全文获取类型
收费全文 | 77篇 |
免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 9篇 |
地球物理 | 23篇 |
地质学 | 26篇 |
海洋学 | 9篇 |
天文学 | 7篇 |
自然地理 | 3篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有78条查询结果,搜索用时 46 毫秒
61.
Jonathan P. Fleming John D. MadsenEric D. Dibble 《Applied geography (Sevenoaks, England)》2012,32(2):629-635
Diverse native aquatic macrophytes serve a number of physical and biological functions in the aquatic environment and provide essential habitat for several fish species. In systems that lack submersed macrophytes, native macrophyte re-establishment can be used to revitalize the aquatic community. Planning re-establishment projects requires knowledge of the system along with the growth requirements of macrophytes. Prior studies have identified factors that are important for macrophyte colonization, persistence, and dispersal. However, deductive approaches to identify macrophyte habitat that is suitable for management application have not been developed. A potential solution to this problem is the incorporation of waterscape-wide variables into a Geographic Information System (GIS) and the use of spatial modeling techniques to identify suitable macrophyte habitat. This provides a scientifically based approach to macrophyte re-establishment planning to make efforts more efficient and to recognize potential coverage. The flexibility, scalability, and topological advantages of using a GIS to identify and visualize habitat allow integration with other spatial ecological variables to improve the management of aquatic resources from plants to fish, including invasive species mitigation. Using Little Bear Creek Reservoir, Alabama, as an example system, we illustrate a GIS modeling process that can be applied to any system where the identification of macrophyte habitat is relevant to aquatic resource management goals. 相似文献
62.
The migmatites of the Palmer area, in the core of the Mt Lofty Ranges metamorphic belt, are considered to have formed by partial melting of quartzo‐feldspathic schists and gneisses, rather than by metamorphic segregation as formerly suggested. Large‐ and small‐scale tectonic structures indicate that the Cambrian Kanmantoo Group rocks in the Palmer area have undergone three deformations during the Delamerian Orogeny and that these are similar to those described elsewhere in the Mt Lofty Ranges. The relationships of the migmatitic veins to these structures indicate that some partial melt was present during a large part of the structural history: some veins formed before and after the first folding event, and some formed during or after the third folding event even though the metamorphic grade appears to have been waning in areas more distant from the highest grade ore. The early onset of partial melting is consistent with previously reported evidence that thermal activity in the belt began before penetrative deformation. 相似文献
63.
Edward J. Fleming Carl T.E. Stevenson Michael S. Petronis 《Proceedings of the Geologists' Association. Geologists' Association》2013
North Norfolk is a classic area for the study of glacial sediments with a complex glaciotectonic deformational history, but the processes leading to the formation of some structures can be ambiguous. Anisotropy of magnetic susceptibility (AMS) analyses, providing quantitative fabric data, have been combined with the analysis of visible structures and applied to the Bacton Green Till Member, exposed at Bacton, Norfolk. Thermomagnetic curves, low temperature susceptibility and acquisition of isothermal remanent magnetism (IRM) reveal that the magnetic mineralogy is dominated by paramagnetic phases. The magnetic foliation is parallel to fold axial planes and weakly inclined to bedding, whilst the magnetic lineation is orientated parallel to stretching, indicated by the presence of stretching lineations and the trend of sheath folds. Variations in the orientation of the magnetic lineation suggest that the Bacton section has been subject to polyphase deformation. After subaqueous deposition, the sequence was overridden by ice and glaciotectonically deformed which involved stretching initially north–south, then east–west. These results show that AMS can be used to detect strain in three dimensions through a glaciotectonite where paramagnetic mineralogy is dominant. This approach therefore provides further support to the use of AMS as a fast, objective and accurate method of examining strain within deformed glacial sediments. 相似文献
64.
An assemblage of Early Ordovician dichograptids has been discovered in a spotted slate from the Omeo Metamorphic Complex just north of Eskdale in northeast Victoria. Identifiable species present are Tetragraptus fruticosus (4 br.), T. acclinans, and Didymograptus cf. D. ensjoensis. Together these indicate an age corresponding to zone Bel of the early Bendigonian. They are therefore the first recorded fossils of pre‐Darriwilian age discovered east of the Howqua Zone in Victoria. The depositional history of the Wagga Trough is thus demonstrated to have commenced at least early in the Ordovician, rather than in the late Middle Ordovician as previously thought. 相似文献
65.
66.
67.
As mining expands throughout the world, a growing body of literature is focusing on the relationship between mining and well-being in locations where resource extraction occurs. Although many topics such as employment and migration have been researched, the impacts of mining on income inequality have received less attention from scholars. Income inequality is a highly debated topic and the Gini coefficient (GC) one of the most popular indicators used to measure and discuss it. In this paper we estimate GCs for all sub-State regions of Australia and analyse their changes during the ‘mining boom decade’ (2001–11) across mining and non-mining regions. Our results show that, on average, income inequality increased by around 4.8 per cent in mining regions, compared to 8.7 per cent in the average non-mining region. However, the results also show important variation in changes of GC across mining regions, suggesting that the industry is likely to affect the distribution of local incomes in different ways. The method we propose to estimate GCs for regional areas and the results obtained across mining and non-mining regions provide important insights for future research and for regional policy makers, especially those concerned with the socio-economic impacts of industries such as mining across regions. 相似文献
68.
S.E. Park N.A. Marshall E. Jakku A.M. Dowd S.M. Howden E. Mendham A. Fleming 《Global Environmental Change》2012,22(1):115-126
Transformative actions are increasingly being required to address changes in climate. As an aid to understanding and supporting informed decision-making regarding transformative change, we draw on theories from both the resilience and vulnerability literature to produce the Adaptation Action Cycles concept and applied framework. The resulting Adaptation Action Cycles provides a novel conceptualisation of incremental and transformative adaptation as a continuous process depicted by two concentric and distinct, yet linked, action learning cycles. Each cycle represents four stages in the decision-making process, which are considered to be undertaken over relatively short timeframes. The concept is translated into an applied framework by adopting a contextual, actor-focused suite of questions at each of the four stages. This approach compliments existing theories of transition and transformation by operationalising assessments at the individual and enterprise level. Empirical validation of the concept was conducted by collaborating with members of the Australian wine industry to assess their decisions and actions taken in response to climate change. The contiguous stages represented in the Adaptation Action Cycles aptly reflected the diverse range of decision-making and action pathways taken in recent years by those interviewed. Results suggest that incremental adaptation decision-making processes have distinct characteristics, compared with those used in transformative adaptation. We provide empirical data to support past propositions suggesting dependent relationships operate between incremental and transformative scales of adaptation. 相似文献
69.
70.