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211.
The load distribution and deflection of large diameter piles are investigated by lateral load transfer method (p–y curve). Special attention is given to the soil continuity and soil resistance using three-dimensional finite element analysis. A framework for determining a p–y curve is calculated based on the surrounding soil stress. The appropriate parametric studies needed for verifying the p–y characteristic are presented in this paper. Through comparisons with results of field load tests, the three-dimensional numerical methodology in the present study is in good agreement with the general trend observed by in situ measurements and thus, represents a realistic soil–pile interaction for laterally loaded piles in clay than that of existing p–y method. It can be said that a rigorous numerical analysis can overcome the limitations of existing p–y methods to some extent by considering the effect of realistic three-dimensional combination of pile–soil forces. 相似文献
212.
Quantitative mineralogical analysis of bulk samples and single particles was carried out on three loess sections of different local climate settings on the Chinese Loess Plateau (CLP). Mineralogy, geochemistry, and single-particle petrography of loess and paleosols are relatively uniform over the CLP. However, in detail, there are mineralogical changes related to eolian process and chemical weathering. Particle-size sorting eastward from western sources led to an eastward increase of the total phyllosilicate contents enriched in fine illitic clay minerals. After deposition, detrital minerals susceptible to chemical weathering were sequentially altered in a progressive fashion with increasing precipitation in the order of calcite, dolomite, biotite, illite, chlorite, amphibole, and plagioclase. The weathering of biotite, chlorite, and illite resulted in a significant increase of expandable phyllosilicate contents. The sequential weathering of the minerals is reflected chemically in the decrease of Na and Mg and the increase of iron oxidation. Mineralogy of the Chinese loess at individual sites reflects the effects of size fractionation during eolian transportation and progressive sequential weathering along the climatic gradient, and it is essential to consider both effects when using mineralogical and dependent chemical data in the paleoclimatic reconstruction of the CLP. 相似文献
213.
Surface geophysical investigations of landslide at the Wiri area in southeastern Korea 总被引:1,自引:1,他引:0
A geophysical survey was undertaken at Wiri area of the Andong in southeastern Korea to delineate subsurface structure and
to detect the fault zone, which affected the 1997 mountain–hill subsidence and subsequent road heaving initiated by the intense
rainfall. Electrical resistivity methods of dipole–dipole array profiling and Schlumberger array sounding and seismic methods
of refraction and reflection profiling were used to map a clay zone, which was regarded as the major factor for the landslide.
The clay zone was identified in electrical resistivity and seismic sections as having low electrical resistivity (<100 Ωm)
and low seismic velocity (<400 m/s), respectively. The clay zone detected by using geophysical methods is well correlated
with its distribution from the trench and drill-core data. The results of the electrical and seismic surveys showed that slope
subsidence was associated with the sliding of saturated clay along a fault plane trending NNW–SSE and dipping 10°–20° SW.
However, the road heaving was caused by the slope movement of the saturated clay along a sub-vertical NNE-trending fault. 相似文献
214.
Euchaetid copepods (Calanoida, Clausocalanoidea) were collected from the southeastern region of Korea and the East/Japan Sea
from June 2007 to August 2008. Seven species were found and redescribed in this study: five species from the genus Euchaeta (E. concinna, E. indica, E. longicornis, E. plana and E. rimana) and two species from the genus Paraeuchaeta (P. elongata and P. russelli). Using scanning electron microscopy, we observed detailed taxonomic features with special references to their genital structure.
The euchaetid copepods show speciesspecific characteristics on their genital structures, in particular on the shapes of genital
operculum and genital flange. Their zoogeographies were also discussed. They can be regarded as an indicator species of the
Tsushima Warm Current and East Sea Intermediate Water. 相似文献
215.
216.
Characterizing Excavation Damaged Zone and Stability of Pressurized Lined Rock Caverns for Underground Compressed Air Energy Storage 总被引:2,自引:2,他引:0
Hyung-Mok Kim Jonny Rutqvist Ju-Hwan Jeong Byung-Hee Choi Dong-Woo Ryu Won-Kyong Song 《Rock Mechanics and Rock Engineering》2013,46(5):1113-1124
In this paper, we investigate the influence of the excavation damaged zone (EDZ) on the geomechanical performance of compressed air energy storage (CAES) in lined rock caverns. We conducted a detailed characterization of the EDZ in rock caverns that have been excavated for a Korean pilot test program on CAES in (concrete) lined rock caverns at shallow depth. The EDZ was characterized by measurements of P- and S-wave velocities and permeability across the EDZ and into undisturbed host rock. Moreover, we constructed an in situ concrete lining model and conducted permeability measurements in boreholes penetrating the concrete, through the EDZ and into the undisturbed host rock. Using the site-specific conditions and the results of the EDZ characterization, we carried out a model simulation to investigate the influence of the EDZ on the CAES performance, in particular related to geomechanical responses and stability. We used a modeling approach including coupled thermodynamic multiphase flow and geomechanics, which was proven to be useful in previous generic CAES studies. Our modeling results showed that the potential for inducing tensile fractures and air leakage through the concrete lining could be substantially reduced if the EDZ around the cavern could be minimized. Moreover, the results showed that the most favorable design for reducing the potential for tensile failure in the lining would be a relatively compliant concrete lining with a tight inner seal, and a relatively stiff (uncompliant) host rock with a minimized EDZ. Because EDZ compliance depends on its compressibility (or modulus) and thickness, care should be taken during drill and blast operations to minimize the damage to the cavern walls. 相似文献
217.
Woong-Seob Jeong Chris P. Pearson † Hyung Mok Lee Soojong Pak Takao Nakagawa 《Monthly notices of the Royal Astronomical Society》2006,369(1):281-294
We present a comprehensive analysis for the determination of the confusion levels for the current and the next generation of far-infrared surveys assuming three different cosmological evolutionary scenarios. We include an extensive model for diffuse emission from infrared cirrus in order to derive absolute sensitivity levels taking into account the source confusion noise due to point sources, the sky confusion noise due to the diffuse emission, and instrumental noise. We use our derived sensitivities to suggest best survey strategies for the current and the future far-infrared space missions Spitzer , AKARI ( ASTRO-F ), Herschel and SPICA . We discuss whether the theoretical estimates are realistic and the competing necessities of reliability and completeness. We find the best estimator for the representation of the source confusion and produce predictions for the source confusion using far-infrared source count models. From these confusion limits considering both source and sky confusions, we obtain the optimal, confusion limited redshift distribution for each mission. Finally, we predict the cosmic far-infrared background (CFIRB), which includes information about the number and distribution of the contributing sources. 相似文献
218.
Woong-Seob Jeong Hyung Mok Lee Soojong Pak Takao Nakagawa Suk Minn Kwon Chris P. Pearson Glenn J. White 《Monthly notices of the Royal Astronomical Society》2005,357(2):535-547
Fluctuations in the brightness of the background radiation can lead to confusion with real point sources. This type of confusion with background emission is relevant when making infrared (IR) observations with relatively large beam sizes, since the amount of fluctuation tends to increase with the angular scale. To quantitively assess the effect of the background emission on the detection of point sources for current and future far-IR observations by space-borne missions such as Spitzer , ASTRO-F , Herschel and Space Infrared Telescope for Cosmology and Astrophysics ( SPICA ), we have extended the Galactic emission map to a higher level of angular resolution than that of the currently available data. Using this high-resolution map, we estimate the sky confusion noise owing to the emission from interstellar dust clouds or cirrus, based on fluctuation analysis and detailed photometry over realistically simulated images. We find that the confusion noise derived by simple fluctuation analysis agrees well with the results from realistic simulations. Although sky confusion noise becomes dominant in long wavelength bands (>100 μm) with 60–90 cm aperture missions, it is expected to be two orders of magnitude lower for the next generation of space missions (with larger aperture sizes) such as Herschel and SPICA . 相似文献
219.
In this study, NSGA‐II is applied to multireservoir system optimization. Here, a four‐dimensional multireservoir system in the Han River basin was formulated. Two objective functions and three cases having different constraint conditions are used to achieve nondominated solutions. NSGA‐II effectively determines these solutions without being subject to any user‐defined penalty function, as it is applied to a multireservoir system optimization having a number of constraints (here, 246), multi‐objectives, and infeasible initial solutions. Most research by multi‐objective genetic algorithms only reveals a trade‐off in the objective function space present, and thus the decision maker must reanalyse this trade‐off relationship in order to obtain information on the decision variable. Contrastingly, this study suggests a method for identifying the best solutions among the nondominated ones by analysing the relation between objective function values and decision variables. Our conclusions demonstrated that NSGA‐II performs well in multireservoir system optimization having multi‐objectives. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
220.
We address the differences in the ways the Instrument Landing System (ILS) and Ground-Based Augmentation System (GBAS) offer approach guidance, and their principles and methods. We perform comparative analysis of the accuracy of deviation between the GBAS Landing System (GLS) and ILS by means of flight tests, using the flight inspection aircraft at Gimpo International Airport. Our results show that the ILS deviation error increases as the distance between the threshold of runway and the aircraft increases; on the other hand, the GLS deviation error is stable, within the range of ±0.5 to ±2 m lateral and vertical deviation, respectively. We also analyze the alignment accuracy of the ILS and GLS based on the evaluation criteria of Category I of the Federal Aviation Administration, and our analysis results confirm that both systems satisfy the requirements (lateral: ±0.1°, vertical: ±0.05°). 相似文献