全文获取类型
收费全文 | 55篇 |
免费 | 4篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 10篇 |
地球物理 | 14篇 |
地质学 | 15篇 |
海洋学 | 4篇 |
天文学 | 12篇 |
自然地理 | 2篇 |
出版年
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 1篇 |
2006年 | 1篇 |
2004年 | 2篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1992年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有59条查询结果,搜索用时 15 毫秒
1.
Jussi Kääriäinen 《Journal of Geodesy》1992,66(3):281-283
Two water tube clinometers are installed in a deep mine in Lohja, Finland. One, lying in an E-W direction, is 177 m long and the other, lying in a N-S direction, is 62 m long. These instruments are used for tidal records and research. Because the station was on the zone of totality of the 1990 solar eclipse, the instruments offered a suitable tool for investigating whether there was any shielding effect on the direction of the vertical. During the eclipse, the resolution of the instruments was increased to 0.00001 and 0.00004, respectively. p ]Recordings and data evaluation are discussed, and the results obtained show that no gravitational shielding was found at the level of the above accuracy. 相似文献
2.
Cenozoic landscape evolution of the Kruger National Park as derived from cosmogenic nuclide analyses
下载免费PDF全文
![点击此处可从《地学学报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christoph Glotzbach Alexander Paape Jussi Baade Bastian Reinwarth Kate Rowntree Jordan Miller 《地学学报》2016,28(5):316-322
In contrast to active tectonic settings, little is known about the potential feedback between surface processes and climate change in tectonically inactive cratonic regions. Here, we studied the driving forces of erosion and landscape evolution in the Kruger National Park in South Africa using cosmogenic nuclide dating. 10Be‐derived catchment‐wide erosion rates (~2 and ~10 mm ka?1) are similar in magnitude to erosion and rock uplift elsewhere in South Africa, suggesting that (1) rock uplift is solely the isostatic response to erosion and (2) the first‐order topography is likely of Cretaceous age. The topographic maturity is promoted by widespread exposure of rocks resistant to erosion. Our data, however, suggest that local variations in rock resistance lead to transient landscape changes, with local increases in relief and erosion rates. 相似文献
3.
Jussi Heikkinen 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(3):267-274
This paper deals with a novel imaging arrangement for special modeling purpose. The method introduced here will take care of the geometrical consistence of photography. It is based on image ray bundles and is meant for conditions where imaging is accomplished inside the object space (e.g. in case of interior model reconstruction). Imaging is designed to be constrained in terms of camera position and orientation and to consist of two image sequences. The image orientations will be resolved by use of LSQ-estimation in heavily overdetermined conditions. The benefits of overdetermination are discussed and the accuracy assessment in a real experiment is published. The accuracy assessment is accomplished with help of exterior reference and stochastic error propagation. 相似文献
4.
5.
6.
Edward P. Laine 《Quaternary Research》1980,14(2):188-198
Interpretation of Deep Sea Drilling Project results and air-gun seismic profiles suggests that about 106 km3 of sediment have been eroded from eastern North America and southern Greenland and deposited in the adjacent North Atlantic since the beginning of continental glaciation. This volume is a minimum estimate which does not account for sediment beneath the continental shelf nor that portion carried south of the Blake-Bahama Outer Ridge by the Western Boundary Undercurrent. It represents erosion of about 100 m of solid rock and indicates that more than 90% of the sediment eroded from these areas was deposited as sands, silts, and clays in the adjacent western North Atlantic. Glaciation accounts for between 55 and 95 m of this average 100 m, and fluvial processes account for the remainder. The documented erosion in part substantiates W. A. White's (1972, Geological Society of America Bulletin83, 1037–1056) hypothesis of deep erosion and exhumation of shield regions, but is not in agreement with the entire volume of erosion implied by his model. 相似文献
7.
S. Laine 《Astrophysics and Space Science》2001,276(2-4):667-674
The most salient features of the barred spiral galaxy NGC 7479 include the unusually strong and long bar, asymmetric spiral
structure and peculiar dust lanes. The central, bar-dominated region has been robbed of neutral atomic gas. The neutral hydrogen
kinematics of the strong western spiral arm are consistent with substantial non-circular motions. In contrast, the molecular
gas is strongly concentrated in the nucleus and along the bar dust lanes. A molecular disc with near-circular motion is found
in the nuclear area. Outside this component, the molecular gas has a strong radial velocity component consistent with inflow.
The velocity gradients across the bar dust lanes show jumps of a few hundred km s-1. A comparison of the dust/gas lane morphology between the observations and numerical simulations suggests that the corotation
radius is at 1.1 times the bar length. I have modelled many of the peculiar morphological and kinematic features in numerical
simulations of a minor merger. The predicted position of the merging companion matches the position of a bright clump in the
bar with perturbed kinematics.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
9.
Climate projections from multi-model ensembles are commonly represented by the multi-model mean (MMM) climate change. As an alternative, various subjectively formulated schemes for performance-based weighting of models have been proposed. Here, a more objective framework for model weighting is developed. A key ingredient of this scheme is a calibration step quantifying the relationship between intermodel similarity in observable climate and intermodel similarity in simulated climate change. Models that simulate the observable climate better are only given higher weight where and when such an intermodel relationship is found, and the difference in weight between better and worse performing models increases with the strength of this relationship. The method is applied to projections of temperature change from the Third Coupled Model Intercomparison Project. First, cross-validation is used to estimate the potential of the method to improve the accuracy of climate change estimates and to search for suitable predictor variables. The decrease in cross-validation error allowed by the weighting is relatively modest but not negligible, and it could potentially be increased if better predictor variables were found. Second, observations are used to weight the models, to study the differences between the weighted mean and MMM estimates of twenty-first century temperature change and the sensitivity of these differences to the predictor variables and observational data sets used. 相似文献
10.
The climate cooling and vegetation changes in the Miocene/Pliocene are generally well documented by various proxy data. Some important ecosystem changes occurred at that time. Palaeobotanical evidence suggests that the Sahara desert first appeared in the Pliocene, whereas in the Miocene North Africa was green. In the present study, we investigate the Late Miocene climate response to the appearance of the Sahara desert from a climate modelling sensitivity experiment. We compare a model experiment, which includes a full set of Late Miocene boundary conditions, with another one using the same boundary conditions except that the North African vegetation refers to the present-day situation. Our sensitivity study demonstrates that the introduction of the Sahara desert leads to a cooling and an aridification in Africa. In addition, we observe teleconnection patterns related to the North African desertification at around the Miocene/Pliocene boundary. From our sensitivity experiment, we observe that the Sahara contributes to a cooling in Central Asia and in North America. As compared to hypsodonty data for Central Asia, an increased aridity is underestimated in the Sahara experiment. Finally, we observe that the introduction of the Sahara leads to a cooling in the northern high latitudes. Hence, our sensitivity experiment indicates that the appearance of the Sahara desert is one piece to better understand Late Cenozoic climate cooling being most pronounced in the high latitudes. 相似文献