全文获取类型
收费全文 | 107篇 |
免费 | 1篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 2篇 |
地球物理 | 29篇 |
地质学 | 47篇 |
海洋学 | 3篇 |
天文学 | 15篇 |
综合类 | 1篇 |
自然地理 | 8篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 21篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有108条查询结果,搜索用时 15 毫秒
101.
A suite of synthetic titanomagnetites were prepared with compositions Fe2.6?δTi0.4AlδO4 and Fe2.4?δTi0.6AlδO4 (δ = 0, 0.1, 0.2 in both cases). Ball-milling of the synthesized samples produced material in the magnetic monodomain state as indicated by hysteresis loops and the Lowrie-Fuller test. The coercive force of the specimens depends on the Al concentration and lies in the range 1–2 kOe. The TRM induced in the samples is correspondingly “hard”. The low-field (0–1 Oe) TRM acquisition curve is linear. The higher field TRM-H curve is not in agreement with either monodomain or two-domain theoretical models. 相似文献
102.
A quantitative appraisal of earthquake hazard parameters computed from Gumbel I method for different regions in and around Turkey 总被引:2,自引:1,他引:1
Serkan Öztürk Yusuf Bayrak Hakan Çınar George Ch. Koravos Theodoros M. Tsapanos 《Natural Hazards》2008,47(3):471-495
Useful information concerning the earthquake hazard parameters distributed in Turkey and the adjacent areas are estimated
in the present work. Based on Gumbel’s I distribution parameters we are able to estimate the hazard values of the investigated
area which are the mean return periods, the most probable maximum magnitude in the time period of t-years and the probability for an earthquake occurrence of magnitude ≥M during a time span of t-years. Figures concerning the spatial distribution of probabilities and the return periods are plotted and we considered
them of particular interest for mapping the earthquake hazard in Turkey and the surrounding areas. These figures effectively
produce a brief earthquake hazard atlas. The quantitative appraisal of the hazard parameters is useful for engineers, planners,
etc., because it provides a tool for earthquake resistant design. 相似文献
103.
104.
Natural Hazards - Worldwide studies show that gender is an important variable affecting disaster risk perception and that women have high levels of disaster risk perception. The objective of this... 相似文献
105.
Simon F. B. Tett Richard Betts Thomas J. Crowley Jonathan Gregory Timothy C. Johns Andy Jones Timothy J. Osborn Elisabeth Öström David L. Roberts Margaret J. Woodage 《Climate Dynamics》2007,28(1):3-34
A climate simulation of an ocean/atmosphere general circulation model driven with natural forcings alone (constant “pre-industrial” land-cover and well-mixed greenhouse gases, changing orbital, solar and volcanic forcing) has been carried out from 1492 to 2000. Another simulation driven with natural and anthropogenic forcings (changes in greenhouse gases, ozone, the direct and first indirect effect of anthropogenic sulphate aerosol and land-cover) from 1750 to 2000 has also been carried out. These simulations suggest that since 1550, in the absence of anthropogenic forcings, climate would have warmed by about 0.1 K. Simulated response is not in equilibrium with the external forcings suggesting that both climate sensitivity and the rate at which the ocean takes up heat determine the magnitude of the response to forcings since 1550. In the simulation with natural forcings climate sensitivity is similar to other simulations of HadCM3 driven with CO2 alone. Climate sensitivity increases when anthropogenic forcings are included. The natural forcing used in our experiment increases decadal–centennial time-scale and large spatial scale climate variability, relative to internal variability, as diagnosed from a control simulation. Mean conditions in the natural simulation are cooler than in our control simulation reflecting the reduction in forcing. However, over certain regions there is significant warming, relative to control, due to an increase in forest cover. Comparing the simulation driven by anthropogenic and natural forcings with the natural-only simulation suggests that anthropogenic forcings have had a significant impact on, particularly tropical, climate since the early nineteenth century. Thus the entire instrumental temperature record may be “contaminated” by anthropogenic influences. Both the hydrological cycle and cryosphere are also affected by anthropogenic forcings. Changes in tree-cover appear to be responsible for some of the local and hydrological changes as well as an increase in northern hemisphere spring snow cover.
相似文献
Simon F. B. TettEmail: |
106.
107.
Ticona Rollano Fadia Brown Adam Ellenson Ashley Özkan-Haller H. Tuba Thomson Jim Haller Merrick C. 《Ocean Dynamics》2019,69(10):1165-1179
Ocean Dynamics - In the presence of strong winds, ocean surface waves dissipate significant amounts of energy by breaking. Here, breaking rates and wave-following turbulent dissipation rate... 相似文献
108.
Increasing numerical efficiency of iterative solution for total least-squares in datum transformations 总被引:1,自引:0,他引:1
Cartesian coordinate transformation between two erroneous coordinate systems is considered within the Errors-In-Variables (EIV) model. The adjustment of this model is usually called the total Least-Squares (LS). There are many iterative algorithms given in geodetic literature for this adjustment. They give equivalent results for the same example and for the same user-defined convergence error tolerance. However, their convergence speed and stability are affected adversely if the coefficient matrix of the normal equations in the iterative solution is ill-conditioned. The well-known numerical techniques, such as regularization, shifting-scaling of the variables in the model, etc., for fixing this problem are not applied easily to the complicated equations of these algorithms. The EIV model for coordinate transformations can be considered as the nonlinear Gauss-Helmert (GH) model. The (weighted) standard LS adjustment of the iteratively linearized GH model yields the (weighted) total LS solution. It is uncomplicated to use the above-mentioned numerical techniques in this LS adjustment procedure. In this contribution, it is shown how properly diminished coordinate systems can be used in the iterative solution of this adjustment. Although its equations are mainly studied herein for 3D similarity transformation with differential rotations, they can be derived for other kinds of coordinate transformations as shown in the study. The convergence properties of the algorithms established based on the LS adjustment of the GH model are studied considering numerical examples. These examples show that using the diminished coordinates for both systems increases the numerical efficiency of the iterative solution for total LS in geodetic datum transformation: the corresponding algorithm working with the diminished coordinates converges much faster with an error of at least 10-5 times smaller than the one working with the original coordinates. 相似文献