全文获取类型
| 收费全文 | 12632篇 |
| 免费 | 2101篇 |
| 国内免费 | 2484篇 |
专业分类
| 测绘学 | 1277篇 |
| 大气科学 | 472篇 |
| 地球物理 | 3209篇 |
| 地质学 | 5775篇 |
| 海洋学 | 1259篇 |
| 天文学 | 3972篇 |
| 综合类 | 589篇 |
| 自然地理 | 664篇 |
出版年
| 2024年 | 21篇 |
| 2023年 | 103篇 |
| 2022年 | 327篇 |
| 2021年 | 427篇 |
| 2020年 | 437篇 |
| 2019年 | 500篇 |
| 2018年 | 353篇 |
| 2017年 | 416篇 |
| 2016年 | 419篇 |
| 2015年 | 490篇 |
| 2014年 | 668篇 |
| 2013年 | 628篇 |
| 2012年 | 610篇 |
| 2011年 | 665篇 |
| 2010年 | 563篇 |
| 2009年 | 922篇 |
| 2008年 | 873篇 |
| 2007年 | 991篇 |
| 2006年 | 988篇 |
| 2005年 | 871篇 |
| 2004年 | 888篇 |
| 2003年 | 786篇 |
| 2002年 | 622篇 |
| 2001年 | 542篇 |
| 2000年 | 546篇 |
| 1999年 | 521篇 |
| 1998年 | 550篇 |
| 1997年 | 249篇 |
| 1996年 | 248篇 |
| 1995年 | 201篇 |
| 1994年 | 163篇 |
| 1993年 | 126篇 |
| 1992年 | 120篇 |
| 1991年 | 73篇 |
| 1990年 | 78篇 |
| 1989年 | 51篇 |
| 1988年 | 31篇 |
| 1987年 | 31篇 |
| 1986年 | 20篇 |
| 1985年 | 13篇 |
| 1984年 | 12篇 |
| 1983年 | 6篇 |
| 1982年 | 6篇 |
| 1981年 | 5篇 |
| 1980年 | 4篇 |
| 1979年 | 8篇 |
| 1978年 | 10篇 |
| 1977年 | 12篇 |
| 1973年 | 5篇 |
| 1954年 | 13篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
31.
32.
The finite‐element formulation and integration algorithms developed in Part I are used to analyse a number of practical problems involving unsaturated and saturated soils. The formulation and algorithms perform well for all the cases analysed, with the robustness of the latter being largely insensitive to user‐defined parameters such as the number of coarse time steps and error control tolerances. The efficiency of the algorithms, as measured by the CPU time consumed, does not depend on the number of coarse time steps, but may be influenced by the error control tolerances. Based on the analyses presented here, typical values for the error control tolerances are suggested. It is also shown that the constitutive modelling framework presented in Part I can, by adjusting one constitutive equation and one or two material parameters, be used to simulate soils that expand or collapse upon wetting. Treating the suction as a strain variable instead of a stress variable proves to be an efficient and robust way of solving suction‐dependent plastic yielding. Moreover, the concept of the constitutive stress is a particularly convenient way of handling the transition between saturation and unsaturation. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
33.
34.
N. Ivanova K. Belczynski J. M. Fregeau F. A. Rasio 《Monthly notices of the Royal Astronomical Society》2005,358(2):572-584
We study the evolution of binary stars in globular clusters using a new Monte Carlo approach combining a population synthesis code ( startrack ) and a simple treatment of dynamical interactions in the dense cluster core using a new tool for computing three- and four-body interactions ( fewbody ). We find that the combination of stellar evolution and dynamical interactions (binary–single and binary–binary) leads to a rapid depletion of the binary population in the cluster core. The maximum binary fraction today in the core of a typical dense cluster such as 47 Tuc, assuming an initial binary fraction of 100 per cent, is only ∼ 5–10 per cent. We show that this is in good agreement with recent Hubble Space Telescope observations of close binaries in the core of 47 Tuc, provided that a realistic distribution of binary periods is used to interpret the results. Our findings also have important consequences for the dynamical modelling of globular clusters, suggesting that 'realistic models' should incorporate much larger initial binary fractions than has usually been the case in the past. 相似文献
35.
36.
37.
38.
39.
40.