全文获取类型
收费全文 | 248篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
大气科学 | 10篇 |
地球物理 | 68篇 |
地质学 | 49篇 |
海洋学 | 24篇 |
天文学 | 91篇 |
综合类 | 1篇 |
自然地理 | 9篇 |
出版年
2024年 | 3篇 |
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 11篇 |
2012年 | 7篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 14篇 |
2008年 | 8篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1957年 | 2篇 |
排序方式: 共有252条查询结果,搜索用时 15 毫秒
121.
John Jenkins 《Physics and Chemistry of Minerals》1992,19(3):A4-A4
International Mineralogical Association 16th General Meeting at Pisa, Italy, September 3–8,1994 相似文献
122.
John Jenkins 《Physics and Chemistry of Minerals》1992,19(1):A3-A3
International Mineralogical Association 16th General Meeting at Pisa, Italy, September 3–8, 1994 相似文献
123.
124.
125.
126.
127.
C. D. Jones P. B. Storebø T. Bjorvatten C. J. P. Van Buijtenen A. Sills G. J. Jenkins 《Boundary-Layer Meteorology》1984,28(1-2):89-105
In July 1977 dispersion experiments with air ions as tracer were carried out at Porton in southern England. Each trial lasted about 40 min. The source height was 5 m. Continuous ion production took place in eight trials for source-sensor distances between 10 and 100m. Ion production in 1 s pulses took place in another four trials for source-sensor distances between 10 and 50 m. Two sensors were positioned at a height of 5 m and one sensor at 4 m. The experimental set-up and the weather conditions are described. Tabulated results comprise concentration frequency distributions, as well as auto- and cross-correlations, both for 0.01 and 0.1 s resolution. 相似文献
128.
129.
Jenkins 《Monthly notices of the Royal Astronomical Society》1998,294(1):69-92
Fast guiding may improve the images delivered by telescopes. It may be implemented fairly cheaply and offers an upgrade path to smaller telescopes, which will make them more useful in the 8-m era. However, the detailed performance of a fast guiding system must depend on many parameters and this makes it difficult to assess its precise scientific benefits. This paper provides a comprehensive mathematical framework for calculating the performance of fast guiding systems. A range of models has been calculated that illustrates the benefits for telescopes of various sizes in various wavelength ranges. Three measures of performance have been examined: FWHM, 50 per cent encircled energy diameter and energy concentration in a 0.35-arcsec aperture. Typical gains over natural seeing are found to be in the 20 to 40 per cent range at useful levels of sky coverage. Other things being equal, small telescopes do not benefit as much as large ones from fast guiding. The sensitivity of these benefits to assumptions has also been examined, and this highlights the need to operate in the correct wavelength range for the aperture in question. The largest perturbations to ideal models are likely to be the result of telescope windshake and the outer scale of turbulence. If there is appreciable windshake, fast guiding will yield larger benefits than expected from the natural seeing. A short outer scale (a few hundred metres) will, however, lose most of the gains. 相似文献
130.