全文获取类型
收费全文 | 113篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 2篇 |
地球物理 | 38篇 |
地质学 | 57篇 |
海洋学 | 7篇 |
天文学 | 7篇 |
自然地理 | 5篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 15 毫秒
111.
Zeynel Fuat Toprak Ebru Eris Necati Agiralioglu Hikmet Kerem Cigizoglu Levent Yilmaz Hafzullah Aksoy Hilal Gonca Coskun Gokhan Andic Ugur Alganci 《洁净——土壤、空气、水》2009,37(7):555-564
The estimation of the monthly mean flow is a critical issue in many water resource development projects. However, in practice the mean flow is not easily determined in ungauged and poorly gauged basins. Therefore, in the literature, various flow estimation methods have been developed recently for mountainous regions which are generally ungauged or poorly gauged basins. In this study a fuzzy logic model based on the Mamdani approach was developed to estimate the flow for poorly gauged mountainous basins. This model was applied to the Solakli Basin which is located in the Eastern Black Sea Region of Turkey. Limited rainfall and flow data are available for this basin. In addition to these variables, the stream and time coefficients were introduced and used as variables for modeling. The data was divided into training and testing phases. The model results were compared with the measured data. The comparison depends on seven statistical characteristics, four different error modes and the contour map method. It was observed that the fuzzy model developed in this study yielded reliable results. 相似文献
112.
113.
An intercomparison of remotely sensed soil moisture products at various spatial scales over the Iberian Peninsula 总被引:1,自引:0,他引:1 下载免费PDF全文
Soil moisture (SM) can be retrieved from active microwave (AM), passive microwave (PM) and thermal infrared (TIR) observations, each having unique spatial and temporal coverages. A limitation of TIR‐based retrievals is a dependence on cloud‐free conditions, whereas microwave retrievals are almost all weather proof. A downside of SM retrievals from PM is the coarse spatial resolution. Although SM retrievals at coarse spatial resolution proved to be valuable for global‐scale and continental‐scale studies, their value for regional‐scale studies remains limited. To increase the use of SM retrievals from PM observations, an existing method to enhance their spatial resolution was applied. We present an intercomparison study over the Iberian Peninsula for three SM products on two different spatial sampling grids. The remotely sensed SM products were also compared with in situ observations from the Remedhus network. Variations between ground data and satellite‐based SM are observed; all three remotely sensed SM products show good agreement to the ground observations. The comparison shows that these ground observations and satellite data are consistent, based on the correlation coefficient (R) and root mean square error (RMSE). The remotely sensed products were intercompared after sampling at 25 × 25 km2 and after applying the smoothing filter‐based intensity modulation (SFIM) downscaling technique at 10 × 10 km2 grids. After the application of the SFIM technique, the SM retrievals from PM observations show better agreement with the other remotely sensed SM products for approximately 40% of the study area. For another 40% of the study area, we found a similar agreement between these product combinations, whereas in extreme environments, both arid and densely vegetated regions, the agreement decreases after the application of the SFIM technique. Agreement between retrievals of absolute SM content from PM and TIR observations is generally high (R = 0.77 for semi‐arid areas). This study enhances our understanding of the remotely sensed SM products for improvements of SM retrieval and merging strategies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
114.
Trace Element Levels in the Groundwater of Mediterranean Coastal Plains – The Case of Silifke,Turkey
The Silifke plain is located near the coast of the Mediterranean Sea in Turkey. The delta in the plain is a highly fertile land that supports the agriculture of more than twenty types of crop. Some trace element content of the groundwater samples taken from the existing wells in this area are analyzed using inductively coupled plasma optical emission spectrometry (ICP‐OES). The mean levels (ppm) of boron (B), barium (Ba), iron (Fe), manganese (Mn), lead (Pb), zinc (Zn), total chromium (TCr), cadmium (Cd), copper (Cu), aluminum (Al), and nickel (Ni) were obtained for the sampling points in the area for four seasons. Groundwater samples taken in the study area don't exhibit significantly elevated levels of these elements during a period of twelve months between December 2007 and November 2008. Furthermore, all of the elements exhibit values lower than 0.005 ppm, with the exception of B, Ba, and Fe. The results demonstrate that although these three elements produce the highest values, most are found to be appropriate for activities such as irrigation and human consumption in terms of trace elements. 相似文献
115.
116.
This study presents results of both field and laboratory tests that have been used to asses liquefaction susceptibilities of the soils in Yalova city, located in the well-known seismically active North Anatolian Fault Zone. Liquefaction potentials of the sub-surface materials in Yalova city were estimated by using the standard penetration test (SPT) method of field testing. The data obtained have been mapped according to susceptibility, and the susceptibility maps based on the geotechnical data indicated a moderate to high susceptibility to liquefaction for the magnitude of earthquake of M=7.4. Both the high groundwater level and the grain size of the soils, in conjunction with the active seismic features of the region, result in conditions favourable to the occurrence of liquefaction. When the surface and near surface geological conditions were taken under consideration, it was seen that the study areas geology is prone to liquefaction having a moderate liquefaction susceptibility. If geologic and geomorphological criteria are considered, it should be understood that the study area as discussed under the regions geology is susceptible to liquefaction. The geotechnical data largely support the geologic-based liquefaction susceptibility of the study area. 相似文献
117.
Indirect estimation of the swelling percent and a new classification of soils depending on liquid limit and cation exchange capacity 总被引:2,自引:0,他引:2
Ik Yilmaz 《Engineering Geology》2006,85(3-4):295-301
This paper describes the dependence of the swell percent (%S) on the soil properties, namely, liquid limit (LL) and cation exchange capacity (CEC). This study provides the statistical model that can be used to obtain an indirect estimation of %S due to CEC and LL. According to the coefficient of correlation (R2 = 0.91), VAF (91.5%) and RMSE (0.727) indices, multiple regression model has a high prediction performance. Although CEC values play an important role in the swelling behaviour of clayey soils, there is no universally accepted simple quantitative swelling potential classification at present. In this paper, a new swelling potential classification and graph, having four respective zones indicating the low, moderate, high, very high swelling potential, was also developed and proposed. This classification will serve to the engineers in order to evaluate the expansivity of the soils, in practice. 相似文献
118.
Gülay Bayramoğlu Ilhami Tuzun Gokce Celik Meltem Yilmaz M. Yakup Arica 《International Journal of Mineral Processing》2006
The potential use of the immobilized microalgae (in Ca-alginate) of Chlamydomonas reinhardtii to remove Hg(II), Cd(II) and Pb(II) ions from aqueous solutions was evaluated using bare Ca-alginate bead as a control system. Ca-alginate beads containing immobilized microalgae were incubated for the uniform growth at 22 °C for 5 days. Effects of pH, temperature, initial concentration of metal ions and biosorbent dosages on the adsorption of Hg(II), Cd(II) and Pb(II) ions were studied. Adsorption of Hg(II), Cd(II) and Pb(II) ions on the immobilized microalgae showed highest values at around pH 5.0 to 6.0. The adsorption equilibrium was represented with Langmuir and Freundlich adsorption isotherms. The adsorption of these ions on the immobilized microalgae followed second-order kinetics and equilibrium was established in about 60 min. The temperature change in the range of 5–40 °C did not affect the adsorption capacities of the immobilized microalgae. The immobilized-algal systems can be regenerated using 2 M NaCl for Hg(II), Cd(II) and Pb(II) ions. 相似文献
119.
Tethyan evolution of Turkey: A plate tectonic approach 总被引:9,自引:0,他引:9
The Tethyan evolution of Turkey may be divided into two main phases, namely a Palaeo-Tethyan and a Neo-Tethyan, although they partly overlap in time. The Palaeo-Tethyan evolution was governed by the main south-dipping (present geographic orientation) subduction zone of Palaeo-Tethys beneath northern Turkey during the Permo-Liassic interval. During the Permian the entire present area of Turkey constituted a part of the northern margin of Gondwana-Land. A marginal basin opened above the subduction zone and disrupted this margin during the early Triassic. In this paper it is called the Karakaya marginal sea, which was already closed by earliest Jurassic times because early Jurassic sediments unconformably overlie its deformed lithologies. The present eastern Mediterranean and its easterly continuation into the Bitlis and Zagros oceans began opening mainly during the Carnian—Norian interval. This opening marked the birth of Neo-Tethys behind the Cimmerian continent which, at that time, started to separate from northern Gondwana-Land. During the early Jurassic the Cimmerian continent internally disintegrated behind the Palaeo-Tethyan arc constituting its northern margin and gave birth to the northern branch of Neo-Tethys. The northern branch of Neo-Tethys included the Intra-Pontide, Izmir—Ankara, and the Inner Tauride oceans. With the closure of Palaeo-Tethys during the medial Jurassic only two oceanic areas were left in Turkey: the multi-armed northern and the relatively simpler southern branches of Neo-Tethys. The northern branch separated the Anatolide—Tauride platform with its long appendage, the Bitlis—Pötürge fragment from Eurasia, whereas the southern one separated them from the main body of Gondwana-Land. The Intra-Pontide and the Izmir—Ankara oceans isolated a small Sakarya continent within the northern branch, which may represent an easterly continuation of the Paikon Ridge of the Vardar Zone in Macedonia. The Anatolide-Tauride platform itself constituted the easterly continuation of the Apulian platform that had remained attached to Africa through Sicily. The Neo-Tethyan oceans reached their maximum size during the early Cretaceous in Turkey and their contraction began during the early late Cretaceous. Both oceans were eliminated mainly by north-dipping subduction, beneath the Eurasian, Sakaryan, and the Anatolide- Tauride margins. Subduction beneath the Eurasian margin formed a marginal basin, the present Black Sea and its westerly prolongation into the Srednogorie province of the Balkanides, during the medial to late Cretaceous. This resulted in the isolation of a Rhodope—Pontide fragment (essentially an island arc) south of the southern margin of Eurasia. Late Cretaceous is also a time of widespread ophiolite obduction in Turkey, when the Bozkir ophiolite nappe was obducted onto the northern margin of the Anatolide—Tauride platform. Two other ophiolite nappes were emplaced onto the Bitlis—Pötürge fragment and onto the northern margin of the Arabian platform respectively. This last event occurred as a result of the collision of the Bitlis—Pötürge fragment with Arabia. Shortly after this collision during the Campanian—Maastrichtian, a subduction zone began consuming the floor of the Inner Tauride ocean just to the north of the Bitlis—Pötürge fragment producing the arc lithologies of the Yüksekova complex. During the Maastrichtian—Middle Eocene interval a marginal basin complex, the Maden and the Çüngüş basins began opening above this subduction zone, disrupting the ophiolite-laden Bitlis—Pötürge fragment. The Anatolide-Tauride platform collided with the Pontide arc system (Rhodope—Pontide fragment plus the Sakarya continent that collided with the former during the latest Cretaceous along the Intra Pontide suture) during the early to late Eocene interval. This collision resulted in the large-scale south-vergent internal imbrication of the platform that produced the far travelled nappe systems of the Taurides, and buried beneath these, the metamorphic axis of Anatolia, the Anatolides. The Maden basin closed during the early late Eocene by north-dipping subduction, synthetic to the Inner-Tauride subduction zone that had switched from south-dipping subduction beneath the Bitlis—Pötürge fragment to north dipping subduction beneath the Anatolide—Tauride platform during the later Palaeocene. Finally, the terminal collision of Arabia with Eurasia in eastern Turkey eliminated the Çüngüş basin as well and created the present tectonic regime of Turkey by pushing a considerable piece of it eastwards along the two newly-generated transform faults, namely those of North and East Anatolia. Much of the present eastern Anatolia is underlain by an extensive mélange prism that accumulated during the late Cretaceous—late Eocene interval north and east of the Bitlis—Pötürge fragment. 相似文献
120.
David Krčmář Marian Marschalko Işık Yilmaz Anna Patschová Katarína Chalupková Tibor Kovács 《Environmental Earth Sciences》2014,72(10):4075-4084
The objective of the article presented herein is to highlight the specific issue of the protection of water sources in the vicinity of golf courses. Currently we have experienced the construction of a large number of golf courses, which are often found in areas where the protection of natural groundwater resources is needed. In this article, limit conditions are specified, which could be used in construction of other golf courses in the world, where there is a potential threat of contamination of groundwater resources. The issue is demonstrated on a case study in the area of a water resource, Rusovce. A major concern of golf courses is the fact that in an apparently clean environment of these anthropogenic structures contamination occurs, resulting from the maintenance, and the current legislation does not address this specific group of areas. These are particularly dangerous substances derived from fertilizer and turf protection, in particular the use of pesticides (insecticides, herbicides, fungicides, acaricides, e.g. nematocides, and related products, such as growth regulators used for plant protection). The results of the modelling at the water source, Rusovce, show that the combination of negative factors (for example, the groundwater table level close to the surface along with extremely high precipitation totals or the areas flooding and the lack of a golf course bedrock sealing) the limit value of 0.100 μg/l of pesticides concentration in groundwater was exceeded up to 0.880 μg/l. Similarly, such excess may occur in the case of an emergency situation (for example, the spilling of the barrel with the pesticide), where the concentration of pesticides in groundwater may be increased up to 0.874 μg/l in standard conditions (without flooding with an average depth of groundwater table level beneath the terrain). But even under a standard level of security for the establishment and operation of a golf course and standard procedures for the maintenance of the lawn, the concentration of pesticides in the wells reached 0.0001 μg/l. 相似文献