全文获取类型
收费全文 | 63篇 |
免费 | 5篇 |
出版年
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有68条查询结果,搜索用时 15 毫秒
1.
Geographical variables generally show spatially structured patterns corresponding to intrinsic characteristics of the environment. The size of the sampling unit has a critical effect on our perception of phenomena and is closely related to the variance and correlation structure of the data. Geostatistical theory uses analytical relationships for change of support (change of sampling unit size), allowing prediction of the variance and autocorrelation structure that would be observed if a survey was conducted using different sampling unit sizes. To check the geostatistical predictions, we use a test case about tree density in the tropical rain forest of the Pasoh Reserve, Malaysia. This data set contains exhaustive information about individual tree locations, so it allows us to simulate and compare various sampling designs. The original data set was reorganized to compute tree densities for 5 times 5-, 10 times 10-, and 20 times 20-meter quadrat sizes. Based upon the 5 times 5-meter data set, the spatial structure is modeled using a nugget effect (white noise) plus an exponential model. The change of support relationships, using within-quadrat variances inferred from the variogram model, predict the spatial autocorrelation structure and new variances corresponding to 10 times 10-meter and 20 times 20-meter quadrats. The theoretical and empirical results agreed closely, whereas neglecting the autocorrelation structure would have led to largely underestimating the variance. As the quadrat size increases, the range of autocorrelation increases, while the variance and the proportion of noise in the data decrease. 相似文献
2.
3.
4.
5.
Suzanne Marchand 《History of European Ideas》2016,42(6):808-818
SUMMARYThis essay discusses Hans Aarsleff's long battle to demonstrate the importance of the French and British thinkers of the mid-eighteenth century to the development of modern linguistic thought. Contesting claims that German scholars were the first to develop historicised theories of language, Aarsleff, along with his Princeton colleagues Lionel Gossman and Anthony Grafton, helped pioneer longue durée studies of the history of philology and of historiography that cross national boundaries as well as the so-called Sattelzeit (stretching from about 1780 until 1820). Although the importance of his work was, for a long time, little appreciated by modern intellectual historians, this essay argues that it is time that we fully learned Aarsleff's lessons. 相似文献
6.
Suzanne Marchand 《History and theory》2020,59(3):482-489
This review of John Potts's Ideas in Time: The Longue Durée in Intellectual History discusses the advantages and disadvantages of writing intellectual histories that embrace the longue durée. It applauds Potts's concise account of historiographical discussions of continuity and discontinuity in the history of ideas in the last seventy-five years but laments his failure to discuss the contributions of historians of science and scholarship to the practices of knowledge-making and to the transmission of ideas. It suggests that the study of discontinuities can also be rich and revealing, and it proposes one approach to understanding the ways in which ideas go out of fashion. It concludes by noting, first, that the models that contemporary historians of ideas adopt also have to do with book-market opportunities and pressures and, second, that we have work to do to engage our contemporaries and students in whatever form of intellectual history we choose to write. 相似文献
7.
8.
9.
10.