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241.
P‐ and S‐wave anisotropy to characterise and quantify damage in media: laboratory experiment using synthetic sample with aligned microcracks
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Damage characterisation in solid media is studied in this work through ultrasonic measurements. A synthetic three‐dimensional printed sample including a system of horizontally aligned microcracks is used. In contrast to other manual fabrication methods presented in the literature, the construction process considered here ensures a better control and accuracy of size, shape, and spatial distribution of the microcrack network in the synthetic sample. The acoustic measurements were conducted through a specific device using triple acoustic sensors, which allows capturing at each incident direction three wave modes. The evolution of the ultrasonic velocities with respect to incident angle accounted for the damage‐induced anisotropy. The experimental results are then compared with some well‐known effective media theories in order to discuss their potential use for the following studies. Finally, we highlighted and compared the accuracy of these theories used for inversion procedure to quantify damage in the medium. 相似文献
242.
The study area located south of the Eastern Pontide metallogenic belt (NE Turkey) has an important potential for valuable and base metallic minerals. Geological, tectonic, geochemical, hydrothermal alteration, mineralogical and fluid inclusion characteristics of ore formations in the region have been studied in detail. The purpose of this study is to combine and analyse the acquired spatial data layers in a geographic information system (GIS) environment using knowledge-driven approaches and to identify prospective areas in terms of mineralization. Moreover, evaluating the performance of different knowledge-driven mineral probability modelling results comparatively and quantitatively constitutes the other goal of the study. As a result, in addition to the known mineralization locations, a number of new prospective and favourable areas have been identified for future detailed studies. In addition, it has been found that the mineral predictive map generated using fuzzy logic-OR method produces the best and successful results compared to others. 相似文献
243.
Yan Shi Min Deng Jianya Gong Chang‐Tien Lu Xuexi Yang Huimin Liu 《Transactions in GIS》2019,23(2):312-333
Spatio‐temporal clustering is a highly active research topic and a challenging issue in spatio‐temporal data mining. Many spatio‐temporal clustering methods have been designed for geo‐referenced time series. Under some special circumstances, such as monitoring traffic flow on roads, existing methods cannot handle the temporally dynamic and spatially heterogeneous correlations among road segments when detecting clusters. Therefore, this article develops a spatio‐temporal flow‐based approach to detect clusters in traffic networks. First, a spatio‐temporal flow process is modeled by combining network topology relations with real‐time traffic status. On this basis, spatio‐temporal neighborhoods are captured by considering traffic time‐series similarity in spatio‐temporal flows. Spatio‐temporal clusters are further formed by successive connection of spatio‐temporal neighbors. Experiments on traffic time series of central London's road network on both weekdays and weekends are performed to demonstrate the effectiveness and practicality of the proposed method. 相似文献
244.
Glacier Extent and Volume Change (1966-9000) on the Su-lo Mountain in Northeastern Tibetan Plateau,China 总被引:2,自引:2,他引:0
The topographic maps of 1:50, 000 scales, aerial photographs taken in 1966, one Landsat image taken in 1999, and SRTM data from 2000 were used to quantify the losses in area and volume of the glaciers on the Su-lo Mountain, in the northeastern Tibetan Plateau, China in the past 30 years. The total glacier area decreased from 492.9 km^2 in 1966 to 458.2 km^2 in 1999. The volume loss of the studied glaciers reached 1.4 km^3 from 1966 to 2000. This agrees with documented changes in other mountain glaciers of the whole Tibetan Plateau. 相似文献
245.
246.
Seventeen lactic acid bacterial strains (LAB) were isolated using MRS agar medium from Jeotgal, a Korean fermented food, purchased
at the Jukdo market of Pohang. To identify the strains isolated, they were tested by examining their cell morphologies, gram-staining,
catalase activity, arginine hydrolase activity, D-L lactate form and carbohydrate fermentation. According to the phenotypic
characteristics, three strains were tent atively identified asLactobacillus spp., ten wereEnterococcus spp. (orStreptococcus spp., orPediococcus spp.) and the rest were Leuconostoc spp. (orWeissella spp.). Five strains among 17 were chosen by preliminary bacteriocin activity test. Four bacterial strains which inhibited
both indicator microorganisms were identified by 16S rRNA sequencing. The results are as follows; Leuconostoc mesenteroides
(HK 4),Leuconostoc mesenteroides (HK 5),Leuconostoc mesenteroides(HK 11),Streptococcus salivarius(HK 8). In order to check LAB which are showing a high survival rate in gut, we investigated three strains inhibiting both
indicator microorganisms in artificial gastric acid and bile juice -all except HK8. The three strains mentioned above grew
in extreme low acid conditions. 相似文献
247.
Determining ‘photosynthetically active radiation’ (PAR) is a key part of calculating phytoplankton productivity in a biogeochemical
model. We explore the daily and seasonal variability in the ratio of PAR irradiance to total irradiance that occurred at Ieodo
Ocean Research Station (IORS) in the East China Sea under clear-sky conditions in 2004 using a simple radiative transfer model
(RTM). Meteorological data observed at IORS and aerosol optical properties derived from Aerosol Robotic Network observations
at Gosan are used for the RTM. Preliminary results suggest that the use of simple PA R irradianceratio values is appropriate
in calculating phytoplankton productivity as follows: an average of 0.44 (±0.01) in January to an average of 0.48 (±0.01)
in July, with average daily variabilities over these periods of about 0.016 (±0.008) and 0.025 (±0.008), respectively. The
model experiments demonstrate that variations in the major controlling input parameters (i.e. solar zenith angle, precipitable
water vapor and aerosol optical thickness) cause PAR irradiance ratio variation at daily and seasonal timescales. Further,
increases (>0.012) in the PAR irradiance ratio just below the sea-surface are positively correlated with high solar zenith
angles and strong wind stresses relative to those just above the sea-surface. 相似文献
248.
Nguyen Ngoc Truc Lena Mihova Toshifumi Mukunoki Duc Minh Do 《Marine Georesources & Geotechnology》2020,38(1):23-39
AbstractThis study conducted a series of laboratory experiments and established numerical models on selected undisturbed soil samples in the Red River Delta (RRD) to determine the effect of change in soils intruded by saline water. The variation in the technical parameters of soils was verified in soils fully saturated by solution of four salt concentrations, that is, 0.0, 9.9, 19.8, and 33.0?g/L. Results show that the content and composition of clay minerals in cohesive soils before and after saline intrusion are unchanged. The same finding is obtained for clay after removing absorbed water layer by using a centrifuge apparatus. The zeta potential and settlement velocity of soils in the RRD increase when salt is added to the saturated solution. Similarly, the deformation of soils increases proportionally with the salt concentrations of that solution. This result is attributed to the linear decrease in deformation modulus. The decrease in modulus versus salinities is nearly consistent for pressure stages from 100 to 400?kPa. The safety factor of bearing capacity also decreases linearly with salinities. The decrease reaches 12.5–16.3% when soils are in the maximum saline solution. All these changes are considered as the degradation of soils in saline media. 相似文献
249.
Experimental evaluation of dynamic characteristics of seesaw energy dissipation system for vibration control of structures
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Seesaw energy dissipation system (SEDS), a vibration control system used to provide enhanced seismic protection, has been proposed and investigated numerically. Because of its complicated arrangement, verification experiments are necessary to demonstrate the SEDS damping capacity. This paper presents the results of experimental investigation of the SEDS using fluid viscous dampers. Free vibration tests are conducted to demonstrate the SEDS damping capacity. Results of the free vibration test show that the SEDS has sufficient damping capacity for reduction of the seismic response of the frames. Parametric experimental investigations of the SEDS were conducted, the results of which demonstrate the effects of the system parameter on the damping capacity. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
250.
Post‐repair effect of column jackets on aftershock fragilities of damaged RC bridges subjected to successive earthquakes
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In light of recent earthquakes, structures damaged during an initial seismic event (mainshock) may be more vulnerable to severe damage and collapse during a subsequent event (aftershock). In this paper, a framework for the development of aftershock fragilities is presented; these aftershock fragilities define the likelihood that a bridge damaged during an initial event will exhibit a given damage state following one or more subsequent events. The framework is capable of (i) quantifying the cumulative damage of unrepaired bridges subjected to mainshock–aftershock sequences (effect of multiple earthquakes) and (ii) evaluating the effectiveness of column repair schemes such as steel and fiber‐reinforced‐polymer jackets (post‐repair effect of jackets). To achieve this aim, the numerical model of repaired columns is validated using existing experimental results. A non‐seismically designed bridge is chosen as a case study and is modeled for three numerical bridge models: a damaged (but unrepaired) bridge model, and two bridge models with columns repaired with steel and fiber‐reinforced polymer jackets. A series of back‐to‐back dynamic analyses under successive earthquakes are performed for each level of existing damage. Using simulated results, failure probabilities of components for multiple limit states are computed for each bridge model and then are used to evaluate the relative vulnerability of components associated with cumulative damage and column repair. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献