全文获取类型
| 收费全文 | 5402篇 |
| 免费 | 790篇 |
| 国内免费 | 789篇 |
专业分类
| 测绘学 | 35篇 |
| 大气科学 | 282篇 |
| 地球物理 | 286篇 |
| 地质学 | 3111篇 |
| 海洋学 | 221篇 |
| 天文学 | 2572篇 |
| 综合类 | 198篇 |
| 自然地理 | 276篇 |
出版年
| 2024年 | 16篇 |
| 2023年 | 40篇 |
| 2022年 | 109篇 |
| 2021年 | 121篇 |
| 2020年 | 113篇 |
| 2019年 | 144篇 |
| 2018年 | 113篇 |
| 2017年 | 135篇 |
| 2016年 | 134篇 |
| 2015年 | 163篇 |
| 2014年 | 212篇 |
| 2013年 | 216篇 |
| 2012年 | 234篇 |
| 2011年 | 276篇 |
| 2010年 | 236篇 |
| 2009年 | 462篇 |
| 2008年 | 373篇 |
| 2007年 | 456篇 |
| 2006年 | 451篇 |
| 2005年 | 417篇 |
| 2004年 | 384篇 |
| 2003年 | 372篇 |
| 2002年 | 300篇 |
| 2001年 | 254篇 |
| 2000年 | 230篇 |
| 1999年 | 206篇 |
| 1998年 | 205篇 |
| 1997年 | 100篇 |
| 1996年 | 71篇 |
| 1995年 | 87篇 |
| 1994年 | 66篇 |
| 1993年 | 57篇 |
| 1992年 | 61篇 |
| 1991年 | 32篇 |
| 1990年 | 31篇 |
| 1989年 | 43篇 |
| 1988年 | 20篇 |
| 1987年 | 13篇 |
| 1986年 | 10篇 |
| 1985年 | 3篇 |
| 1984年 | 5篇 |
| 1983年 | 1篇 |
| 1982年 | 1篇 |
| 1981年 | 1篇 |
| 1980年 | 4篇 |
| 1978年 | 1篇 |
| 1977年 | 1篇 |
| 1954年 | 1篇 |
排序方式： 共有6981条查询结果，搜索用时 265 毫秒
1.
Hydrological trends and the evolution of catchment research in the Alptal valley,central Switzerland
Manfred Stähli Jan Seibert James W. Kirchner Jana von Freyberg Ilja van Meerveld 《水文研究》2021,35(4):e14113
When the observation of small headwater catchments in the pre-Alpine Alptal valley (central Switzerland) started in the late 1960s, the researchers were mainly interested in questions related to floods and forest management. Investigations of geomorphological processes in the steep torrent channels followed in the 1980s, along with detailed observations of biogeochemical and ecohydrological processes in individual forest stands. More recently, research in the Alptal has addressed the impacts of climate change on water supply and runoff generation. In this article, we describe, for the first time, the evolution of catchment research at Alptal, and present new analyses of long-term trends and short-term hydrologic behaviour. Hydrometeorological time series from the past 50 years show substantial interannual variability, but only minimal long-term trends, except for the ~2°C increase in mean annual air temperature over the 50-year period, and a corresponding shift towards earlier snowmelt. Similar to previous studies in larger Alpine catchments, the decadal variations in mean annual runoff in Alptal's small research catchments reflect the long-term variability in annual precipitation. In the Alptal valley, the most evident hydrological trends were observed in late spring and are related to the substantial change in the duration of the snow cover. Streamflow and water quality are highly variable within and between hydrological events, suggesting rapid shifts in flow pathways and mixing, as well as changing connectivity of runoff-generating areas. This overview illustrates how catchment research in the Alptal has evolved in response to changing societal concerns and emerging scientific questions. 相似文献
2.
3.
4.
5.
6.
J. Raitala 《Earth, Moon, and Planets》1996,74(3):191-214
The intrablock deformation of Meshkenet Tessera on Venus is mostly due to responses of the uppermost surface bedrock to tensional stresses. It is found that complex deformation structures within the highland blocks resemble those of formed in chocolate tablet boudinaging which has taken place after original parallel faulting and bar-like crustal block formation. The high-angle tessera structures with varying cross-cutting relations define styles and locations of multiphase deformation most evidently related to local relaxation of tessera topography. Series of progressive or superposed fracturing events with alternating fault directions took place at high angles during this relaxational deformation. Compressional ridges often surround these tesserae. 相似文献
7.
8.
9.
10.