全文获取类型
收费全文 | 810篇 |
免费 | 44篇 |
国内免费 | 8篇 |
专业分类
测绘学 | 29篇 |
大气科学 | 30篇 |
地球物理 | 211篇 |
地质学 | 297篇 |
海洋学 | 109篇 |
天文学 | 141篇 |
综合类 | 5篇 |
自然地理 | 40篇 |
出版年
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 18篇 |
2020年 | 19篇 |
2019年 | 21篇 |
2018年 | 27篇 |
2017年 | 37篇 |
2016年 | 37篇 |
2015年 | 38篇 |
2014年 | 39篇 |
2013年 | 50篇 |
2012年 | 43篇 |
2011年 | 61篇 |
2010年 | 40篇 |
2009年 | 73篇 |
2008年 | 63篇 |
2007年 | 40篇 |
2006年 | 27篇 |
2005年 | 21篇 |
2004年 | 24篇 |
2003年 | 28篇 |
2002年 | 16篇 |
2001年 | 14篇 |
2000年 | 19篇 |
1999年 | 14篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1970年 | 2篇 |
1961年 | 1篇 |
1952年 | 4篇 |
1950年 | 1篇 |
排序方式: 共有862条查询结果,搜索用时 0 毫秒
861.
Camila Rodrigues Costa Cynthia Fernandes Pinto da Luz Ingrid Horák-Terra Plínio Barbosa de Camargo Uidemar Morais Barral Carlos Victor Mendonça-Filho Thamyres Sabrina Gonçalves Alexandre Christófaro Silva 《第四纪科学杂志》2023,38(1):61-75
The Cerrado biome is the second largest in Brazil, but the evolution of the Cerrado during the late Quaternary is not yet fully known. This study identifies paleoenvironmental changes during the last 23 000 years, based on a tropical mountain peatland record, in the Serra do Espinhaço Meridional in central-eastern Brazil. A multi-proxy approach was used that involved palynological analysis, stable isotopes (δ13C, δ15N), geochemistry, radiocarbon dating and multivariate statistics derived from a peatland core from Rio Preto (Minas Gerais state). The study reveals a very humid and cold climate during the late Pleistocene, with an increase in temperature and decrease in humidity at the Pleistocene–Holocene transition. During this period there was strong instability in the landscape (episodes of erosion). At the beginning of the Holocene there was a reduction in humidity with greater landscape stability. The current sub-humid climatic conditions seem to have been established in the mid-/late Holocene, with periods of landscape instability. Our findings agree with other Cerrado records that contradict previously established hypotheses, such as the Amazonian Refuge and the Pleistocene Arc. 相似文献
862.
M. Fernandes M. Oliva G. Vieira D. Palacios J. M. Fernndez-Fernndez J. Garcia-oteyza I. Schimmelpfennig Aster Team D. Antoniades 《第四纪科学杂志》2022,37(1):42-58
The Upper Garonne Basin included the largest glacial system in the Pyrenees during the last glacial cycle. Within the long-term glacial retreat during Termination-1 (T-1), glacier fluctuations left geomorphic evidence in the area. However, the chronology of T-1 glacial oscillations on the northern slopes of the Central Pyrenees is still poorly constrained. Here, we introduce new geomorphological observations and a 12-sample dataset of 10Be cosmic-ray exposure ages from the Ruda Valley. This U-shaped valley, surrounded by peaks exceeding 2800 m a.s.l., includes a sequence of moraines and polished surfaces that enabled a reconstruction of the chronology of the last deglaciation. Following the maximum ice extent, warmer conditions prevailing at ~15–14 ka, during the Bølling–Allerød (B–A) Interstadial, favoured glacial retreat in the Ruda Valley. Within the B–A, glaciers experienced two phases of advance/stillstand with moraine formation at 13.5 and 13.0 ka. During the early Younger Dryas (YD), glacial retreat exposed the highest surfaces of the Saboredo Cirque (~2300–2350 m) at 12.7 ka. Small glaciers persisted only inside the highest cirques (~2470 m), such as in Sendrosa Cirque, with moraines stabilising at 12.6 ka. The results of this work present the most complete chronology for Pyrenean glacial oscillations from the B–A to the YD. 相似文献