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51.
The Moelv Tillite is the Late Neoproterozoic Varanger glacial deposit recorded in the Hedmark Group, SE Norway. Paired U–Pb and Lu–Hf data collected on detrital zircons in the Rendalen Formation underlying the Moelv Tillite have identified an uncommon 677 ± 15 to 620 ± 14 Ma population, that constrain the deposition of the Moelv Tillite to be younger than 620 ± 14 Ma. The youngest detrital zircons may be derived from granite magmatism related to the 616 ± 3 Ma Egersund dolerite magmatism, situated in the western part of the Sveconorwegian orogen. The Moelv Tillite, which is not overlain by a cap carbonate, possibly correlates with the c. 580 Ma Squantum-Gaskiers glacial deposits of Avalonia. Available palaeomagnetic data for the Late Neoproterozoic suggest that Baltica was located at intermediate to high latitude between 620 and 555 Ma. 相似文献
52.
53.
Kaveh Khalili-Damghani Bahram Aminzadeh-Goharrizi Saeed Rastegar Babak Aminzadeh-Goharrizi 《International journal of geographical information science》2014,28(12):2390-2416
The aim of Land-use Suitability Analysis and Planning Problem (LSAPP) is to identify the most suitable parcels of land for future land-uses considering several conflicting criteria. LSAPP can be modeled using a variant of a well-known combinatorial optimization problem called Quadratic Assignment Problem (QAP). In this paper, a multi-objective mathematical model is developed for LSAPP based on QAP modeling. The large-size instances of the proposed multi-objective mathematical model are difficult to solve in a reasonable CPU time using exact algorithms. So, an efficient three-phase hybrid solution procedure is proposed. In the first phase, the compensatory objectives are integrated using Analytic Hierarchy Process (AHP) and Decision-Making Trial and Evaluation Laboratory. Then, based on the aforementioned suitability objective function and other spatial objectives and constraints, a multi-objective LSAPP is constructed. Finally, a hybrid multiple objective meta-heuristic algorithm is proposed to solve the LSAPP. The core of the proposed algorithm is based on Scatter Search while Tabu Search and Variable Neighborhood Search are also utilized. The proposed algorithm is equipped with the concepts of Pareto optimality and Veto Threshold, which improve its efficacy. The proposed algorithm is applied on a real LSAPP case study, in ‘Persian Gulf Knowledge Village’, wherein its performance is compared with a well-known evolutionary computation algorithm called Vector Evaluated Genetic Algorithm (VEGA) using comprehensive statistical analysis. A survey on time complexity of the proposed algorithm is also accomplished. The results show that MOSVNS is significantly superior to VEGA both in single and in multi-objective modes. Furthermore, analysis of time complexity of the proposed algorithm shows that it is of polynomial time and can be applied to significantly larger problems with multiple compensatory and non-compensatory objectives. 相似文献
54.
Kuwait was exposed to a severe dust storm on 19 March 2003, the eve of operation ??Iraqi Freedom??. Three days of dust events (19, 26, 27 March) were analyzed for their aerosol optical and physical properties using ground-based and satellite-retrieved measurements. Ground-based measurements of aerosol optical depth (or thickness; AOD or AOT) at 675?nm, ?? 657, ?ngstrom coefficient ?? 936/657, particulate matter of diameter 10???m or less, PM10 (??g/m3), and meteorological parameters were analyzed for March 2003. AOT exceeded 3 for the 3?days of interest and PM10 concentrations reached as high value as 2,457???g/m3 on 19 March dust storm day. Retrieved aerosol characteristics from space using Moderate Resolution Imaging Spectrometer (MODIS) on board Terra and Aqua satellite were examined against ground-based measurements. A strong correlation was found between ground-based measurements of ?? 675 and the Terra-MODIS retrieved AOD550. The synoptic of the dust storm were analyzed and source regions were identified using back trajectory analysis and Total Ozone Mapping Spectrometer Aerosol Index. 相似文献
55.
Probabilistic seismic hazard assessment for Thailand 总被引:3,自引:1,他引:2
Teraphan Ornthammarath Pennung Warnitchai Kawin Worakanchana Saeed Zaman Ragnar Sigbj?rnsson Carlo Giovanni Lai 《Bulletin of Earthquake Engineering》2011,9(2):367-394
A set of probabilistic seismic hazard maps for Thailand has been derived using procedures developed for the latest US National
Seismic Hazard Maps. In contrast to earlier hazard maps for this region, which are mostly computed using seismic source zone
delineations, the presented maps are based on the combination of smoothed gridded seismicity, crustal-fault, and subduction
source models. Thailand’s composite earthquake catalogue is revisited and expanded, covering a study area limited by 0°–30°N
Latitude and 88°–110°E Longitude and the instrumental period from 1912 to 2007. The long-term slip rates and estimates of
earthquake size from paleoseismological studies are incorporated through a crustal fault source model. Furthermore, the subduction
source model is used to model the megathrust Sunda subduction zones, with variable characteristics along the strike of the
faults. Epistemic uncertainty is taken into consideration by the logic tree framework incorporating basic quantities, such
as different source modelling, maximum cut-off magnitudes and ground motion prediction equations. The ground motion hazard
map is presented over a 10 km grid in terms of peak ground acceleration and spectral acceleration at 0.2, 1.0, and 2.0 undamped
natural periods and a 5% critical damping ratio for 10 and 2% probabilities of exceedance in 50 years. The presented maps
give expected ground motions that are based on more extensive data sources than applied in the development of previous maps.
The main findings are that northern and western Thailand are subjected to the highest hazard. The largest contributors to
short- and long-period ground motion hazard in the Bangkok region are from the nearby active faults and Sunda subduction zones,
respectively. 相似文献
56.
The effects of structural modeling (bar slip in lap splice), ground motion selection process (epsilon effect) and size of a structure (number of bays and stories) on the fragility of reinforced concrete ordinary moment resisting frames are investigated. An analytical model is developed to account for bar slip in lap splice, which exhibits good correlation with existing experimental data. Then, incremental dynamic analysis is used to derive the fragility curves for four model structures. The model structures simulate frames with a different number of bays and stories. Finally, the fragility curves are corrected for the epsilon effect. The results show that slip in the lap splice can significantly increase the failure probability, especially for the collapse prevention limit state. At the same time, it is found that spectral shape has a significant impact on the fragility curves. It is also found that accounting for or ignoring bar slip or epsilon effects increases the probability of failure for larger structures. This indicates an unconservative bias in the safety of larger structures. 相似文献
57.
The lithostratigraphic subdivision of the Kuhlan Formation in Yemen is reviewed based on the previous literature and new examination of five widely spaced outcrops in the Kuhlan Affar, Jabal Maswar, Jabal Salab, Wadi Hajar, and Ras Falanj areas. Following the guidelines set by the North American Commission on Stratigraphic Nomenclature, Kuhlan Formation, with an age as latest Triassic to the Middle Jurassic, includes three members, Azzan, Souq, and Hesn, in an ascending order. Azzan member consists mainly of about 40 m of whitish coarse grained sandstone with many conglomeratic horizons. The Souq member is characterized by its reddish to brownish sandstones as well as the presence of polygonal structures at in the central part of this member, with a thickness of about 70 m. The Hesn member consists dominantly (80 m) of whitish sandstones with some marl intercalations at its topmost part. The Kuhlan Formation was deposited in a fluviatile environment. 相似文献
58.
Huang Wei Zhang Y. Joseph Wang Zhengui Ye Fei Moghimi Saeed Myers Edward Yu Haocheng 《Ocean Dynamics》2022,72(3):187-205
Ocean Dynamics - Accurate representation of tides is a pre-requisite for simulating many complex coastal processes. This study examines several most important factors for rigorous validation of... 相似文献
59.
Hamed Noori Hojat Karami Saeed Farzin Seyed Mostafa Siadatmousavi Barat Mojaradi Ozgur Kisi 《Natural Hazards》2018,91(1):221-238
Soil erosion due to surface water is a standout among the serious threat land degradation problem and an hazard environmental destruction. The first stage for every kind of soil conservation planning is recognition of soil erosion status. In this research, the usability of two new techniques remote sensing and geographical information system was assessed to estimate the average annual specific sediments production and the intensity erosion map at two sub-basins of DEZ watershed, southwest of Lorestan Province, Iran, namely Absorkh and Keshvar sub-basins with 19,920 ha, using Modified Pacific Southwest Inter-Agency Committee (MPSIAC) soil erosion model. At the stage of imagery data processing of IRS-P6 satellite, the result showed that an overall accuracy and kappa coefficient were 90.3% and 0.901, respectively, which were considered acceptable or good for imagery data. According to our investigation, the study area can be categorized into three level of severity of erosion: moderate, high, and very high erosion zones. The amount of specific sediments and soil erosion predicted by MPSIAC model was 1374.656 and 2396.574 m3 km?2 year?1, respectively. The areas situated at the center and south parts of the watershed were subjected to significant erosion because of the geology formation and ground cover, while the area at the north parts was relatively less eroded due to intensive land cover. Based on effective of nine factors, the driving factors from high to low impact included: Topography > Land use > Upland erosion > Channel erosion > Climate > Ground cover > Soil > Runoff > Surface geology. The measured sediment yield of the watershed in the hydrometric station (Keshvar station) was approximately 2223.178 m3 km?2 year?1 and comparison of the amount of total sediment yield predicted by model with the measured sediment yield indicated that the MPSIAC model 38% underestimated the observed value of the watershed. 相似文献
60.
Ghasem Mirzaei Adel Soltani Milad Soltani Morad Darabi 《Environmental Earth Sciences》2018,77(16):581
This study is aimed at conducting a hazard-based sustainability gap analysis considering spatial threats driven by floods and landslides, that is, a multi-hazard-based prioritization of the most important cities in Gorganrood Basin, Iran. Two data-mining models were used to assess the spatial probability of flood inundation and landslide occurrence, namely, support vector machine with the radial basis function kernel (SVM-RBF) and maximum entropy (ME). As inputs, a total of 124 flooded locations and 346 landslides with ten flood/landslide predisposing factors were mapped using geoinformatics and organizational data. The random selection method was used to split the flood and landslide inventories into two sets of train and test data. Tolerance index was used to test the multicollinearity among predictors. Validation of the models was carried out using the area under the receiver operating characteristic (ROC) curve (AUC). Finally, TOPSIS was used, as a multi-criteria decision-making model, to make an internal sustainability gap analysis to prioritize the threatened and safe cities. For flood inundation, the AUC values obtained from the test set revealed that the SVM-RBF outperformed ME in terms of predictive power and generalization capacity with the respective areas of 0.831 and 0.796 under the curve. For landslide susceptibility assessment, SVM-RBF again excelled ME in predictive power with the respective values of 0.887 and 0.84. Therefore, the susceptibility maps derived from SVM-RBF, as the premier model, were used for the next stage. Extracting the flood and landslide spatial probability values to 14 city points, the TOPSIS-Solver software made a prioritization using the similarity function to the ideal solution. Accordingly, Aliabad, Minoodasht, and Azadshahr cities, with having the smallest similarity coefficients, were found to be the top three spatially threatened cities in Gorganrood Basin, while Aq Qala, Gomishan, and Gonbad-e Kavus cities were placed at the bottom as the safest cities. This study can be a pivotal point in regional risk-based planning, implementation of further pragmatic measures, and allocation of resources for improving sustainable development most wisely. 相似文献