全文获取类型
收费全文 | 240篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 31篇 |
地球物理 | 65篇 |
地质学 | 106篇 |
海洋学 | 8篇 |
天文学 | 18篇 |
综合类 | 1篇 |
自然地理 | 11篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 18篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 4篇 |
1999年 | 4篇 |
1997年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1963年 | 4篇 |
1962年 | 3篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有245条查询结果,搜索用时 31 毫秒
91.
92.
93.
Markus Eckerstorfer Hanne H. Christiansen Stephan Vogel Lena Rubensdotter 《地球表面变化过程与地形》2013,38(5):466-476
Snow cornices grow extensively on leeward edges of plateau mountains in central Svalbard. A dominant wind direction, a snowdrift source area and a sharp slope transition largely control the formation of snow cornices in a barren peri‐glacial landscape. Seasonal snow cornice dynamics control bedrock weathering and erosion in sedimentary bedrock on the Gruvefjellet plateau edge in the valley Longyeardalen. Air, snow and ground temperature sensors, as well as automatic time‐lapse cameras on a leeward facing plateau edge were used to study seasonal cornice dynamics. These techniques allowed for monitoring of cornice accretion, deformation and collapse/melting in great detail. The active layer of the top plateau edge is characterized by high moisture content due to rain before freeze‐up in autumn and cornice meltdown during spring thaw. Thus frost weathering there can be very efficient in this otherwise cold and dry environment. Within the first autumn snowstorms, a vertical fully developed cornice was in place (190 cm thick). The backwall surface beneath the thickest part of the cornice remained in the ice segregation ‘frost cracking window’ for almost nine months. Highly weathered rock material from the plateau edge is thus incorporated into the cornice during cornice accretion. Brittle snow deformation leads to the opening of cornice tension cracks between the cornice mass and the snowpack on the plateau. These cracks are a prerequisite for cornice collapses, and often trigger cornice fall avalanches on the slope beneath. In these open cornice tension cracks, weathered rock debris, plucked from the plateau edge, can be visible, demonstrating the erosional property of the cornices. The cornice will either collapse or melt, resulting in suspended sediment transport downslope by cornice fall avalanche or release as rock fall respectively. Therefore, cornices both promote and trigger high weathering rates on Gruvefjellet, and thus control presently the development of the rockwall free faces and the talus cones. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
94.
Greenhouse gas emissions, energy security and sustainability are three of the greatest contemporary global challenges to mankind today. The Sino-German Group of scientists have composed a special issue, which is a collection of diverse quality scientific works, that will try to elucidate the current developments in CO2 geologic sequestration research to reduce greenhouse emission including measures to monitor surface leakage, groundwater quality and the integrity of caprock, while ensuring a sufficient supply of clean energy. 相似文献
95.
The causes of land-use and land-cover change: moving beyond the myths 总被引:39,自引:0,他引:39
Eric F. Lambin B. L. Turner Helmut J. Geist Samuel B. Agbola Arild Angelsen John W. Bruce Oliver T. Coomes Rodolfo Dirzo Günther Fischer Carl Folke P. S. George Katherine Homewood Jacques Imbernon Rik Leemans Xiubin Li Emilio F. Moran Michael Mortimore P. S. Ramakrishnan John F. Richards Helle Sknes Will Steffen Glenn D. Stone Uno Svedin Tom A. Veldkamp Coleen Vogel Jianchu Xu 《Global Environmental Change》2001,11(4)
Common understanding of the causes of land-use and land-cover change is dominated by simplifications which, in turn, underlie many environment-development policies. This article tracks some of the major myths on driving forces of land-cover change and proposes alternative pathways of change that are better supported by case study evidence. Cases reviewed support the conclusion that neither population nor poverty alone constitute the sole and major underlying causes of land-cover change worldwide. Rather, peoples’ responses to economic opportunities, as mediated by institutional factors, drive land-cover changes. Opportunities and constraints for new land uses are created by local as well as national markets and policies. Global forces become the main determinants of land-use change, as they amplify or attenuate local factors. 相似文献
96.
Ionuţ Iosifescu Enescu Nadia H. Panchaud Magnus Heitzler Cristina M. Iosifescu Enescu Lorenz Hurni 《The Cartographic journal》2013,50(2):125-136
AbstractMercator depicted Croatia on several general maps. In accordance with the level of geographical knowledge, map scales and technical possibilities of the time, Mercator provided a relatively detailed depiction of basic geographical features on these maps. His interest in mapping Croatia was probably motivated by the fact that the Venetian Republic, the Habsburg Monarchy and the Ottoman Empire had fought over this area in the sixteenth century, contributing to the fragmentation of the medieval Croatian State, while at the same time facilitating economic, religious, linguistic, artistic and scientific communication between Central, South East and Mediterranean Europe. Mercator paid special attention to toponyms that enabled geographical objects to be identified and the decoding of cartographic contents. Research into Mercator’s maps has shown that geographical names, among other things, clearly indicate the sources of spatial data that he used. Additionally, geographical names on Mercator’s maps are significant indicators of the linguistic and cultural contacts that were particularly prominent in border areas, for example, along the eastern Adriatic coast, or the courses of the Danube, Sava and Drava. 相似文献
97.
Xianfeng Liu Tammam Hammad Nadia Saiyouri Mahdia Hattab 《Comptes Rendus Geoscience》2012,344(9):461-470
This study aims at investigating the cementation of marine sediments from the Gulf of Guinea by using physicochemical analysis. In order to highlight the presence of cementation in the sediments, three conventional consolidation tests were conducted on intact and remoulded samples. Mercury intrusion porosimetry analyses were then carried out on the specimens taken from samples after consolidation tests. Several physicochemical experimental techniques were used to analyze these cementations, such as cation exchange capacity analysis, batch test, scanning electron microscope imaging coupled with EDS chemical analysis, and thermal analysis. The results seem to indicate that the cementation of these sediments is predominated by the presence of smectite gel between clay aggregates (clusters). Finally, a conceptual sediment microstructural model is proposed to describe the cementation. 相似文献
98.
M.L. Carapezza F. Barberi M. Ranaldi T. Ricci L. Tarchini J. Barrancos C. Fischer D. Granieri C. Lucchetti G. Melian N. Perez P. Tuccimei A. Vogel K. Weber 《Applied Geochemistry》2012
Gas hazard was evaluated in the three most important cold gas emission zones on the flanks of the quiescent Colli Albani volcano. These zones are located above structural highs of the buried carbonate basement which represents the main regional aquifer and the main reservoir for gas rising from depth. All extensional faults affecting the limestone reservoir represent leaking pathways along which gas rises to the surface and locally accumulates in shallow permeable horizons forming pressurized pockets that may produce gas blowout when reached by wells. The gas, mainly composed of CO2 (>90 vol.%), contains appreciable quantities of H2S (0.35–6 vol.%), and both represent a potentially high local hazard. Both gases are denser than air and accumulate near ground where they may reach hazardous concentrations, and lethal accidents frequently occur to animals watering at local ponds. In order to evaluate the rate of degassing and the related hazard, CO2 and H2S diffuse soil flux surveys have been repeatedly carried out using an accumulation chamber. The viscous gas flux of some important discrete emissions has been evaluated and the CO2 and H2S air concentration measured by portable devices and by Tunable Diode Laser profiles. The minimum potential lethal concentration of the two gases (250 ppm for H2S and 8 vol.% for CO2) is 320 times higher for CO2, whereas the CO2/H2S concentration ratio in the emitted natural gas is significantly lower (15–159). This explains why H2S reaches hazardous, even lethal, concentrations more frequently than CO2. A relevant hazard exists for both gases in the depressed zones (channels, excavations) particularly in the non-windy early hours of the day. 相似文献
99.
Oil Spill Risk Assessments (OSRAs) are widely employed to support decision making regarding oil spill risks. This article adapts the ISO-compliant OSRA framework developed by Sepp Neves et al. (J Environ Manag 159:158–168, 2015) to estimate risks in a complex scenario where uncertainties related to the meteo-oceanographic conditions, where and how a spill could happen exist and the risk computation methodology is not yet well established (ensemble oil spill modeling). The improved method was applied to the Algarve coast, Portugal. Over 50,000 simulations were performed in 2 ensemble experiments to estimate the risks due to operational and accidental spill scenarios associated with maritime traffic. The level of risk was found to be important for both types of scenarios, with significant seasonal variations due to the the currents and waves variability. Higher frequency variability in the meteo-oceanographic variables were also found to contribute to the level of risk. The ensemble results show that the distribution of oil concentrations found on the coast is not Gaussian, opening up new fields of research on how to deal with oil spill risks and related uncertainties. 相似文献
100.
Michela De Dominicis Silvia Falchetti Francesco Trotta Nadia Pinardi Luca Giacomelli Ernesto Napolitano Leopoldo Fazioli Roberto Sorgente Patrick J. Haley Jr. Pierre F. J. Lermusiaux Flavio Martins Michele Cocco 《Ocean Dynamics》2014,64(5):667-688
During the Costa Concordia emergency case, regional, subregional, and relocatable ocean models have been used together with the oil spill model, MEDSLIK-II, to provide ocean currents forecasts, possible oil spill scenarios, and drifters trajectories simulations. The models results together with the evaluation of their performances are presented in this paper. In particular, we focused this work on the implementation of the Interactive Relocatable Nested Ocean Model (IRENOM), based on the Harvard Ocean Prediction System (HOPS), for the Costa Concordia emergency and on its validation using drifters released in the area of the accident. It is shown that thanks to the capability of improving easily and quickly its configuration, the IRENOM results are of greater accuracy than the results achieved using regional or subregional model products. The model topography, and to the initialization procedures, and the horizontal resolution are the key model settings to be configured. Furthermore, the IRENOM currents and the MEDSLIK-II simulated trajectories showed to be sensitive to the spatial resolution of the meteorological fields used, providing higher prediction skills with higher resolution wind forcing. 相似文献