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61.
62.
Damien Closson Najib Abou Karaki Musa Jad Hussein Hassan Al-Fugha André Ozer Abdullah Mubarak 《Comptes Rendus Geoscience》2003,335(12):869-879
The Dead Sea shore is affected by major subsidence and sinkholes hazards due to the decrease of the sea level. The frequency of resulting accidents increased during the last four decades. Those phenomena could be at the origin of the catastrophic destruction of a major salt evaporation pond on 22 March 2000. In this paper, we show the main results of eight years of research in gravimetry and radar interferometry devoted to identify potentially hazardous areas, at different scales along the Jordanian Dead Sea coast, from the metric scale (gravimetric approach) to the kilometric one (interferometric approach). To cite this article: D. Closson et al., C. R. Geoscience 335 (2003). 相似文献
63.
TheUBV photometry of the detached F-type eclipsing binary BK Pegasi is presented. The light curve solution by a simple spherical model assumption suggests that a slightly hotter, larger and more luminous primary was eclipsed during the primary minimum. Combined with the radial velocity curves in Popper (1983), it was used to determine anew the system's parameters. The age and the metal abundance of the system were estimated as (3.3 ± 0.2) × 109 yr andz = 0.028 ± 0.003 from a comparison with the new grids of stellar models and the isochrones by Schalleret al. (1993). The distance of the system was estimated as 290 pc. 相似文献
64.
The compression index (Cc) is a necessary parameter for the settlement calculation of clays. However, determination of the compression index from oedometer tests takes a relatively long time and leads to a very demanding experimental working program in the laboratory. Therefore, geotechnical engineering literature involves many studies based on indirect methods such as multiple regression analysis (MLR) and soft computing methods to determine the compression index. This study is aimed to predict the compression index by using extreme learning machine (ELM), Bayesian regularization neural network (BRNN), and support vector machine (SVM) methods. The selected variables for each method are the natural water content (wn), initial void ratio (e0), liquid limit (LL), and plasticity index (PI) of clay samples. Many trials were carried out in order to get the best prediction performance with each model. The application results obtained from the models were also compared based on the correlation coefficient (R), coefficient of efficiency (E), and mean squared error (MSE). The results indicate that the BRNN method has better success on estimation of the compression index compared to the ELM and SVM methods. 相似文献
65.
Natural Hazards - The North Anatolian Fault Zone (NAFZ) between the Arabian, Eurasian and African plates is one of the world’s most dangerous tectonic units. After the 1939 Erzincan... 相似文献
66.
The coastal water quality of Çanakkale Dardanelles (Turkey) was assessed based on bacteriological data and physical–chemical parameters. Total coliform (TC), fecal coliform (FC), and enterococci (ENT) bacteria along with physicochemical parameters were measured monthly up to a year at 12 different sampling sites located through both coastal lines of the strait. The fecal bacteria were abounded at several sampling sites such as B1, B3, G3, and G4 due to direct wastewater discharges and septic leakages or overloading. Storm water runoff and sediment resuspension were important pathways for the transport of coliform and ENT bacteria to the Dardanelles, as the region receives high precipitation and strong winds for most part of the year. The values of pH, temperature, and salinity were in typical ranges for the studied area. The microbiological and physicochemical data were correlated individually and in combination. The best fit correlations for bacterial data were attained between TC and FC or TC and ENT (R = 0.67 or ?0.68), while those for the combined data were obtained for TC with temperature (R = 0.94) and TC with salinity (R = ? 0.70). 相似文献
67.
This paper presents the variations of vibration under different traffic conditions on the Fatih Sultan Mehmet suspension bridge in Istanbul, Turkey.The main intention is to determine the vibration amplifications under heavy-traffic as opposed to no-traffic conditions. This is the first study in this particular area that has been performed on this bridge, over which an average of 200,000 cars pass daily. Two full-scale ambient vibration surveys were carried out on two different days to determine the response of the bridge to diverse traffic conditions. Initial measurements were taken as the bridge experienced heavy stress conditions caused by rush-hour traffic. Secondary measurements were recorded after closing the bridge to traffic. The data were analyzed to gauge the vibration effects of heavy-traffic conditions on the bridge and to determine the effects of different traffic conditions on the free vibration characteristics of the bridge. The analyses were performed utilizing different amplification methods. Results show that there are important differences in the amplifications of the vibration amplitudes. Especially heavy-traffic on the bridge causes the vibration response of the bridge to be intensified in comparison to no-traffic conditions. Additionally, predominant frequencies are shifted as a direct result of traffic load acting on the bridge. Even more importantly and is probably analogous for all long-span bridges, is the fact that any movement causing vibration on the bridge is carried and amplified along its length. These significant amplifications indicate the important effect of varying traffic loads and how the bridge responds to the diverse movements it experiences. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
68.
69.
The city of Burdur, which is built on an alluvium aquifer, is located in one of the most seismically active zones in southwestern
Turkey. The soil properties in the study site are characterized by unconsolidated and water-saturated sediments including
silty, clayey and sandy units, and shallow groundwater level is the other characteristic of the site. Thus, the city is under
soil liquefaction risk during a large earthquake. A resistivity survey including 189 vertical electrical sounding (VES) measurements
was carried out in 2000 as part of a multi-disciplinary project aiming to investigate settlement properties in Burdur city
and its vicinity. In the present study, the VES data acquired by using a Schlumberger array were re-processed with 1D and
2D inversion techniques to determine liquefaction potential in the study site. The results of some 1D interpretations were
compared to the data from several wells drilled during the project. Also, the groundwater level map that was previously obtained
by hydrological studies was extended toward north by using the resistivity data. 2D least-squares inversions were performed
along nine VES profiles. This provided very useful information on vertical and horizontal extends of geologic units and water
content in the subsurface. The study area is characterized by low resistivity distribution (<150 Ωm) originating from high
fluid content in the subsurface. Lower resistivity (3–30 Ωm) is associated with the Quaternary and the Tertiary lacustrine
sediments while relatively high resistivity (40–150 Ωm) is related to the Quaternary alluvial cone deposits. This study has
also shown that the resistivity measurements are useful in the estimation of liquefaction risk in a site by providing information
on the groundwater level and the fluid content in the subsurface. Based on this, we obtained a liquefaction hazard map for
the study area. The liquefaction potential was classified by considering the resistivity distributions from 2D inversion of
the VES profiles, the types of the sediments and the extended groundwater level map. According to this map, the study area
was characterized by high liquefaction hazard risk. 相似文献
70.
Abidin Kaya 《Geotechnical and Geological Engineering》2009,27(2):281-288
A backpropagation artificial neural network (ANN) model is developed to predict the secant friction angle of residual and
fully softened soils, using data reported by Stark et al. (J Geotech Geoenviron Eng ASCE 131:575–588, 2005). In the ANN model, index properties such as liquid limit, plastic limit, activity, clay fraction and effective normal stress
are used as input variables while secant residual friction angle is used as output variable. The model is verified using data
that were not used for model training and testing. The results also indicate that the secant residual friction angle of cohesive
soils can be predicted quite accurately using liquid limit, clay fraction and effective normal stress as input variables with
R
2 = 0.93. The sensitivity analysis results indicate that plastic limit and activity have no appreciable effect on ANN predicted
secant friction angles. The secant friction angle predictions of the ANN model were also compared with those of Stark’s et
al. (2005) curves and the empirical formulas suggested for the same data sets by Wright (Evaluation of soil shear strengths for slope
and retaining wall stability with emphasis on high plasticity clays, 2005). The comparison shows that the ANN model predictions are very close to those suggested by the Stark et al. (2005) curves but much better than the prediction of Wright’s (2005) empirical equations. The results also show that ANN is an alternative powerful tool to predict the secant friction angle
of soils. 相似文献