全文获取类型
| 收费全文 | 53篇 |
| 免费 | 0篇 |
专业分类
| 测绘学 | 2篇 |
| 大气科学 | 3篇 |
| 地球物理 | 4篇 |
| 地质学 | 4篇 |
| 海洋学 | 6篇 |
| 天文学 | 31篇 |
| 自然地理 | 3篇 |
出版年
| 2019年 | 1篇 |
| 2016年 | 1篇 |
| 2013年 | 2篇 |
| 2012年 | 1篇 |
| 2011年 | 2篇 |
| 2010年 | 1篇 |
| 2008年 | 2篇 |
| 2007年 | 3篇 |
| 2005年 | 8篇 |
| 2004年 | 6篇 |
| 2003年 | 2篇 |
| 2002年 | 1篇 |
| 2001年 | 1篇 |
| 2000年 | 1篇 |
| 1999年 | 1篇 |
| 1997年 | 2篇 |
| 1996年 | 1篇 |
| 1994年 | 1篇 |
| 1984年 | 1篇 |
| 1983年 | 1篇 |
| 1980年 | 2篇 |
| 1978年 | 1篇 |
| 1977年 | 1篇 |
| 1976年 | 1篇 |
| 1975年 | 2篇 |
| 1974年 | 1篇 |
| 1973年 | 2篇 |
| 1972年 | 2篇 |
| 1971年 | 1篇 |
| 1970年 | 1篇 |
排序方式： 共有53条查询结果，搜索用时 15 毫秒
1.
2.
A. Greve 《Solar physics》1973,29(1):263-266
The image degradation due to residual surface inaccuracies of the main optical element of a telescope is compared with the image degradation due to atmospheric turbulence. 相似文献
3.
4.
Youri Lammers Charlotte L. Clarke Christer Ersus Antony G. Brown Mary E. Edwards Ludovic Gielly Haflidi Haflidason Jan Mangerud Emilia Rota John Inge Svendsen Inger Greve Alsos 《Boreas: An International Journal of Quaternary Research》2019,48(2):317-329
While there are extensive macro‐ and microfossil records of a range of plants and animals from the Quaternary, earthworms and their close relatives amongst annelids are not preserved as fossils and therefore the knowledge of their past distributions is limited. This lack of fossils means that clitellate worms (Annelida) are currently underused in palaeoecological research, even though they can provide valuable information about terrestrial and aquatic environmental conditions. Their DNA might be preserved in sediments, which offers an alternative method for detection. Here we analyse lacustrine sediments from lakes in the Polar Urals, Arctic Russia, covering the period 24 000–1300 cal. a BP, and NE Norway, covering 10 700–3300 cal. a BP, using a universal mammal 16S rDNA marker. While mammals were recorded using the marker (reindeer was detected twice in the Polar Urals core at 23 000 and 14 000 cal. a BP, and four times in the Norwegian core at 11 000 cal. a BP and between 3600–3300 cal. a BP), worm extracellular DNA ‘bycatch’ was rather high. In this paper we present the first reported worm detection from ancient DNA. Our results demonstrate that both aquatic and terrestrial clitellates can be identified in late‐Quaternary lacustrine sediments, and the ecological information retrievable from this group warrants further research with a more targeted approach. 相似文献
5.
A. Greve 《Solar physics》1975,44(2):371-382
The Zeeman broadening of high n lines is derived. While in areas of the quiet Sun with field strengths of 1 G the upper boundary of the observable frequency region of recombination lines is defined by electron impact broadening, in active regions with field strengths 25 G the Zeeman broadening will shift this boundary to higher frequencies. The frequency region most favourable for observations is derived and the corresponding Doppler, electron impact and Zeeman broadening are discussed. The strengths of the recombination lines obtained in earlier calculations is reduced when one considers besides the Doppler broadening the electron impact and Zeeman broadening also. The frequency region favourable for observations is compared with the atmospheric transparency of the microwave region; it is found that observations require at least high altitude stations or space-based platforms. Details of using the Zeeman broadening of high n recombination lines for mapping (coronal) magnetic fields are given. 相似文献
6.
7.
8.
CPT Clifford W. Greve 《Journal of Geodesy》1972,46(1):31-45
This paper discusses theory and results of an attempt to use non-linear programming methods to arrive at an optimal, in the
sense of least cost, solution to the design of a survey system to meet specified accuracy. In other words, the method determines
the combination of various types of observations which will yield the required accuracy of control points for a minimum cost.
The theoretical background of the procedure is discussed, and methods of extension to photo-grammetry and other sciences are
presented. Much of the paper is concerned with discussing results of numerical solutions for the optimal design of several
small, but typical, mapping problems.
It is believed that this research is original with the author, as extensive literature searches and correspondence has produced
no knowledge of prior research into this application of nonlinear programming. The method at its current state of development
appears to be capable of yielding significant improvements to the present concepts of survey network design. 相似文献
9.
On November 27, 1974, a map of the Moon was obtained at 6 cm wavelength with the 100-m-telescope in Effelsberg. The high angular and favourable temperature resolution allowed an interpretation of the observed brightness distribution. The dominant feature of the brightness distribution is the centre-to-limb variation, particularly noticeable in the direction of the poles. The exponent of the commonly adopted cos
()-law, describing the temperature variation across the lunar disk, is determined as 0.4. The North-South variation of the lunar surface temperature is estimated to be 30%; the depth of penetration (L
e) of electromagnetic waves of 6 cm wavelength is found to beL
e 17 m. 相似文献
10.