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131.
R. Abdullah U. Shaanan K. Lynn G. Rosenbaum 《Australian Journal of Earth Sciences》2020,67(2):153-173
AbstractCambrian deformation associated with the Delamerian Orogeny is most evident in the Delamerian Orogen (southwestern Tasmanides) but has also been documented in the Thomson Orogen (northern Tasmanides). The tectonic evolution of the Thomson Orogen in the context of the Delamerian Orogeny is poorly understood. In particular, tectonostratigraphic relationships between the different parts of the Thomson Orogen (Anakie Inlier, Nebine Ridge, and southern Thomson Orogen) are still unclear. New detrital zircon data from the Nebine Ridge revealed an age spectrum that is consistent with published geochronological data from the Anakie Inlier. These results, in conjunction with petrographic observations and the interpretation of geophysical data, suggest that along the eastern part of the Thomson Orogen, the?~?NNE-trending Nebine Ridge represents the southward continuation of the?~?N–S-trending Anakie Inlier. New detrital zircon geochronological data are also presented for metasedimentary rocks from both sides of the Thomson–Lachlan boundary. The results constrain the maximum age of deposition (Ordovician–Devonian), and show that both sides of the Thomson–Lachlan boundary received detritus from a similar provenance. This might suggest that the Thomson–Lachlan boundary did not play a major role as a crustal-scale boundary prior to the Devonian. We speculate that transpressional deformation along this?~?E–W boundary, during the Early Devonian, was responsible for disrupting the original belt that connected the Delamerian Orogen (Koonenberry Belt) with the eastern Thomson Orogen (Nebine Ridge and Anakie Inlier).
- Highlights
The Nebine Ridge is the southward continuation of the Anakie Inlier.
The Anakie Inlier and Nebine Ridge represent a northern segment of the Cambrian Delamerian–Thomson Belt.
~E–W-trending crustal-scale structures at the southern Thomson Orogen were active during Devonian.
132.
A rapid increase in the number of tourists has placed a heavy demand for freshwater on Manukan Island, a small island located
offcoast of Kota Kinabalu, Sabah. Hydrochemical and numerical approaches have been applied in this study to evaluate the groundwater
quality of unconfined aquifer lying in Manukan Island, Sabah, East Malaysia. This is vital to enhance better understanding
about groundwater management. Hydrochemical analysis output indicated NaCl water type in sampling locations. Seawater intrusion
is marked by its relatively high Na+, Mg2+, Cl− and SO4
2− concentrations. Hydrochemical analysis output clearly showed the influence of seawater in groundwater of Manukan Island.
The numerical model output proved the influence of seawater in groundwater of Manukan Island by indicating the upconing process
at the beneath of the pumping well. Current status of seawater intrusion in Manukan Island is about 14.6% of freshwater and
seawater mixing ratio in low lying area of Manukan Island as simulated by SEAWAT-2000 model output. Numerical model SEAWAT-2000
output showed clearly that the upconing process is the possible route of seawater to influence the fresh groundwater aquifer
chemistry in Manukan Island. The results have enhanced the current understanding of seawater intrusion in the study area.
Future studies will focus on using numerical models to simulate and suggest suitable groundwater management plans in Manukan
Island. 相似文献
133.
The recently compiled Turkish strong motion database: preliminary investigation for seismological parameters 总被引:5,自引:0,他引:5
Sinan Akkar Zehra Çağnan Emrah Yenier Özgür Erdoğan M. Abdullah Sandıkkaya Polat Gülkan 《Journal of Seismology》2010,14(3):457-479
Strong motion data recorded by the Turkish national strong motion network has been compiled and processed systematically for
the first time, together with detailed geophysical and geotechnical site measurements for all of its stations. The catalog
information of 18 seismological agencies and other sources were examined to obtain reliable source, geometry, and distance
parameters for each event. The high quality digital and analog strong motion data was processed by a uniform methodology to
remove the high- and low-frequency noise. Currently, the seismological and spectral information of 4,607 strong motion records
are available for use by earth scientists and earthquake engineers. In this article, we present the fundamental features of
this database and explain our methodology in their calculation. We present several comparisons of our database with other
related studies to verify our approach during the computational stage of the seismological parameters. The results confirm
the reliability of our calculations. The database has also enabled us to derive empirical magnitude conversion relationships
to estimate moment magnitude in terms of different magnitude scales. The article ends with a discussion of the likely improvements
in the European accelerometric data through contributions from this strong motion database applicable for seismically active
shallow-crust regions. The findings of this article emphasize the necessity of global strong motion databases in Europe for
better estimation of seismic hazard in regions of similar seismotectonic environment. 相似文献
134.
Modified dynamic programming approach for offline segmentation of long hydrometeorological time series 总被引:3,自引:1,他引:2
Abdullah Gedikli Hafzullah Aksoy N. Erdem Unal Athanasios Kehagias 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(5):547-557
For the offline segmentation of long hydrometeological time series, a new algorithm which combines the dynamic programming with the recently introduced remaining cost concept of branch-and-bound approach is developed. The algorithm is called modified dynamic programming (mDP) and segments the time series based on the first-order statistical moment. Experiments are performed to test the algorithm
on both real world and artificial time series comprising of hundreds or even thousands of terms. The experiments show that
the mDP algorithm produces accurate segmentations in much shorter time than previously proposed segmentation algorithms. 相似文献
135.
Karl W. Bandilla Michael A. Celia Jens T. Birkholzer Abdullah Cihan Evan C. Leister 《Ground water》2015,53(3):362-377
Geologic carbon sequestration (GCS) is being considered as a climate change mitigation option in many future energy scenarios. Mathematical modeling is routinely used to predict subsurface CO2 and resident brine migration for the design of injection operations, to demonstrate the permanence of CO2 storage, and to show that other subsurface resources will not be degraded. Many processes impact the migration of CO2 and brine, including multiphase flow dynamics, geochemistry, and geomechanics, along with the spatial distribution of parameters such as porosity and permeability. In this article, we review a set of multiphase modeling approaches with different levels of conceptual complexity that have been used to model GCS. Model complexity ranges from coupled multiprocess models to simplified vertical equilibrium (VE) models and macroscopic invasion percolation models. The goal of this article is to give a framework of conceptual model complexity, and to show the types of modeling approaches that have been used to address specific GCS questions. Application of the modeling approaches is shown using five ongoing or proposed CO2 injection sites. For the selected sites, the majority of GCS models follow a simplified multiphase approach, especially for questions related to injection and local‐scale heterogeneity. Coupled multiprocess models are only applied in one case where geomechanics have a strong impact on the flow. Owing to their computational efficiency, VE models tend to be applied at large scales. A macroscopic invasion percolation approach was used to predict the CO2 migration at one site to examine details of CO2 migration under the caprock. 相似文献
136.
Jorge Rosas Oliver Lopez Thomas M. Missimer Kapo M. Coulibaly Abdullah H.A. Dehwah Kathryn Sesler Luis R. Lujan David Mantilla 《Ground water》2014,52(3):399-413
Over 400 unlithified sediment samples were collected from four different depositional environments in global locations and the grain‐size distribution, porosity, and hydraulic conductivity were measured using standard methods. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations (e.g., Hazen, Carman‐Kozeny) commonly used to estimate hydraulic conductivity from grain‐size distribution. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values with errors ranging to over 500%. To improve the empirical estimation methodology, the samples were grouped by depositional environment and subdivided into subgroups based on lithology and mud percentage. The empirical methods were then analyzed to assess which methods best estimated the measured values. Modifications of the empirical equations, including changes to special coefficients and addition of offsets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, offshore marine, and river sediments. Estimated hydraulic conductivity errors were reduced to 6 to 7.1 m/day for the beach subgroups, 3.4 to 7.1 m/day for dune subgroups, and 2.2 to 11 m/day for offshore sediments subgroups. Improvements were made for river environments, but still produced high errors between 13 and 23 m/day. 相似文献
137.
Natural Hazards - Design rainfall is widely used in urban infrastructure planning and design such as culverts and urban drainage systems. In design rainfall estimation, one of the primary steps is... 相似文献
138.
Farida Khanam M. Julleh Jalalur Rahman M. Mustafa Alam Rashed Abdullah 《Journal of the Geological Society of India》2017,89(2):155-164
The Sylhet trough located on the north-eastern margin of present Bengal basin, contains ~22 km of Tertiary sediments and well known as a hydrocarbon producing province. A detailed facies characterization of the subsurface Miocene Surma Group sediments (especial emphasis on reservoirs sandstones) from Jalalabad gas field within the Sylhet trough has been done using core log analysis and wireline log (gamma ray) interpretation. Texture and sedimentary structures of the cores suggests that the nine individual lithofacies types which can be grouped together into three facies associations, namely, fine-grained facies associations (FFA), medium-grained facies association (MFA) and coarse-grained facies associations (CFA). Major changes in gamma ray log motifs and various bounding discontinuities indicate six para-sequence sets (basin wide) and twenty eight para-sequences (local environmental changes) within the depth range from 2200-2800 m. Detailed facies analysis of the cores and wireline log reveals that the interbedding facies within the associations in the Surma Group commonly develop small-scale fining-upward (FU) cycles, coarsening-upward (CU) and random intercalations (RD). The sediments of the Surma Group of the Jalalabad field have been interpreted as deposits of the shallow marine to tide-dominated deltaic depositional setting. The cyclic nature of sedimentation pattern of the Surma Group probably records an almost continuous existence of this prograding deltaic regime and a tectonic setting characterized by a mixture of prolonged basin subsidence and regional transgression coupled with sporadic regressive phases. 相似文献
139.
Aftab Alam Khan Wan Hasiah Abdullah Meor Hakif Hassan Khairinizam Iskandar 《Journal of the Geological Society of India》2017,89(2):197-208
Structurally SW Sarawak basin is a southward sloping basement characterized by passive margin tectonic that has undergone through varioius tectonic phases viz., Triassic extension, Cretaceous transpression and Oligo-Miocene compression. Rock types and sedimentation of deeper basin zone situated between Schwaner mountains block to the south and SW Sarawak basin to the north suggest progressive marine sedimentation. E-W trending Cretaceous carbonate platform (CCP) occurs in the SW Sarawak basin signify a shelf zone where shallow marine sedimentation progressed during Cretaceous transpression. Oligo-Miocene volcanics from subduction melts intercepted basin profusely forming northwest-southeast trending continental arc zone derived from partial melting of subducting slab underneath SW Sarawak basin. Back-arc extension prevailed during Oligo-Miocene and formed several extensional features. Oligo-Miocene subduction also resulted in closure and exhumation of Sri Aman marginal sea-basin to the east. SW Sarawak basin is further divided in two sub-basins viz., Senibong to the west and Kuching to the east separated by a northeast trending morphotectonic ridge that signify structural element formed due to shearing. Marine sedimentation progressed in these sub-basins mainly during Triassic–Jurassic while tidal and fluviatile sedimentation progressed during early to mid-Tertiary having total thickness of sediments about 9 km. Basin closure and exhumation is marked mainly by the formation of Cretaceous carbonate build-up that has been intruded and dissected by the Oligo-Miocene volcanics. Senibong and Kuching sub-basins are characterized by wide range of transpressive features, while, Sri Aman marginal sea-basin is characterized by oceanic assemblages, ophiolite, serpentinite and pillow basalt. 相似文献
140.
The effects of orography in indochina on wind, cloud, and rainfall patterns during Typhoon Ketsana (2009) 总被引:1,自引:0,他引:1
The objective of this study is to i) investigate the effects of orography on the rainfall, wind, and cloud systems of the Typhoon Ketsana (2009) in Indochina, ii) determine rainfall distribution patterns and which parts of Indochina were most affected during Typhoon Ketsana, iii) identify trends in the cloud and rainfall distribution patterns and wind flow patterns in the synoptic scale on orographic effects during Typhoon Ketsana. Remote sensing techniques have been used to study the impacts of TCs. Using data from the remote sensing data such as Fengyun 2D (FY-2D) satellite, Global Digital Elevation Model (GDEM) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite, wind information from the Navy Operational Global Atmospheric Prediction System (NOGAPS), and radiosonde data were applied in this study to determine the relationship of the typhoon with the orographic effect. This study provides examples of how the orographic effect is important to weather forecasters, as high mountain ranges were able to influence the distribution of the cloud, rainfall and even wind flow patterns during the typhoon season. This remote sensing technique allows tropical cyclones to be forecasted and their impacts to be defined, and it allows disaster zones to be determined. 相似文献