全文获取类型
收费全文 | 395篇 |
免费 | 9篇 |
国内免费 | 7篇 |
专业分类
测绘学 | 6篇 |
大气科学 | 12篇 |
地球物理 | 151篇 |
地质学 | 119篇 |
海洋学 | 24篇 |
天文学 | 59篇 |
综合类 | 3篇 |
自然地理 | 37篇 |
出版年
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 7篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 12篇 |
2012年 | 11篇 |
2011年 | 11篇 |
2010年 | 14篇 |
2009年 | 12篇 |
2008年 | 13篇 |
2007年 | 22篇 |
2006年 | 10篇 |
2005年 | 22篇 |
2004年 | 7篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 10篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 2篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1973年 | 5篇 |
1969年 | 1篇 |
1968年 | 3篇 |
排序方式: 共有411条查询结果,搜索用时 0 毫秒
91.
Hg and As Minerals in Fluid Inclusions from the Williams Mine,Hemlo,and Their Genetic Implications 总被引:1,自引:0,他引:1
卢焕章 《中国地球化学学报》2002,21(1):1-18
The Hemlo mineralization is enigmatic compared to general Archean lode gold deposits based on the fact that is characterized by an exotic mineralogy containing elements such as As,Hg,Sb,Ba,V and Mo.The genetic concepts range from syngenetc to epigenetic types of mineralization.This reconnaissance study was designed to examine the relationshp of Hg-As minerals with respect of fluid inclusions in the Williams mine(formerly known as the Page Williams mine)covering the A and C ore zones. 相似文献
92.
93.
94.
95.
Natural Hazards - A large number of studies have identified significant physical, biological and health effects associated with changes in Solar and Geomagnetic Activity (S-GMA). Variations in... 相似文献
96.
Anna E. Klene Frederick E. Nelson John Nevins Don Rogers Nikolay I. Shiklomanov 《Geomorphology》2002,47(2-4)
Permafrost and periglacial geomorphology are absent from the science curriculum in most secondary schools in the United States. This is an unfortunate situation given the recent increases in development and environmental concerns in northern latitudes and high-mountain areas, and the interesting examples of basic scientific principles found in the history of research on periglacial geomorphology and permafrost. In 1997 and 1998, a University of Delaware research group studying permafrost and periglacial geomorphology in northern Alaska participated in the National Science Foundation's (NSF) Teachers Experiencing the Antarctic and Arctic (TEA) Program. In each of these years, a high school teacher and a student traveled as part of the research team to the North Slope of Alaska. They learned about the landscape, collected active-layer thickness and temperature measurements, and assisted in data analysis. Results from studies of active-layer thickness variability and ground temperature contributed to a series of long-term observations and international research on the impacts of global climate change. Since their expeditions, the teachers have shared their experiences with their classrooms and communities in several ways, including public lectures and the Internet. Classroom activities are available to the public through the TEA web site (http://tea.rice.edu). This experience may heighten public awareness of permafrost and contribute to it becoming a useful part of the secondary curriculum. 相似文献
97.
98.
Stefanie Wachter Chryssa Kouveliotou Sandeep Patel Don Figer Peter Woods 《Astrophysics and Space Science》2007,308(1-4):67-71
Both Anomalous X-ray Pulsars (AXPs) and Soft Gamma Repeaters (SGRs) are thought to be manifestations of magnetars. However, the specific physical characteristics that differentiate the two classes of objects remain unclear. There is some evidence that the progenitors of these sources and/or the environment in which they form might influence the type of phenomena the resulting magnetar displays. Several of the AXPs appear to be associated with supernova remnants, while embedded clusters of massive stars have been found in the immediate vicinity of some SGRs. Since both AXPs and SGRs are distributed close to the Galactic plane, high extinction makes studies in the optical difficult. We present early results from our Spitzer program aimed at probing the environmental factors that might contribute to the difference in the observed characteristics between AXPs and SGRs. 相似文献
99.
100.