, and underdeveloped agglomeration economies. In the light of the current situation, policy suggestions for the future sustainable development of overseas industrial parks are put forward. 相似文献
66.
Mobility Sequence of Chemical Elements During Loess Weathering—Pedogenesis,Weinan,Shaanxi Province,China 总被引:1,自引:1,他引:0
The distribution of chemical elements in the Weinan loess section shows that: (1) carbonate is the critical constituent affecting
loess chemistry. The leaching of carbonates may cause “apparent” enrichment of some other constituents. (2) CaCO3, SiO2, FeO, MgO, K2O and Na2O are mobile while Al2O3, Fe2O3 and TiO2 are inert components. The mobility sequence may follow the order of CaCO3>FeO>MgO>Na2O>K2O>SiO2>Al2O3>TiO2>Fe2O3. (3) No obvious migration is noticed of iron, except changes in valence and forms, during the pedogenic process. Little iron
has been supplied to paleosol from precipitation. (4) Carbonates and, to a lesser extent, iron are most sensitive to, and
can be therefore used as good indicators of, environmental changes.
This research project was financially supported by the National Natural Science Foundation of China (Grant No. 49672137). 相似文献
67.
68.
利用频谱分解得到的频率能量数据体进行属性提取,是烃类检测的常用手段之一.同步挤压小波变换能够提供高分辨率的时频谱,具有较好的应用潜力.本文以同步挤压小波变换为基础,提出了一套烃类检测方法,包括低频阴影检测、流体流动性估计以及高频能量衰减等,通过自适应选取优势频段,实现了多属性联合高精度刻画烃类的分布范围.实际资料处理结果与现有钻井情况吻合,具有较好的实用性,实现了对储层位置的高精度描述,对指导油气田开发具有重要的理论意义和实用价值. 相似文献
69.
Occurrence of baddeleyite (ZrO2) which is a rare mineral has been recorded in ferromanganese
nodules of Central Indian Ocean Basin (CIOB). The mineral occurs either as independent isolated
sub-rounded to elliptical grains or in clusters forming fine subhedral crystals (<3 mm) within ferromanganese
concretionary growth bands. The mode of occurrence, textural features and chemistry of the
mineral suggest detrital and possibly an authigenic origin for baddeleyite. For authigenic origin it is
proposed that zirconium might have got released either from the terrigenous sediments or the altered
seafloor rocks forming halogen complexes and subsequently it has re-precipitated in the form of baddeleyite
within manganese nodules under oxic to sub-oxic conditions. 相似文献
70.
Geochemistry and mineralogy of shallow alluvial aquifers in Daudkandi upazila in the Meghna flood plain, Bangladesh 总被引:1,自引:0,他引:1
M. Aziz Hasan Mattias von Br?mssen Prosun Bhattacharya Kazi Matin Ahmed Arif Mohiuddin Sikder Gunnar Jacks Ondra Sracek 《Environmental Geology》2009,57(3):499-511
The shallow alluvial aquifers of the delta plains and flood plains of Bangladesh, comprises about 70% of total land area are
mostly affected by elevated concentrations of arsenic (As) in groundwater exposing a population of more than 35 million to
As toxicity. Geochemical studies of shallow alluvial aquifer in the Meghna flood plain show that the uppermost yellowish grey
sediment is low in As (1.03 mg/kg) compared to the lower dark grey to black sediment (5.24 mg/kg) rich in mica and organic
matter. Sequential extraction data show that solid phase As bound to poorly crystalline and amorphous metal (Fe, Mn, Al)-oxyhydroxides
is dominant in the grey to dark grey sediment and reaches its maximum level (3.05 mg/kg) in the mica rich layers. Amount of
As bound to sulphides and organic matter also peaks in the dark grey to black sediment. Vertical distributions of major elements
determined by X-ray fluorescence (XRF) show that iron (Fe2O3), aluminum (Al2O3) and manganese (MnO) follow the general trend of distribution of As in the sediments. Concentrations of As, Mn, Fe, HCO3
−, SO4
2− and NO3
− in groundwater reflect the redox status of the aquifer and are consistent with solid phase geochemistry. Mineralogical analysis
by X-ray diffraction (XRD) and scanning electron microscopy (SEM) fitted with energy dispersive X-ray spectrometer (EDS) revealed
dominance of crystalline iron oxides and hydroxides like magnetite, hematite and goethite in the oxidised yellowish grey sediment.
Amorphous Fe-oxyhydroxides identified as grain coating in the mica and organic matter rich sediment suggests weathering of
biotite is playing a critical role as the source of Fe(III)-oxyhydroxides which in turn act as sink for As. Presence of authigenic
pyrite in the dark grey sediment indicates active reduction in the aquifer. 相似文献