全文获取类型
| 收费全文 | 255977篇 |
| 免费 | 5326篇 |
| 国内免费 | 3318篇 |
专业分类
| 测绘学 | 7010篇 |
| 大气科学 | 19255篇 |
| 地球物理 | 53536篇 |
| 地质学 | 89000篇 |
| 海洋学 | 21712篇 |
| 天文学 | 55108篇 |
| 综合类 | 1019篇 |
| 自然地理 | 17981篇 |
出版年
| 2021年 | 2193篇 |
| 2020年 | 2604篇 |
| 2019年 | 2843篇 |
| 2018年 | 3797篇 |
| 2017年 | 3386篇 |
| 2016年 | 5901篇 |
| 2015年 | 4237篇 |
| 2014年 | 6958篇 |
| 2013年 | 14288篇 |
| 2012年 | 6653篇 |
| 2011年 | 8167篇 |
| 2010年 | 7162篇 |
| 2009年 | 9847篇 |
| 2008年 | 8576篇 |
| 2007年 | 8078篇 |
| 2006年 | 9689篇 |
| 2005年 | 7772篇 |
| 2004年 | 7699篇 |
| 2003年 | 7202篇 |
| 2002年 | 6778篇 |
| 2001年 | 5949篇 |
| 2000年 | 5599篇 |
| 1999年 | 4821篇 |
| 1998年 | 4858篇 |
| 1997年 | 4646篇 |
| 1996年 | 4227篇 |
| 1995年 | 4333篇 |
| 1994年 | 4008篇 |
| 1993年 | 3752篇 |
| 1992年 | 3509篇 |
| 1991年 | 3532篇 |
| 1990年 | 3631篇 |
| 1989年 | 3339篇 |
| 1988年 | 3172篇 |
| 1987年 | 3723篇 |
| 1986年 | 3262篇 |
| 1985年 | 4130篇 |
| 1984年 | 4645篇 |
| 1983年 | 4313篇 |
| 1982年 | 4223篇 |
| 1981年 | 3860篇 |
| 1980年 | 3598篇 |
| 1979年 | 3435篇 |
| 1978年 | 3447篇 |
| 1977年 | 3220篇 |
| 1976年 | 2968篇 |
| 1975年 | 2908篇 |
| 1974年 | 2865篇 |
| 1973年 | 3066篇 |
| 1972年 | 1995篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
991.
High‐resolution reconstruction of a coastal barrier system: impact of Holocene sea‐level change 
下载免费PDF全文
下载免费PDF全文 Mikkel Fruergaard Thorbjørn J. Andersen Lars H. Nielsen Peter N. Johannessen Troels Aagaard Morten Pejrup 《Sedimentology》2015,62(3):928-969
This study presents a detailed reconstruction of the sedimentary effects of Holocene sea‐level rise on a modern coastal barrier system. Increasing concern over the evolution of coastal barrier systems due to future accelerated rates of sea‐level rise calls for a better understanding of coastal barrier response to sea‐level changes. The complex evolution and sequence stratigraphic framework of the investigated coastal barrier system is reconstructed using facies analysis, high‐resolution optically stimulated luminescence and radiocarbon dating. During the formation of the coastal barrier system starting 8 to 7 ka rapid relative sea‐level rise outpaced sediment accumulation. Not before rates of relative sea‐level rise had decreased to ca 2 mm yr?1 did sediment accumulation outpace sea‐level rise. From ca 5·5 ka, rates of regionally averaged sediment accumulation increased to 4·3 mm yr?1 and the back‐barrier basin was filled in. This increase in sediment accumulation resulted from retreat of the barrier island and probably also due to formation of a tidal inlet close to the study area. Continued transgression and shoreface retreat created a distinct hiatus and wave ravinement surface in the seaward part of the coastal barrier system before the barrier shoreline stabilized between 5·0 ka and 4·5 ka. Back‐barrier shoreline erosion due to sediment starvation in the back‐barrier basin was pronounced from 4·5 to 2·5 ka but, in the last 2·5 kyr, barrier sedimentation has kept up with and outpaced sea‐level. In the last 0·4 kyr the coastal barrier system has been prograding episodically. Sediment accumulation shows considerable variation, with periods of rapid sediment deposition and periods of non‐deposition or erosion resulting in a highly punctuated sediment record. The study demonstrates how core‐based facies interpretations supported by a high‐resolution chronology and a well‐documented sea‐level history allow identification of depositional environments, erosion surfaces and hiatuses within a very homogeneous stratigraphy, and allow a detailed temporal reconstruction of a coastal barrier system in relation to sea‐level rise and sediment supply. 相似文献
992.
993.
Journal of Earth System Science - Based on the daily maximum air temperature data from 176 stations in India from 1969 to 2013, the climatological distribution of the number of days with high... 相似文献
994.
Discussed is the hydrodynamic model of iceberg drift. Presented are the examples ofits use in operational practice for predicting iceberg drift in the Kara Sea and for enhancing ice monitoring in the Barents Sea. 相似文献
995.
996.
997.
998.
999.
1000.