全文获取类型
收费全文 | 176篇 |
免费 | 1篇 |
专业分类
测绘学 | 6篇 |
大气科学 | 6篇 |
地球物理 | 62篇 |
地质学 | 45篇 |
海洋学 | 18篇 |
天文学 | 34篇 |
综合类 | 1篇 |
自然地理 | 5篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 2篇 |
2014年 | 13篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 14篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
101.
102.
Tibetan area is the most active continental collision zone on earth.Several major earth-quakes occurred around the boundaries of Tibetan plateau and caused massive damages and casualties.The dynamics of this area is not well understood due to the complex structure of Tibet and its sur-rounding area.In this study,a 3D global flow simulation with only viscous rheology is applied to studying the stress distribution in this area,and the interaction between Tibet and its surrounding areas is investigated.Finally... 相似文献
103.
Acquiring consumer goods and services in the destination country signifies a different type of immigrant experience. This is especially pertinent in world cities where there is a strong presence of ethnic economies and where co-ethnic businesses and mainstream businesses compete against each other. The consumption pattern of immigrants is influenced not only by their pre-migration shopping habits, but also their post-migration transnational behaviour. In this paper, we focus on the consumption experience of Chinese immigrants in Toronto, which hosts one of the largest Chinese ethnic economies outside Asia. Based on a random survey and two focus group discussions, we explore how Chinese immigrants choose between ethnic Chinese and mainstream supermarkets, electronic stores and travel agencies. In theory, Chinese and non-Chinese stores providing similar goods and services are substitutes. The study however reveals intriguing results. Chinese and mainstream travel agencies are substitutes but Chinese and mainstream supermarkets and electronic stores are complements. Such differences reflect the importance of ethnicity and culture in immigrants’ consumption behaviour. The paper provides new evidence on immigrant integration in the domain of consumption and contributes a consumer perspective to the literature on ethnic economy and transnationalism. 相似文献
104.
105.
Carme Boix Gianluca Frijia Vicent Vicedo Josep M. Bernaus Matteo Di Lucia Mariano Parente Esmeralda Caus 《Cretaceous Research》2011,32(6):806-822
The Upper Cretaceous La Cova limestones (southern Pyrenees, Spain) host a rich and diverse larger foraminiferal fauna, which represents the first diversification of K-strategists after the mass extinction at the Cenomanian–Turonian boundary.The stratigraphic distribution of the main taxa of larger foraminifera defines two assemblages. The first assemblage is characterised by the first appearance of lacazinids (Pseudolacazina loeblichi) and meandropsinids (Eofallotia simplex), by the large agglutinated Montsechiana montsechiensis, and by several species of complex rotalids (Rotorbinella campaniola, Iberorotalia reicheli, Orbitokhatina wondersmitti and Calcarinella schaubi). The second assemblage is defined by the appearance of Lacazina pyrenaica, Palandrosina taxyae and Martiguesia cyclamminiformis.A late Coniacian-early Santonian age was so far accepted for the La Cova limestones, based on indirect correlation with deep-water facies bearing planktic foraminifers of the Dicarinella concavata zone. Strontium isotope stratigraphy, based on many samples of pristine biotic calcite of rudists and ostreids, indicates that the La Cova limestones span from the early Coniacian to the early-middle Santonian boundary. The first assemblage of larger foraminifera appears very close to the early-middle Coniacian boundary and reaches its full diversity by the middle Coniacian. The originations defining the second assemblage are dated as earliest Santonian: they represent important bioevents to define the Coniacian-Santonian boundary in the shallow-water facies of the South Pyrenean province.By means of the calibration of strontium isotope stratigraphy to the Geological Time Scale, the larger foraminiferal assemblages of the La Cova limestones can be correlated to the standard biozonal scheme of ammonites, planktonic foraminifers and calcareous nannoplankton. This correlation is a first step toward a larger foraminifera standard biozonation for Upper Cretaceous carbonate platform facies. 相似文献
106.
This study focuses on the development of a system with a spatial database and a webGIS able to store, validate and display the data to assist the decision makers in managing early warning systems for river embankment failure. In order to obtain precise results, it is essential to have a tool with ability of managing a large number of data for checking their reliability and for locating them in the space. In this paper, special emphasis was given in the development of procedures to assess the reliability of the measures. For this purpose, the database includes all the information needed to describe the instrument performance, such as the sand pack size and casing diameter of open-standpipe piezometers for evaluating their time lag, and the calibration curves of transducers with the possibility of their updating. The position of the non-functioning instruments is identified through the analysis of the electrical signal and spatial displays, while the analyses of the redundancy and coherence of measures is used for detecting doubtful data. Database and webGIS were applied to the monitoring data of an embankment of the Adige River in Northern Italy. The database and webGIS system has proved to be a suitable and effective tool for the management and validation of real-time data and periodical field measurements. 相似文献
107.
108.
109.
110.
Lucia Angiolini Andrea Zanchi Stefano Zanchetta Alda Nicora Giovanni Vezzoli 《地学学报》2013,25(5):352-360
Based on its Permian‐Triassic stratigraphic and biotic evolution, we correlate the SE Pamir to the Karakoram terrane, and we consider them equivalent, along with the Central Pamir, to the Qiantang Terrane of Tibet, all of Palaeozoic Gondwanan ancestry. We prove the occurrence of a marked Cimmerian unconformity, documented by lowermost Jurassic deposits suturing intensively faulted and folded Permian and Triassic units, which suggests that the South Pamir collided around the T‐J boundary with the Central Pamir along the Rushan‐Pshart suture. Collision of the Karakoram to the South Pamir happened slightly later along the Wakhan‐Tirich Boundary Zone. Progressive time shifting of deformation can be related to the complex setting of the Cimmerian belt, which was subdivided into minor blocks by incipient oceanic basins, providing strong crustal mobility. 相似文献