全文获取类型
收费全文 | 589篇 |
免费 | 7篇 |
国内免费 | 25篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 1篇 |
地球物理 | 11篇 |
地质学 | 41篇 |
海洋学 | 34篇 |
天文学 | 508篇 |
综合类 | 18篇 |
自然地理 | 6篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 10篇 |
2013年 | 17篇 |
2012年 | 9篇 |
2011年 | 8篇 |
2010年 | 14篇 |
2009年 | 39篇 |
2008年 | 47篇 |
2007年 | 42篇 |
2006年 | 45篇 |
2005年 | 85篇 |
2004年 | 40篇 |
2003年 | 41篇 |
2002年 | 38篇 |
2001年 | 25篇 |
2000年 | 34篇 |
1999年 | 30篇 |
1998年 | 40篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
排序方式: 共有621条查询结果,搜索用时 15 毫秒
1.
2.
3.
Travis S. Metcalfe 《Astrophysics and Space Science》2003,284(1):141-151
A flood of reliable seismic data will soon arrive. The migration to largertelescopes on the ground may free up 4-m class instruments for multi-sitecampaigns, and several forthcoming satellite missions promise to yieldnearly uninterrupted long-term coverage of many pulsating stars. We willthen face the challenge of determining the fundamental properties of thesestars from the data, by trying to match them with the output of ourcomputer models. The traditional approach to this task is to make informedguesses for each of the model parameters, and then adjust them iterativelyuntil an adequate match is found. The trouble is: how do we know that oursolution is unique, or that some other combination of parameters will notdo even better? Computers are now sufficiently powerful and inexpensivethat we can produce large grids of models and simply compare all ofthem to the observations. The question then becomes: what range ofparameters do we want to consider, and how many models do we want tocalculate? This can minimize the subjective nature of the process, but itmay not be the most efficient approach and it may give us a false sense ofsecurity that the final result is correct, when it is really justoptimal. I discuss these issues in the context of recent advances inthe asteroseismological analysis of white dwarf stars. 相似文献
4.
5.
6.
P. Lorén-Aguilar J. Guerrero J. Isern J. A. Lobo E. García-Berro 《Monthly notices of the Royal Astronomical Society》2005,356(2):627-636
We compute the emission of gravitational radiation from the merging of a close white dwarf binary system. This is done for a wide range of masses and compositions of the white dwarfs, ranging from mergers involving two He white dwarfs, through mergers in which two CO white dwarfs coalesce, to mergers in which a massive ONe white dwarf is involved. In doing so we follow the evolution of the binary system using a smoothed particle hydrodynamics code. Even though the coalescence process of the white dwarfs involves considerable masses, moving at relatively high velocities with a high degree of asymmetry we find that the signature of the merger is not very strong. In fact, the most prominent feature of the coalescence is that in a relatively small time-scale (of the order of the period of the last stable orbit, typically a few minutes) the sources stop emitting gravitational waves. We also discuss the possible implications of our calculations for the detection of the coalescence within the framework of future space-borne interferometers like LISA. 相似文献
7.
8.
Late Cretaceous-Paleogene Palynostratigraphy from the Arkhara-Boguchan Brown Coal Mine of Zeya-Bureya Depression, Russia 总被引:1,自引:1,他引:0
Tatyana V. Kezina 《东北亚地学研究》2003,(2)
1IntroductionThe Arkhara-Boguchan brown coal mine is lo-cated in the western Arkhara depression,southeast-ern part of the Zea-Bureya Basin (Fig.1). Late Creta-ceous-Paleogene coal-bearing strata are well out-cropped at the Arkhara-Boguchan quarry. It contains four coal-bearing beds (in descending order): “Ve-likan”, “Promezhutochny”,“Dvoinoy”and “Nyzhny”, and composed of three sedimentary cycles (Fig.2). The lower cycle can be divided into two sub-cycles:the lowest sub-cycle is … 相似文献
9.
10.