全文获取类型
收费全文 | 525篇 |
免费 | 20篇 |
国内免费 | 9篇 |
专业分类
测绘学 | 14篇 |
大气科学 | 23篇 |
地球物理 | 131篇 |
地质学 | 184篇 |
海洋学 | 24篇 |
天文学 | 126篇 |
综合类 | 1篇 |
自然地理 | 51篇 |
出版年
2022年 | 2篇 |
2021年 | 11篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 17篇 |
2017年 | 8篇 |
2016年 | 19篇 |
2015年 | 14篇 |
2014年 | 11篇 |
2013年 | 29篇 |
2012年 | 26篇 |
2011年 | 22篇 |
2010年 | 20篇 |
2009年 | 25篇 |
2008年 | 27篇 |
2007年 | 12篇 |
2006年 | 21篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 19篇 |
2001年 | 10篇 |
2000年 | 18篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有554条查询结果,搜索用时 9 毫秒
41.
Derek L Smith 《The Australian geographer》1995,26(1):61-70
This paper compares pastoralists in South Australia in the nineteenth century with Australian mining companies in the twentieth century as they resist the efforts of government to extract a greater proportion of the wealth created in the exploitation of natural resources. In effect, in both cases the struggle relates to the allocation of economic rent between private and corporate capital on the one hand, and the owners of the resources, the people of Australia, on the other. It is difficult not to be impressed by the similarities in the ideologies, objectives and strategies of these two groups of resource exploiters, separated though they are by over one hundred years. 相似文献
42.
43.
44.
45.
46.
Derek W. Sears Gregory W. Kallemeyn John T. Wasson 《Earth and Planetary Science Letters》1983,62(1):180-192
The concentrations of 25 major, minor and trace elements have been determined in four clasts, a metal-rich inclusion and two dark metal-poor inclusions from the Abee enstatite chondrite. The clasts are heterogeneous, displaying 2-fold enrichments or depletions in some elements. The data suggest that there are two generations of metal, one with low, the other with high concentrations of refractory siderophiles. The other elemental patterns can be understood in terms of variations in the abundance of major minerals. We infer that Sc and Mn are located largely in the niningerite ((Fe,Mg)S), V in the troilite (FeS) and rare earth elements in the oldhamite (CaS).Heterogeneities among the clasts are probably primary, resulting from the accretion-agglomeration process, although shock processes in a regolithic setting remain a possibility provided that they were followed by a period of metamorphism sufficient to erase petrologic evidence.In the dark inclusions the concentrations of the rare earths, Eu excepted, are 4 × higher than mean EH levels; this infers enhanced amounts of CaS. The dark inclusions are low in siderophiles, Sc, Mn, K, Na and Al, implying low amounts of metal, niningerite and feldspar. The origin of the dark inclusions is unclear; they do not appear to be the result of a simple, single-stage process. 相似文献
47.
48.
49.
50.
Derek. L. Smith 《The Australian geographer》1992,23(2):149-163
The cost of overcoming distance has played and continues to play an important role in the evolution of Australia's space‐economy. This paper examines the impact of the ‘friction of distance’, as well as the quality of the resource base, on the settlement and development of Eyre Peninsula in South Australia. A series of maps portraying the spread of pastoralism and then agriculture on Eyre Peninsula reveals clearly the importance of ‘accessibility’ in influencing the pattern and timing of settlement. It was not until well into this century that all the potentially agricultural land in the interior was occupied, for this required the construction of a railway and water pipeline up the centre of the peninsula. 相似文献