全文获取类型
收费全文 | 87篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 18篇 |
地球物理 | 12篇 |
地质学 | 22篇 |
海洋学 | 19篇 |
天文学 | 16篇 |
综合类 | 4篇 |
自然地理 | 2篇 |
出版年
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 11篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1986年 | 1篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有95条查询结果,搜索用时 312 毫秒
41.
42.
Jin Koo Kim Jeong -Ho Park Jung Hwa Choi Kwang Ho Choi Yeong Min Choi Dae Soo Chang Young Seop Kim 《Ocean Science Journal》2007,42(2):61-67
Three barracudina fishes (Paralepididae) were newly recorded from the southern sea of Korea. Lestidium prolixum is characterized
by a single band of luminous ducts on the midventral line and absence of a papilla anterior to the eye. Lestrolepis intermedia
and L. japonica are similar in having a black papilla immediately in front of the eye and two bands of luminous ducts on the
midventral line. However, the dorsal fin of L. intermedia is located more posterior along the body than that of L. japonica,
and L. intermedia have larger number of anal fin rays 42 (vs. 36–40) and vertebrae 95 (vs. 86–87) than L. japonica. 相似文献
43.
The hydrodynamic interaction and mechanical coupling effects of two floating platforms connected by elastic lines are investigated by using a time-domain multi-hull/mooring/riser coupled dynamics analysis program. Particular attention is paid to the contribution of off-diagonal hydrodynamic interaction terms on the relative motions during side-by-side offloading operation. In this regard, the exact method (CMM: combined matrix method) including all the vessel and line dynamics, and the 12×12 hydrodynamic coefficients in a combined matrix is developed. The performance of two typical approximation methods (NHI/No Hydrodynamic Interaction: iteration method between two vessels without considering hydrodynamic interaction effects; SMM/Separated Matrix Method: iteration method between two vessels with partially considering hydrodynamic interaction effects, i.e. ignoring off-diagonal cross-coupling terms in the 12×12 hydrodynamic coefficient matrix) is also tested for the same side-by-side offloading operation in two different environmental conditions. The numerical examples show that there exists significant discrepancy at sway and roll modes between the exact and the approximation methods, which means that the cross-coupling (off-diagonal block) terms of the full hydrodynamic coefficient matrix play an important role in the case of side-by-side offloading operation. Therefore, such approximation methods should be used with care. The fender reaction forces, which exhibit large force with contact but no force without contact, are also numerically modeled in the present time-domain simulation study. 相似文献
44.
Effect of environmental conditions on variation in the sediment-water interface created by complex macrofaunal burrows on a tidal flat 总被引:1,自引:0,他引:1
We quantified the increase in the sediment-water interface created by the burrowing activities of the resident macrofaunal community and its variation with respect to the physical conditions of the habitat on a tidal fat. We investigated environmental factors and dimensions of macrofaunal burrows with respect to tidal height and vegetation during spring and summer at three sites. A resin-casting method was used to quantify the dimensions of all burrows at each site. The dimensions of macrofaunal burrows varied both temporally and spatially and the increase in the sediment-water interface reached a maximum of 311%, ranging from 20 to 255% under different habitat conditions. The sediment-water interface depended on the duration of exposure resulting from tidal height, increased temperatures resulting from seasonality, and marsh plant density. Burrows were deeper and more expansive at both higher tidal levels and higher temperatures in summer. Burrow dimensions were sharply reduced with the disappearance of adult macrofauna in areas where the roots of the marsh plant Suaeda japonica were dense. The significance of this study lies in quantifying the burrow dimensions of the entire macrofaunal community, rather than just a single population, and confirming their spatial and temporal variation with respect to physical conditions of the habitat. Environmental factors responsible for variation in burrow dimensions are discussed. 相似文献
45.
46.
47.
Sang Koo HWANG 《世界地质(英文版)》2002,5(2)
The Andong pluton consists of comagmatic granitoid rocks which constitute outstanding examples of reversely zoned granitoids. The pluton has three lithofacies: hornblende biotite tonalite, biotite granodiorite and porphyritic biotite granite. The zoned pattern forms by locating a tonalite core containing high-temperature mafic assemblages in central part,granodiorite rims in marginal part, and a porphyritic granite cap containing more felsic assemblages in topside of the pluton.Mineral abundances as well as bulk compositions of the granitoids indicate that the interior is enriched in mafic minerals and that it shows higher contents of oxides than the margin and topside. The compositional gradients change gradually with continuity between the lithofacies. The regular compositional variations within the pluton support the argument that the pluton behaved as an individual petrochemical system. Model abundances of the granitoids are in agreement with the bulk compositional gradients, suggesting that no significant interaction with country rocks occurred. Remobilization (resurgence) of deeper parts of the system into the more felsic magmas of the chamber explains the reverse zoning. Fractional crystallization was of importance and probably accounts for the selective removal of the settling phases. The Andong pluton is an example of reversely zoned plutons related by remobilization of more mafic but consanguineous magmas. Large-scale upwelling occurred in the pluton leading to the present arrangement of three lithofacies. It is conceivable that remnants of the reverse zoning become more difficult to discern as the plutonic rocks reach the latest stages of their evolution. In this case, the Andong pluton represents an earlier stage in the evolution of a felsic system that is usually represented by the final stages in normally zoned plutons. 相似文献
48.
Assessing spatial autocorrelation (SA) of statistical estimates such as means is a common practice in spatial analysis and statistics. Popular SA statistics implicitly assume that the reliability of the estimates is irrelevant. Users of these SA statistics also ignore the reliability of the estimates. Using empirical and simulated data, we demonstrate that current SA statistics tend to overestimate SA when errors of the estimates are not considered. We argue that when assessing SA of estimates with error, one is essentially comparing distributions in terms of their means and standard errors. Using the concept of the Bhattacharyya coefficient, we proposed the spatial Bhattacharyya coefficient (SBC) and suggested that it should be used to evaluate the SA of estimates together with their errors. A permutation test is proposed to evaluate its significance. We concluded that the SBC more accurately and robustly reflects the magnitude of SA than traditional SA measures by incorporating errors of estimates in the evaluation. Key Words: American Community Survey, Geary ratio, Moran’s I, permutation test, spatial Bhattacharyya coefficient. 相似文献
49.
Michael C. Cooper Jeffrey A. Newman Benjamin J. Weiner Renbin Yan Christopher N. A. Willmer Kevin Bundy Alison L. Coil † Christopher J. Conselice Marc Davis S. M. Faber Brian F. Gerke Puragra Guhathakurta David C. Koo Kai G. Noeske 《Monthly notices of the Royal Astronomical Society》2008,383(3):1058-1078
Using galaxy samples drawn from the Sloan Digital Sky Survey and the DEEP2 Galaxy Redshift Survey, we study the relationship between star formation and environment at z ∼ 0.1 and 1. We estimate the total star formation rate (SFR) and specific star formation rate (sSFR) for each galaxy according to the measured [O ii ]λ 3727 Å nebular line luminosity, corrected using empirical calibrations to match more robust SFR indicators. Echoing previous results, we find that in the local Universe star formation depends on environment such that galaxies in regions of higher overdensity, on average, have lower SFRs and longer star formation time-scales than their counterparts in lower density regions. At z ∼ 1 , we show that the relationship between sSFR and environment mirrors that found locally. However, we discover that the relationship between total SFR and overdensity at z ∼ 1 is inverted relative to the local relation. This observed evolution in the SFR–density relation is driven, in part, by a population of bright, blue galaxies in dense environments at z ∼ 1 . This population, which lacks a counterpart at z ∼ 0 , is thought to evolve into members of the red sequence from z ∼ 1 to ∼0. Finally, we conclude that environment does not play a dominant role in the cosmic star formation history at z < 1 : the dependence of the mean galaxy SFR on local galaxy density at constant redshift is small compared to the decline in the global SFR space density over the last 7 Gyr. 相似文献
50.
Hyun-Suk Koo Hae-Dong Kim Won-Tae Yun Soon-Hwan Lee 《Asia-Pacific Journal of Atmospheric Sciences》2010,46(1):53-64
The urbanization of Daegu metropolitan region has progressed rapidly over the last 100 years, but changing land-use resulting from that urbanization has also caused the regional circulations to evolve. The effect of 100 years of urbanization on the regional circulations was simulated for the analysis using an A2C (Atmosphere to Computational Fluid Dynamics) model. Calm synoptic conditions and a stable lapse rate were assumed for the initial model atmosphere, with a horizontal grid resolution of 1 km. The simulation demonstrated that land-use changes have affected the Daegu metropolitan area’s regional circulations by deepening the convective boundary layer (CBL) over the urbanized area, resulting in deviations from mean surface temperature and surface wind fields. The last 100 years have seen the following changes in the region: 1) the urbanized area has increased by around 15 times, while the number of forests and paddy fields has rapidly decreased; 2) surface wind speeds have decreased by about 25% and 35% during the day and at night, respectively, and severe changes in wind direction have been noted over the urbanized areas; 3) regional warming has been around 1.5°C and 4°C in the daytime and early morning hours, respectively (in particular, warming in the early morning hours suggests the presence of overnight heat islands), and 4) sensible heat flux and CBL height have increased by about 40 W m?2 and 500 m for the period, respectively. 相似文献