全文获取类型
收费全文 | 629篇 |
免费 | 28篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 12篇 |
大气科学 | 27篇 |
地球物理 | 211篇 |
地质学 | 220篇 |
海洋学 | 42篇 |
天文学 | 109篇 |
综合类 | 2篇 |
自然地理 | 39篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 14篇 |
2019年 | 11篇 |
2018年 | 21篇 |
2017年 | 18篇 |
2016年 | 45篇 |
2015年 | 27篇 |
2014年 | 27篇 |
2013年 | 35篇 |
2012年 | 31篇 |
2011年 | 46篇 |
2010年 | 28篇 |
2009年 | 35篇 |
2008年 | 36篇 |
2007年 | 14篇 |
2006年 | 24篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1987年 | 5篇 |
1979年 | 4篇 |
1976年 | 3篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1954年 | 2篇 |
1952年 | 5篇 |
1951年 | 4篇 |
1950年 | 3篇 |
1949年 | 2篇 |
1948年 | 8篇 |
1941年 | 3篇 |
1940年 | 3篇 |
1939年 | 6篇 |
排序方式: 共有662条查询结果,搜索用时 0 毫秒
661.
Mario Octavio Cotilla Rodríguez Diego Córdoba Barba 《Russian Geology and Geophysics》2010,51(11):1227-1246
On August 20, 1852, an earthquake caused widespread destruction in the city of Santiago de Cuba and its surroundings. A comprehensive search for contemporary documentation was made. The information gathered was used for a detailed analysis of the damage from and characteristics of the earthquakes. Intensities were evaluated at 45 localities, and an isoseismal scheme has been drawn. Maximum intensity reached 8 degrees (MSK), and 6.4 was the estimated magnitude. Damage to the city of Santiago de Cuba has been studied in detail. The low quality of construction aggravated the damage. The total number of casualties was two dead and approximately 200 injured. The shock was felt within 80,000 km2. The epicenter was determined as 19.75º N, 75.32º W, h = 30 km. This study shows that contemporary Cuban documents must be studied with care in their historical and cultural background to avoid overestimating earthquake intensities. 相似文献
662.
Julien Nikiema Mario Schirmer Walter Gläßer Ronald Krieg 《Environmental Earth Sciences》2010,61(1):11-26
About 24 samples from hand-dug wells and boreholes were used to characterize concentrations of the main inorganic ions in
a laterite environment under semi-arid climatic conditions in Tikaré, northern Burkina Faso. It was found that the most represented
groundwater anion in groundwater was HCO3
− with average levels of 49.1 mg/L in the dry season and 33.5 mg/L in the rainy season. The most represented cation was Ca2+ with mean concentrations of 13.7 and 9.5 mg/L, respectively. The main processes, which influence the concentrations of these
ions, are evaporation (dry season), local enrichment of recharge water in some elements, ion exchange and fixation by clay
minerals (in case of K+). The best correlations were found between Ca2+ and Mg2+ (r = 0.95), Cl− and Na+ (r = 0.95), HCO3
− and Mg2+ (r = 0.89), HCO3
− and Ca2+ (r = 0.89), and between HCO3
− and Na+ (r = 0.80). In general, the quality of the groundwater from the different wells sampled for this study was good enough to serve
as drinking water. However, there were situations where the quality of water was polluted because of anthropogenic contaminants
(mainly NO3
−, K+, Cl−) from septic tanks and manure pits located in the vicinity of some sampled wells. In addition, application of fertilizers
also represents a potential anthropogenic contamination source with regard to SO4
2−, Ca2+, K+, Na+, and Mg2+. Considering the high concentrations of SO4
2−, Mg2+, Na+ and Ca2+ found in one borehole, the deeper, fractured aquifers were also likely to be enriched in these elements. In contrast, the
shallow aquifers are likely to be contaminated with Cl−, NO3
− and K+. Cl− and K+ seem to be locally present in recharge water as shown by their relative higher mean concentrations in the rainy season samples. 相似文献