全文获取类型
收费全文 | 148篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 9篇 |
地球物理 | 34篇 |
地质学 | 59篇 |
海洋学 | 8篇 |
天文学 | 22篇 |
自然地理 | 22篇 |
出版年
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 3篇 |
2010年 | 8篇 |
2009年 | 15篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有155条查询结果,搜索用时 15 毫秒
51.
Fiona A. Harrison Finn E. Christensen William Craig Charles Hailey Wayne Baumgartner C. M. H. Chen James Chonko W. Rick Cook Jason Koglin Kristin-Kruse Madsen Michael Pivavoroff Steven Boggs David Smith 《Experimental Astronomy》2005,20(1-3):131-137
Hard X-ray/soft gamma-ray astrophysics is on the verge of a major advance with the practical realization of technologies capable of efficiently focusing X-rays above 10 keV. Hard X-ray focusing telescopes can achieve orders of magnitude improvements in sensitivity compared to the instruments based on coded apertures and collimated detectors that have traditionally been employed in this energy band. Compact focal planes enable high-performance detectors with good spectral resolution to be employed in efficient, low-background configurations. We have developed multilayer coated grazing incidence optics and solid state Cadmium Zinc Telluride focal plane systems for the High Energy Focusing Telescope (HEFT) balloon-borne experiment, and for the Nuclear Spectroscopic Telescope Array (NuSTAR) Small Explorer satellite. In this paper we describe the technologies, telescope designs, and performance of both experiments. 相似文献
52.
53.
54.
55.
Fiona Simpson 《GeoJournal》2000,50(2-3):127-131
Ethnic minorities are facing increasing problems of social exclusion in Central and Eastern Europe. The complex nature of
the transition from socialism means that the institutional framework to support them is still being established. Whilst non-governmental
organisations (NGOs) have a crucial role to play in promoting a more inclusive society, through improving access to local
democratic structures for otherwise excluded groups and acting as fora for improved community participation throughout the
region, their development remains fraught with problems. Examination of the experiences of one such organisation, ETNO Agentura
based in northern Slovakia, provides an insight into the problems and opportunities arising as community representatives work
together to provide social support for ethnic minorities. The paper outlines key issues arising from the case of ETNO Agentura,
including difficulty in gaining access to supporting finance and securing long term financial viability, the lack of institutional
capacity of local authorities to become receptive to their views, and implicit socio-cultural barriers to ethnic minority
representation in community participation processes. Developing a fuller understanding of these problems and the measures
required to overcome them is a central part of establishing a more effective role for NGOs within post socialist societies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
56.
New articulated specimens of the British Ordovician cystoid first mentioned under the name ‘Hemicosmites rugatus Forbes’ in 1848 allow its morphology and systematic affinities to be established for the first time. Despite being based on isolated plates, ‘H. rugatus Forbes’ has been reported from England and Wales, Belgium, France, Spain and Thailand, and has been attributed to four genera. It is characterized by a heteromorphic, circular stem, a theca with four basal, six infra‐lateral and eight lateral plates, all with sharp‐crested ridges running to plate angles, multiple arms in each ambulacrum and an extensive tegmen. These characters indicate it belongs in the family Caryocrinitidae and genus Caryocrinites. Caryocrinites rugatus had arms with lateral brachioles that folded in against the main arm axis, as in the type species C. ornatus Say. It is the first Ordovician species known to possess this character. Isolated plates show sorting and a few may represent other species of Caryocrinites s.l. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
57.
The aim of this study was to determine the extent Nephrops consumes plastics in the Clyde Sea and if this intake occurs through their diet. Plastic contamination was found to be high in Nephrops, 83% of the animals sampled contained plastics (predominately filaments) in their stomachs. Tightly tangled balls of plastic strands were found in 62% of the animals studied but were least prevalent in animals which had recently moulted. No significant difference in plastic load was observed between males and females. Raman spectroscopy indicated that some of the microfilaments identified from gut contents could be sourced to fishing waste. Nephrops fed fish seeded with strands of polypropylene rope were found to ingest but not to excrete the strands. The fishery for Norway lobster, Nephrops norvegicus, is the most valuable in Scotland and the high prevalence of plastics in Nephrops may have implications for the health of the stock. 相似文献
58.
59.
60.