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51.
Min Kyung Lee Yong Il Lee Hyoun Soo Lim Jae Il Lee Jeong Heon Choi Ho Il Yoon 《Journal of Paleolimnology》2011,45(2):127-135
Both radiocarbon and optically stimulated luminescence (OSL) dating methods were applied to test their suitability for establishing
a chronology of arid-zone lacustrine sediments using a 5.88-m-long core drilled from Lake Ulaan, southern Mongolia. Although
the radiocarbon and OSL ages agree in some samples, the radiocarbon ages are older than the corresponding OSL ages at the
550-cm depth horizon (late Pleistocene) and in the 100–300-cm interval (early to late Holocene). In the early to late Holocene,
radiocarbon ages are consistently older than OSL ages by 4,100–5,800 years, and in the late Pleistocene by 2,700–3,000 years.
Grain-size analysis of early to late Holocene sediments and one late Pleistocene sediment sample (550-cm depth) indicates
that eolian processes were the dominant sediment-transport mechanism. Also, two late Pleistocene sediments samples (from 400-
to 500-cm depths) are interpreted to have been deposited by both eolian and glaciofluvial processes. Accordingly, the radiocarbon
ages that were older than the corresponding OSL ages during the Holocene seem to have been a consequence of the influx of
14C-deficient carbon delivered from adjacent soils and Paleozoic carbonate rocks by the westerly winds, a process that is also
active today. In addition to the input of old reworked carbon by eolian processes, the late Pleistocene sediments were also
influenced by old carbon delivered by deglacial meltwater. The results of this study suggest that when eolian sediment transport
is suspected, especially in lakes of arid environments, the OSL dating method is superior to the radiocarbon dating method,
as it eliminates a common ‘old-carbon’ error problem. 相似文献
52.
The Changjiang diluted water (CDW) around Jeju Island between 2002 and 2006 in response to external forcings, such as wind, tidal forcing and low river discharge, is studied using a three-dimensional model. The model results suggest that wind largely determines spatial differences of CDW and the freshwater export toward Jeju Island between two years. In 2006, when northwestward wind blows during mid June to mid August, the wind-induced Ekman flow causes a broad northeastward extension of CDW and carries a significant amount of freshwater northeastward Jeju Island in August. On the other hand, in 2002 northward wind during mid July to early August drives the CDW to the southwest of Jeju Island, and thereafter the CDW is mainly advected northeastward along the Cheju Current during mid August when the wind becomes weak. Therefore, the amount of freshwater around Jeju Island increases in September, not in August. The response to tidal forcing shows that tide-induced vertical mixing tends to enhance a meander of CDW around Changjiang Bank and shift the CDW flowing into the Yellow Sea southeastward toward Jeju Island. As a result, the amount of freshwater toward Jeju Island becomes larger than that in no-tides case. The summer low river discharge as a flood control scenario has little influence on the spatial behavior of CDW around Jeju Island although the discharge contributes to the amount of freshwater around Jeju Island. 相似文献
53.
Summary The possibility of climate change in the Korean Peninsula has been examined in view of the general increase in greenhouse
gases. Analyses include changes in annual temperature and precipitation. These analyses are supplemented with our observations
regarding the apparent decrease of forest areas.
It was found that there was a 0.96 °C (0.42 °C per decade) increase in annual mean temperature between 1974 and 1997. The
increase in large cities was 1.5 °C but only 0.58 °C at rural and marine stations. The difference in the mean temperature
between large cities and rural stations was small from 1974 to 1981. However, the difference increased from 1982 to 1997.
In particular, the warming appears most significant in winter. Prior to 1982, the lowest temperatures were often −18 °C in
central Korea, and since then the lowest temperatures have been only −12∼−14 °C. Recently, the minimum January temperature
has increased at a rate of 1.5 °C per decade. It is estimated that the increase of1 °C in annual mean temperature corresponds
to about a 250 km northward shift of the subtropical zone boundary.
The analysis of data from 1906 to 1997 indicates a trend of increasing annual precipitation, an increase of 182 mm during
the 92-year peirod, with large year-to-year variations. More than half of the annual mean amount, 1,274 mm, occurred from
June to September.
Meteorological data and satellite observations suggest that changes have occurred in the characteristics of the quasi-stationary
fronts that produce summer rain. In recent years scattered local heavy showers usually occur with an inactive showery front,
in comparison with the classical steady rain for more than three weeks. For instance, local heavy rainfall, on 6 August 1998
was in the range of 123–481 mm. The scattered convective storms resulted in flooding with a heavy toll of approx. 500 people.
The northward shift of the inactive showery front over Korea, and of a convergence zone in central China, correlate with the
increase in temperature. It has been suggested that the decrease in forest areas and the change in ground cover also contribute
to the warming of the Korean Peninsula.
Received March 16, 2000 相似文献
54.
Mi-Kyung Yoon Mikhail Baykulov Stefan Dümmong Heinz-Jürgen Brink Dirk Gajewski 《International Journal of Earth Sciences》2008,97(5):887-898
The influence of deep crustal processes on basin formation and evolution and its relation to current morphology is not well
understood yet. A key feature to unravel these issues is a detailed seismic image of the crust. A part of the data recorded
by the hydrocarbon industry in the late 1970s and 1980s in the North German Basin were released to the public recently. The
seismic reflection data were recorded down to 15 s two-way travel time. The mean Common Midpoint fold of about 20 is relatively
low compared to contemporary seismic acquisitions. The processing of the 1980s focussed on the sedimentary structures to explore
the hydrocarbon potential of this area. We applied the Common Reflection Surface stack technique to the data sets, which is
well suited for low-fold data. The reprocessing was focussed on the imaging of the subsedimentary crustal range. The reprocessed
images show enhanced reflections, especially in the mid and lower crustal part. Also, the image of the salt structures in
the graben area was improved. Furthermore, the reprocessed images indicate an almost flat Moho topography in the area of the
Glückstadt Graben and an additional lower crustal structure, which can be correlated with a high-density body found in recent
gravity modeling studies. 相似文献
55.
Effects of surface forces and film elasticity on foam stability 总被引:1,自引:0,他引:1
The thin film pressure balance (TFPB) technique was used to determine the surface forces in foam films stabilized with flotation frothers such as n-pentanol, n-octanol, methyl isobutyl carbinol (MIBC), and polypropylene glycol (PPG). The results were compared with the foam stabilities measured experimentally and the film elasticities calculated using a model developed by Wang and Yoon [Wang, L., Yoon, R.-H., 2006a. Role of hydrophobic force in the thinning of foam films containing a nonionic surfactant. Colloids Surfaces A: Physicochem. Eng. Aspects, 282–283, 84–91.]. It was found that foam stabilities are controlled by both film elasticity and disjoining pressure, the relative contributions from each changing with frother type and concentration. At relatively low concentrations, frother dampens the hydrophobic force, an attractive component of the disjoining pressure, that destabilizes foams. At higher concentrations, elasticity plays a more important role in stabilizing foams. 相似文献
56.
57.
Hong-Key Yoon Dr. 《GeoJournal》1991,25(4):387-392
Geomentality is an established and lasting frame (state) of mind regarding the environment. It is necessarily translated into
a geographical behavioral pattern and is reflected in a pattern of cultural landscape. An individual or a group of people
can hold a geomentality about a particular environment. What an architect's plan is to a building, a geomentality is to a
pattern of cultural landscape. Geomentality is ultimately responsible for the development of a cultural landscape pattern.
Determining a geomentality is therefore the key in explaining a pattern of cultural landscape more profoundly than is possible
by some conventional methods. 相似文献
58.
Hong‐Key Yoon 《Geographical review》2016,106(1):136-154
For over a thousand years many settlements in Korea forbid the digging of water‐wells. This custom can be explained using geomancy, which personifies local landscapes or names them after animate or inanimate objects. In ‘sailing boat’ landscapes the digging of water‐wells was prohibited because this was viewed as analogous to making a hole in the bottom of a boat, which would thus bring misfortune to local residents. Based on this geomantic reasoning, people considered the custom of forbidding well digging to be an integral part of the art of geomancy, with its origin in a geomantic belief system. My earlier research sustained this explanation but this paper, which is based on two recent instances of field work, rejects the established view on the custom. The aim of this paper is to critically re‐examine this established view and suggests a new idea that the folk custom of prohibiting well digging in Korea was not originally derived from geomancy, but was conceived from a non‐geomantic indigenous Korean idea and have become linked to geomancy through the enforcement process of practicing the custom in traditional Korean society. 相似文献
59.
The tsunamis that have occurred in many places around the world over the past decades have taken a heavy toll on human lives and property. The eastern coast of the Korean Peninsula is not safe from tsunamis and has sustained tsunami damage in the past. The aim of this study is to review the past, present, and future of some aspects of tsunami research in Korea. A composite numerical model comprising propagation and inundation models is described. The paper also covers tsunami mitigation efforts in Korea, and a tsunami hazard map is developed and introduced. 相似文献
60.
Kim IC Chang SY Williams TD Ja Kim Y Yoon YD Lee YS Park EH Lee JS 《Marine environmental research》2004,58(2-5):687-691
We cloned the vitellogenin gene from the self-fertilizing fish Rivulus marmoratus, and sequenced 12,326 bp. The number of exons of R. marmoratus and rainbow trout vitellogenin genes were different, and also the splicing junctions are different throughout most of the exons and introns but the amino acid similarity of R. marmoratus vitellogenin gene to other species was rather high. In promoter region of R. marmoratus vitellogenin gene, there were several E2 binding sites and the estrogen response element (ERE). We discuss here the gene structure and expression of R. marmoratus vitellogenin gene. 相似文献