全文获取类型
收费全文 | 75篇 |
免费 | 5篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 6篇 |
地球物理 | 26篇 |
地质学 | 33篇 |
海洋学 | 4篇 |
天文学 | 6篇 |
综合类 | 1篇 |
自然地理 | 3篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 1篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2004年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1994年 | 1篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有80条查询结果,搜索用时 15 毫秒
51.
Dávid Molnár Pál Sümegi László Makó Péter Cseh Christian Zeeden Janina Nett Frank Lehmkuhl Tünde Törőcsik Balázs P. Sümegi 《第四纪科学杂志》2021,36(8):1353-1363
In this paper, the authors present new palaeoecological and sedimentological results from the Upper Palaeolithic site of Ságvár, Hungary. Simple (abundance and dominance) and advanced (cluster analysis, principal component analysis, correspondence) statistical analyses of malacological results were carried out, determining eight malacological zones (MZs) and the key species of the fauna evolution in the sequence. Furthermore, an age–depth model was calculated via Bayesian modelling using new radiocarbon age data. The accumulation rate (AR) was calculated by deriving data from the age–depth model. The palaeoecological reconstruction indicated a cool/cold climate and chiefly steppe environment, with low loess ARs. Not only the vegetation cover but also the geographical setting of the sequence could have led to the low AR values. However, in the uppermost part of the sequence, during the GS 3 and GS 2.1c stadials, the reconstructed palaeoclimate indicated a warming period. Nevertheless, this contradiction is not unique in the Carpathian Basin. The settled Upper Palaeolithic hunters around 22 300 cal a bp lived in a progressively warming wooded steppe environment, hunting mainly for reindeer. Climate change might have forced them to migrate away, following the reindeer. 相似文献
52.
In this study, graft copolymerization of itaconic acid (IA) and crotonic acid (CA) onto the crosslinked chitosan beads were carried out using ammonium persulfate as initiator. Grafted chitosan beads were characterized by FT‐IR analysis and grafting percentage determination. Grafting efficiency and add‐on percentages values of grafted chitosan beads were determined as 23–29 and 32–47%, respectively. Then, equilibrium isotherms and kinetics of brilliant green adsorption onto grafted chitosan beads were investigated. The results indicated that the pseudo‐second‐order kinetic model fitted better than the data obtained from pseudo‐first‐order model for the adsorption of brilliant green onto grafted chitosan beads. The fit of data for brilliant green (BG) adsorption onto grafted chitosan beads suggested that the Langmuir model gave closer fittings than the Freundlich model. 相似文献
53.
Balázs?KissEmail author Szabolcs?Harangi Theodoros?Ntaflos Paul?R.?D.?Mason Elemér?Pál-Molnár 《Contributions to Mineralogy and Petrology》2014,167(3):986
Ciomadul is the youngest volcano in the Carpathian–Pannonian region produced crystal-rich high-K dacites that contain abundant amphibole phenocrysts. The amphiboles in the studied dacites are characterized by large variety of zoning patterns, textures, and a wide range of compositions (e.g., 6.4–15 wt% Al2O3, 79–821 ppm Sr) often in thin-section scale and even in single crystals. Two amphibole populations were observed in the dacite: low-Al hornblendes represent a cold (<800 °C) silicic crystal mush, whereas the high-Al pargasites crystallized in a hot (>900 °C) mafic magma. Amphibole thermobarometry suggests that the silicic crystal mush was stored in an upper crustal storage (~8–12 km). This was also the place where the erupted dacitic magma was formed during the remobilization of upper crustal silicic crystal mush body by hot mafic magma indicated by simple-zoned and composite amphiboles. This includes reheating (by ~200 °C) and partial remelting of different parts of the crystal mush followed by intensive crystallization of the second mineral population (including pargasites). Breakdown textures of amphiboles imply that they were formed by reheating in case of hornblendes, suggesting that pre-eruptive heating and mixing could take place within days or weeks before the eruption. The decompression rim of pargasites suggests around 12 days of magma ascent in the conduit. Several arc volcanoes produce mixed intermediate magmas with similar bimodal amphibole cargo as the Ciomadul, but in our dacite the two amphibole population can be found even in a single crystal (composite amphiboles). Our study indicates that high-Al pargasites form as a second generation in these magmas after the mafic replenishment into a silicic capture zone; thus, they cannot unambiguously indicate a deeper mafic storage zone beneath these volcanoes. The simple-zoned and composite amphiboles provide direct evidence that significant compositional variations of amphiboles do not necessarily mean variation in the pressure of crystallization even if the Al-tschermak substitution can be recognized, suggesting that amphibole barometers that consider only amphibole composition may often yield unrealistic pressure variation. 相似文献
54.
Blake Byron Walker Cameron Taylor-Noonan Alan Tabbernor T’Brenn McKinnon Harsimran Bal Dan Bradley Nadine Schuurman John J. Clague 《Natural Hazards》2014,74(2):1209-1222
Researchers have recently examined the geographic variability of the vulnerability of populations to earthquakes. These studies focus mainly on the complex modelling of geophysical processes or identification of socio-economically disadvantaged populations. However, no studies to date have integrated different components of vulnerability with metrics of travel distance to hospitals and trauma centres (systemic vulnerability). We argue that this previously unaccounted component is an important conceptual and practical aspect of earthquake vulnerability. Accordingly, this paper presents a multi-criteria model for combining physical, social, and systemic components, moving towards a more comprehensive assessment of vulnerability. An analytic hierarchy process is used to produce a place-specific index of social vulnerability, which we combine with soil liquefaction and amplification index and a road network model for access to hospitals and trauma services. Using a geographic information system, we implemented this model for the Greater Victoria region (483 km2, 2011 population: 345,000) in British Columbia, Canada. Clustering of total vulnerability was found in outlying areas, highlighting the importance of access to trauma centres. We conclude by identifying challenges in measuring earthquake vulnerability and advocate integration of systemic vulnerability components in natural hazards research. 相似文献
55.
Theoretical and Applied Climatology - The study of human biometeorological conditions is becoming increasingly important in climate perception for the improvement of public health system. The... 相似文献
56.
It is important to know the quality of water resources for drinking, domestic and irrigation in the rural area. Because, in recent times, there has been increased demand for water due to population growth and intense agricultural activities, so, hydrogeochemical investigations come into prominence for the groundwater use. The purpose of this paper is to evaluate water quality of Ba?köy springs for both drinking and irrigation purposes. The geochemical processes and quality of springs were followed as seasonal in the study area. In view of geochemical classification, springs are Ca-Mg-HCO3 water type for both seasons. Comparison of geochemical data shows that majority of the spring samples are suitable for drinking water. On the other hand, chemical indexes of springs with various classifications were calculated for irrigation purposes. According to the classifications (electrical conductivity, total dissolved solids, total hardness, salinity hazard, percent sodium, sodium adsorption ratio, residual sodium carbonate, residual sodium bicarbonate, permeability index, potential salinity, soluble sodium percentage, magnesium ratio, and Kelly’s ratio), Ba?köy springs are suitable for irrigation purposes. However, water quality of Çaygözü spring is different the other springs due to the high electrical conductivity and total dissolved solids. Also, groundwater mineralization processes and rock–water interaction are controlled with bivariate diagrams of major elements. 相似文献
57.
58.
Detailed assessment of structural characteristics of Turkish RC building stock for loss assessment models 总被引:1,自引:0,他引:1
. Engin Bal Helen Crowley Rui Pinho F. Gülten Gülay 《Soil Dynamics and Earthquake Engineering》2008,28(10-11):914
Assessment of the seismic vulnerability of the building stock in the earthquake-prone Marmara region of Turkey is of growing importance since such information is needed for reliable estimation of the losses that possible future earthquakes are likely to induce. The outcome of such loss assessment exercises can be used in planning of urban/regional-scale earthquake protection strategies; this is a priority in Turkey, particularly following the destructive earthquakes of 1999. Considering the size of the building inventory, Istanbul and its surrounding area is a case for which it is not easy to determine the structural properties and characteristics of the building stock. In this paper, geometrical, functional and material properties of the building stock in the northern Marmara Region, particularly around Istanbul, have been investigated and evaluated for use in loss estimation models and other types of statistic- or probability-based studies. In order to do that, the existing reinforced concrete (RC) stock has been classified as ‘compliant’ or ‘non-compliant’ buildings, dual (frame-wall) or frame structures and emergent or embedded-beam systems. In addition to the statistical parameters such as mean values, standard deviations, etc., probability density functions and their goodness-of-fit have also been investigated for all types of parameters. Functionalities such as purpose of use and floor area properties have been defined. Concrete properties of existing and recently constructed buildings and also characteristics of 220 and 420 MPa types of steel have been documented. Finally, the financial effects of retrofitting operations and damage repair have been investigated. 相似文献
59.
Automated recognition of quasi‐planar ignimbrite sheets as paleosurfaces via robust segmentation of digital elevation models: an example from the Central Andes
下载免费PDF全文
![点击此处可从《地球表面变化过程与地形》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Balázs Székely Zsófia Koma Dávid Karátson Peter Dorninger Gerhard Wörner Melanie Brandmeier Clemens Nothegger 《地球表面变化过程与地形》2014,39(10):1386-1399
Quasi‐planar morphological surfaces may become dissected or degraded with time, but still retain original features related to their geologic‐geomorphic origin. To decipher the information hidden in the relief, recognition of such features is required, possibly in an automated manner. In our study, using Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM), an existing algorithm has been adapted to recognize quasi‐planar features fulfilling specified criteria. The method has been applied to a study area of the Central Andes with Miocene to Quaternary volcanic edifices, tilted ignimbrite surfaces, and basin‐filling sediments. The result is a surface segmentation, whereas non‐planar features (gullies, tectonic faults, etc.) are sorted out. The main types of geomorphic features that can be distinguished and interpreted are as follows. (1) The west‐dipping western margin of the Altiplano is differentiated into segments of the lower sedimentary cover that of increased erosion by tectonic steepening at intermediate levels, and an upper plane with limited erosion. (2) In the central part of the Western Cordillera, the Oxaya ignimbrite block shows a ‘striped’ bulging pattern that results from a smoothly changing surface dip. This pattern is due to continuous folding/warping of the ignimbrite block possibly related to gravitational movements. (3) To the west, large, uniform planes correspond to flat, smooth, tectonically undisturbed surfaces of young sedimentary cover of the Central Basin. (4) The evolution of Taapaca volcanoes with sector collapse events and cone‐building phases is shown by several segments with overlapping clastic aprons. (5) To the east, on the western margin of the Altiplano, young intermontane basins filled by Upper Miocene sediments show progressively increasing dip toward basin margins, reflected by a circular pattern of the segmentation planes. We show that the segmentation models provide meaningful images and additional information for geomorphometric analysis that can be interpreted in terms of geological and surface evolution models. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
60.
Different morphology of Nuphar lutea in two contrasting aquatic environments and its effect on ecosystem engineering
下载免费PDF全文
![点击此处可从《地球表面变化过程与地形》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jonas Schoelynck Kris Bal Veerle Verschoren Ellis Penning Eric Struyf Tjeerd Bouma Dieter Meire Patrick Meire Stijn Temmerman 《地球表面变化过程与地形》2014,39(15):2100-2108
Aquatic plants (macrophytes) can have a large effect on river hydraulics and geomorphology. Though, the extent to how plant morphological plasticity actively influences these feedbacks has received little scientific attention. The nymphaeid macrophyte species Nuphar lutea (L.) Smith is characterized by a distinct leaf duality. Floating leaves shade most of the submerged leaves thereby limiting light penetration in the water. Despite their apparent negligible photosynthetic role, submerged leaves of N. lutea remain intact during summer and contribute a significant part to the total biomass. Our results indicate that the submerged leaves are crucial in plant–flow interactions and hence in the engineering potential of the plant, i.e. the capacity to locally reduce flow velocities and to promote sedimentation, including organic matter deposition. Plant individuals growing in running river water were compared to individuals from adjacent oxbow lake water. The number and size of submerged leaves were significantly higher for river standing individuals and the accumulated sediment contained significantly more organic matter, total nitrogen and total phosphorus, and was characterized by a lower carbon/nitrogen ratio and a finer grain size. We therefore argue that the submerged N. lutea canopy in rivers has the ability to create a high‐nutrient, low hydrodynamic environment, resembling the conditions found in oxbow lakes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献