全文获取类型
| 收费全文 | 1486篇 |
| 免费 | 74篇 |
| 国内免费 | 4篇 |
专业分类
| 测绘学 | 19篇 |
| 大气科学 | 99篇 |
| 地球物理 | 366篇 |
| 地质学 | 712篇 |
| 海洋学 | 123篇 |
| 天文学 | 177篇 |
| 综合类 | 5篇 |
| 自然地理 | 63篇 |
出版年
| 2023年 | 5篇 |
| 2022年 | 18篇 |
| 2021年 | 25篇 |
| 2020年 | 24篇 |
| 2019年 | 34篇 |
| 2018年 | 54篇 |
| 2017年 | 62篇 |
| 2016年 | 61篇 |
| 2015年 | 55篇 |
| 2014年 | 76篇 |
| 2013年 | 116篇 |
| 2012年 | 55篇 |
| 2011年 | 118篇 |
| 2010年 | 93篇 |
| 2009年 | 103篇 |
| 2008年 | 83篇 |
| 2007年 | 53篇 |
| 2006年 | 62篇 |
| 2005年 | 56篇 |
| 2004年 | 52篇 |
| 2003年 | 41篇 |
| 2002年 | 39篇 |
| 2001年 | 23篇 |
| 2000年 | 23篇 |
| 1999年 | 15篇 |
| 1998年 | 13篇 |
| 1997年 | 15篇 |
| 1996年 | 13篇 |
| 1995年 | 10篇 |
| 1994年 | 19篇 |
| 1993年 | 10篇 |
| 1992年 | 15篇 |
| 1991年 | 14篇 |
| 1990年 | 6篇 |
| 1989年 | 14篇 |
| 1988年 | 6篇 |
| 1987年 | 8篇 |
| 1986年 | 7篇 |
| 1985年 | 4篇 |
| 1984年 | 4篇 |
| 1983年 | 9篇 |
| 1982年 | 5篇 |
| 1981年 | 4篇 |
| 1980年 | 6篇 |
| 1979年 | 6篇 |
| 1977年 | 5篇 |
| 1975年 | 6篇 |
| 1974年 | 3篇 |
| 1973年 | 4篇 |
| 1962年 | 2篇 |
排序方式： 共有1564条查询结果，搜索用时 15 毫秒
991.
Landslide susceptibility mapping (LSM) is important for catastrophe management in the mountainous regions. They focus on generating susceptibility maps beginning from landslide inventories and considering the main predisposing parameters. The aim of this study was to assess the susceptibility of the occurrence of debris flows in the Zêzere River basin and its surrounding area using logistic regression (LR) and frequency ratio (FR) models. To achieve this, a landslide inventory map was created using historical information, satellite imagery, and extensive field works. One hundred landslides were mapped, of which 75% were randomly selected as training data, while the remaining 25% were used for validating the models. The landslide influence factors considered for this study were lithology, elevation, slope gradient, slope aspect, plan curvature, profile curvature, normalized difference vegetation index (NDVI), distance to roads, topographic wetness index (TWI), and stream power index (SPI). The relationships between landslide occurrence and these factors were established, and the results were then evaluated and validated. Validation results show that both methods give acceptable results [the area under curve (AUC) of success rates is 83.71 and 76.38 for LR and FR, respectively]. Furthermore, the AUC results for prediction accuracy revealed that LR model has the highest predictive performance (AUC of predicted rate?=?80.26). Hence, it is concluded that the two models showed reasonably good accuracy in predicting the landslide susceptibility in the study area. These two models have the potential to aid planners in development and land-use planning and to offer tools for hazard mitigation measures. 相似文献
992.
Konopásek Jiří Janoušek Vojtěch Oyhantçabal Pedro Sláma Jiří Ulrich Stanislav 《International Journal of Earth Sciences》2018,107(5):1859-1894
International Journal of Earth Sciences - Early Neoproterozoic metaigneous rocks occur in the central part of the Kaoko–Dom Feliciano–Gariep orogenic system along the coasts of the... 相似文献
993.
994.
995.
996.
997.
On our way toward the characterization of smaller and more temperate planets, missions dedicated to the spectroscopic observation of exoplanets will teach us about the wide diversity of classes of planetary atmospheres, many of them probably having no equivalent in the Solar System. But what kind of atmospheres can we expect? To start answering this question, many theoretical studies have tried to understand and model the various processes controlling the formation and evolution of planetary atmospheres, with some success in the Solar System. Here, we shortly review these processes and we try to give an idea of the various type of atmospheres that these processes can create. As will be made clear, current atmosphere evolution models have many shortcomings yet, and need heavy calibrations. With that in mind, we will thus discuss how observations with a mission similar to EChO would help us unravel the link between a planet’s environment and its atmosphere. 相似文献
998.
999.
1000.
The SARAL/AltiKa project is based on a single Ka band altimeter (35.75 GHz), which is the first oceanography altimeter to operate at such a high frequency. Ka band offers reduced radar footprint in comparison to traditional Ku band altimeters and negligible ionospheric effects. In this paper we present and evaluate benefits of AltiKa altimeter applied in the study of lakes in Andean chain in South America. Water levels time series obtained with Envisat/RA-2 and SARAL/AltiKa altimeters over 17 lakes of various sizes are calculated and compared to in situ observations. SARAL/AltiKa measurements tend to be extremely well correlated with in situ measurements and offer significant improvements compared to the Envisat mission. 相似文献