全文获取类型
收费全文 | 211篇 |
免费 | 4篇 |
国内免费 | 4篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 18篇 |
地球物理 | 44篇 |
地质学 | 66篇 |
海洋学 | 33篇 |
天文学 | 40篇 |
综合类 | 3篇 |
自然地理 | 13篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 16篇 |
2012年 | 13篇 |
2011年 | 14篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 11篇 |
2006年 | 5篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 31 毫秒
51.
Investigation of the dynamic behaviour of a storage tank with different foundation types focusing on the soil‐foundation‐structure interactions using centrifuge model tests
下载免费PDF全文
![点击此处可从《地震工程与结构动力学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Heon‐Joon Park Jeong‐Gon Ha Sun‐Yong Kwon Moon‐Gyo Lee Dong‐Soo Kim 《地震工程与结构动力学》2017,46(14):2301-2316
This paper proposes a dynamic centrifuge model test method for the accurate simulation of the behaviours of a liquid storage tank with different types of foundations during earthquakes. The method can be used to determine the actual stress conditions of a prototype storage‐tank structure. It was used in the present study to investigate the soil‐foundation‐structure interactions of a simplified storage tank under two different earthquake motions, which were simulated using a shaking table installed in a centrifuge basket. Three different types of foundations were considered, namely, a shallow foundation, a slab on the surface of the ground connected to piles and a slab with disconnected piles. The test results were organised to compare the ground surface and foundation motions, the slab of foundation and top of structure motions and the horizontal and vertical motions of the slab, respectively. These were used to establish the complex dynamic behaviours of tank models with different foundations. The effects of soil–foundation–structure interaction with three foundation conditions and two different earthquake motions are focused and some important factors, that should be considered for future designs are also discussed in this research. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
52.
Sanjay Kumar Navin Kumar Dwivedi R. P. Sharma Y.-J. Moon 《Astrophysics and Space Science》2018,363(10):204
We present an analytical model to explore the magnetic field turbulent spectrum by coupled high-frequency kinetic Alfvén wave (KAW) and slow mode of Alfvén wave (AW). The spectrum is computed as a realization of energy cascades from larger to smaller scales for a specific case of solar wind plasma at 1 AU. A two-fluid technique is implemented for the derivation of model equations leading two wave modes. These coupled, nonlinear equations are solved numerically. The nonlinearity in the system arises due to nonlinear ponderomotive force, which is believed to be responsible for the wave localization and magnetic islands formation. The numerical results show that the magnetic islands grow with time and attain a quasi-steady state after the modulation instability is saturated. The magnetic field spectrum and associated spectral indices are computed near the time of saturation of instability. The simulated spectrum in dispersion region follows a power-law with an index of ?2.5. The steeper spectrum could be attributed as energy transfer from larger to smaller scales and helps to study turbulence in solar wind. The magnetic field spectrum and spectral index show a good agreement with the observation of solar wind turbulent spectra. 相似文献
53.
Chemical weathering in the Hong (Red) River basin: Rates of silicate weathering and their controlling factors 总被引:3,自引:0,他引:3
The Hong (Red) River drains the prominent Red River Fault Zone that has experienced various tectonic activities—intrusion of magma, exhumation of basement rocks, and influx of thermal waters—associated with the Cenozoic collision of India and Eurasia. We report dissolved major element and Sr isotope compositions of 43 samples from its three tributary systems (Da, Thao/Hong main channel, and Lo) encompassing summer and winter seasons. Carbonic acid ultimately derived from the atmosphere is the main weathering agent, and sulfuric acid from pyrite oxidation plays a minor role. Seasonality is manifested in higher calcite saturation index and Mg/TZ+ and lower Ca/Mg in summer, suggesting calcite precipitation, and in higher Si/(Na∗ + K) ratios in summer suggesting more intensive silicate weathering. We quantified the input from rain, evaporite, carbonate, and silicate reservoirs using forward and inverse models and examined the robustness of the results. Carbonate dissolution accounts for a significant fraction of total dissolved cations (55-97%), and weathering of silicates makes a minor contribution (1-40%). Our best estimate of the spatially averaged silicate weathering rate in the Hong basin is 170 × 103 mol/km2/yr in summer and 51 × 103 mol/km2/yr in winter. We tested for correlations between the rate of CO2 consumption by silicate weathering and various climatic (air temperature, precipitation, runoff, and potential evapotranspiration) and geologic (relief, elevation, slope, and lithology) parameters calculated using GIS. Clear correlations do not emerge (except for ?CO2 and runoff in winter) which we attribute to the complex geologic setting of the area, the seasonal regime change from physical-dominant in summer to chemical-dominant in winter, and the incoherent timescales involved for the different parameters tested. 相似文献
54.
Dependence of Waterline Mapping on Radar Frequency Used for SAR Images in Intertidal Areas 总被引:1,自引:0,他引:1
Kim D.-J. Moon W. M. Park S.-E. Kim J.-E. Lee H.-S. 《Geoscience and Remote Sensing Letters, IEEE》2007,4(2):269-273
Waterline detection in the intertidal areas was investigated through synthetic aperture radar (SAR) images and field measurements. Two valuable facts were found in this letter: 1) A discrepancy of waterlines between L- and P-band airborne SAR images was discovered and investigated through precise global positioning system measurements and the theory of the SAR imaging mechanism. In the intertidal areas having low slopes, the Bragg waves resonant with the radar signal can reside in different depths depending on the radar frequency, with the result that the boundary between water and land can be mapped differently in the respective SAR images. 2) Intertidal areas covered with a water film present low radar backscatter in SAR images, which can cause mislocation of waterlines 相似文献
55.
Hyeoncheol Kim Jong IK Lee Moon Young Chose Moonsup Cho Xiangshen Zheng Haiquing Sang Ji Qiu 《Polar research》2000,19(2):251-260
Ages of six volcanic and plutonic rocks on Barton Peninsula, King George Island, were determined using 40 Ar/39 Ar and K-Ar isotopic systems. The 40 Ar/39 Ar and K-Ar ages of basaltic andesite and diorite range from 48 My to 74 My and systematically decrease toward the upper stratigraphic section. Two specimens of basaltic andesite which occur in the lowermost sequence of the peninsula, however, apparently define two distinct plateau ages of 52-53 My and 119-120 My. The latter is interpreted to represent the primary cooling age of basaltic andesite, whereas the former is interpreted as the thermally-reset age caused by the intrusion of Tertiary granitic pluton. The isochron ages calculated from the isotope correlation diagram corroborate our interpretation based on the apparent plateau ages. It is therefore likely that volcanism was active during the Early Cretaceous on Barton Peninsula. When the K-Ar ages of previous studies are taken into account with our result, the ages of basaltic andesite in the northern part of the Barton Peninsula are significantly older than those in the southern part. Across the north-west-south-east trending Barton fault bounding the two parts, there are significant differences in geochronologic and geologic aspects. 相似文献
56.
ENSO regulation of MJO teleconnection 总被引:1,自引:0,他引:1
The extratropical teleconnections associated with Madden?CJulian Oscillation (MJO) are shown to have an action center in the North Pacific where the pressure anomalies have opposite polarities between the Phase 3 (convective Indian Ocean) and Phase 7 (convective western Pacific) of the MJO. The teleconnection in the same phase of MJO may induce opposite anomalies over East Asia and North America between El Ni?o and La Ni?a years. During MJO Phase 3, a gigantic North Pacific anticyclonic anomaly occurs during La Ni?a, making coastal northeast Asia warmer/wetter than normal, but the west US colder/drier; whereas during El Ni?o the anticyclonic anomaly is confined to the central North Pacific, hence the northwest US experiences warmer than normal weather under influence of a downstream cyclonic anomaly. During Phase 7, an extratropical cyclonic anomaly forms over the northwest Pacific during La Ni?a due to convective enhancement over the Philippine Sea, causing bitter winter monsoon over Japan; whereas during El Ni?o, the corresponding cyclonic anomaly shifts to the northeast Pacific due to enhanced convection over the equatorial central Pacific, which causes warm and wet conditions along the west coast of US and Canada. Further, the presence of ENSO-induced seasonal anomalies can significantly modify MJO teleconnection, but the aforementioned MJO teleconnection can still be well identified. During Phase 3, the MJO teleconnection pattern over North Pacific will be counterbalanced (enhanced) by El Ni?o (La Ni?a)-induced seasonal mean anomalies. During Phase 7, on the other hand, the MJO teleconnection anomalies in the northeastern Pacific will be enhanced during El Ni?o but reduced during La Ni?a; thereby the impacts of MJO teleconnection on the North America is expected to be stronger during El Ni?o than during La Ni?a. 相似文献
57.
Moon HB An YR Park KJ Choi SG Moon DY Choi M Choi HG 《Marine pollution bulletin》2011,62(9):1963-1968
Reports of the occurrence and accumulation patterns of polycyclic aromatic hydrocarbons (PAHs) and synthetic musk compounds (SMCs) in marine mammals are scarce. In this study, the concentrations and accumulation profiles of PAHs and SMCs were determined in blubber from finless porpoises in Korean coastal waters. Total concentrations of PAHs and SMCs ranged from 6.0 to 432 (mean: 160) ng/g lipid weight and from 17 to 144 (mean: 52) ng/g lipid weight, respectively. Residue levels of PAHs were lower than those reported from other studies, while residue levels of SMCs were relatively higher than those reported in other studies. Naphthalene was the most abundant PAH and HHCB was the dominant SMC observed in finless porpoises. The concentrations of PAHs and SMCs were not correlated with each other, but were significantly correlated within the same chemical groups. No correlations were found between body size and residue levels of PAHs and SMCs. 相似文献
58.
Data on the occurrence and accumulation profiles of butyltins (BTs), including tributyltin (TBT), in marine mammals are scarce. This is the first study to investigate residue levels and accumulation patterns of BTs in cetaceans from Korean coastal waters. The total concentrations of BTs (sum of mono- to tri-butyltins) in minke whales (Balaenoptera acutorostrata) and long-beaked common dolphins (Delphinus capensis) ranged from 15.7 to 297 ng/g wet weight (mean: 100 ng/g wet weight) and from 59.0 to 412 ng/g wet weight (mean: 228 ng/g wet weight), respectively. Dibutyltin (DBT) accounted for 63% of the total BTs in all cetacean samples. Significant species-specific differences in BT concentrations, possibly due to the differences in their habitat and diet, were found between the two cetacean species. The concentrations of DBT and TBT in most cetacean samples exceeded the threshold value for cytotoxic effects in cetaceans, implying potentially adverse health risks from exposure to BTs. 相似文献
59.
Stabilization of arsenic-contaminated mine tailings using natural and calcined oyster shells 总被引:1,自引:0,他引:1
Deok Hyun Moon Kyoung-Woong Kim In-Ho Yoon Dennis G. Grubb Dae-Yewn Shin Kyung Hoon Cheong Hyung-Il Choi Yong Sik Ok Jeong-Hun Park 《Environmental Earth Sciences》2011,64(3):597-605
Natural oyster shells (NOS) and calcined oyster shells (COS) were used to immobilize arsenic (As) from contaminated mine tailings.
In addition, a blend of Portland cement (PC)/cement kiln dust (CKD) was used as a stabilizing agent. The Korean Standard Test
(KST) method (1 N HCl extraction) was used to evaluate the effectiveness of the treatment. The experimental results showed
that COS effectively immobilized As in treated mine tailings. Specifically, an As concentration less than 1 mg L−1 was obtained following COS treatment at 25 and 30 wt%. However, all the samples subjected to NOS treatments failed the Korean
warning standard of 1.2 mg L−1 after 28 days of curing. All of the COS-PC treatments were successful meeting the Korean warning standard after 7 days of
curing. However, the PC-only treatment failed to meet the Korean warning standard. Similarly, the CKD-only treatment was failed
to meet the Korean warning standard after 7 days of curing. However, the COS-CKD treatment showed that when the COS content
was greater than 20 wt%, less than 1 mg L−1 of As leachability was obtained. Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) showed needle-like
and torpedo-like Ca–As phases in the COS-treated samples suggesting that As was strongly associated with Ca and O. X-ray absorption
near edge structure (XANES) analyses confirmed that As(V) was prevalent in the tailings and that there were no changes in
As speciation following NOS or COS treatment. 相似文献
60.
Theoretical and Applied Climatology - The studies on poleward expansion of the Hadley circulation have mainly concentrated on linear trends with global warming. There is no consensus on how the... 相似文献