全文获取类型
收费全文 | 279篇 |
免费 | 11篇 |
国内免费 | 9篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 41篇 |
地球物理 | 56篇 |
地质学 | 83篇 |
海洋学 | 72篇 |
天文学 | 30篇 |
综合类 | 9篇 |
自然地理 | 3篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 14篇 |
2016年 | 19篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 21篇 |
2012年 | 13篇 |
2011年 | 19篇 |
2010年 | 23篇 |
2009年 | 20篇 |
2008年 | 11篇 |
2007年 | 12篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 6篇 |
2003年 | 13篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有299条查询结果,搜索用时 15 毫秒
1.
2.
Jung-Moon Yoo Young-In Won Young-Jun Cho Myeong-Jae Jeong Dong-Bin Shin Suk-Jo Lee Yu-Ri Lee Soo-Min Oh Soo-Jin Ban 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(5):439-455
Various types of satellite (AIRS/AMSU, MODIS) and ground measurements are used to analyze temperature trends in the four vertical layers (skin/surface, mid-troposphere, and low stratosphere) around the Korean Peninsula (123–132°E, 33–44°N) during the period from September 2002 to August 2010. The ground-based observations include 72 Surface Meteorological Stations (SMSs), 6 radiosonde stations (RAOBs), 457 Automatic Weather Stations (AWSs) over the land, and 5 buoy stations over the ocean. A strong warming (0.052 K yr?1) at the surface, and a weak warming (0.004~0.010 K yr?1) in the mid-troposphere and low stratosphere have been found from satellite data, leading to an unstable atmospheric layer. The AIRS/AMSU warming trend over the ocean surface around the Korean Peninsula is about 2.5 times greater than that over the land surface. The ground measurements from both SMS and AWS over the land surface of South Korea also show a warming of 0.043~0.082 K yr?1, consistent with the satellite observations. The correlation average (r = 0.80) between MODIS skin temperature and ground measurement is significant. The correlations between AMSU and RAOB are very high (0.91~0.95) in the anomaly time series, calculated from the spatial averages of monthly mean temperature values. However, the warming found in the AMSU data is stronger than that from the RAOB at the surface. The opposite feature is present above the mid-troposphere, indicating that there is a systematic difference. Warming phenomena (0.012~0.078 K yr?1) are observed from all three data sets (SMS, AWS, MODIS), which have been corroborated by the coincident measurements at five ground stations. However, it should also be noted that the observed trends are subject to large uncertainty as the corresponding 95% confidence intervals tend to be larger than the observed signals due to large thermal variability and the relatively short periods of the satellitebased temperature records. The EOF analysis of monthly mean temperature anomalies indicates that the tropospheric temperature variability near Korea is primarily linked to the Arctic Oscillation (AO), and secondarily to ENSO (El Niño and Southern Oscillation). However, the low stratospheric temperature variability is mainly associated with Southern Oscillation and then additionally with Quasi-Biennial Oscillation (QBO). Uncertainties from the different spatial resolutions between satellite data are discussed in the trends. 相似文献
3.
Samuel S. P. Shen Ai B. Gurung Hee-S. Oh T. Shu David R. Easterling 《Climatic change》2011,109(3-4):287-317
The daily surface air temperature data are used to assess the climate changes of the contiguous United States during the period of 1901 to 2000. The assessment is made through the first four statistical moments of the daily maximum, minimum, and mean temperature anomalies, the linear trends of the moments, and the changes of the anomalies?? probability density functions. The results on the first moment, i.e., the mean, are compared with the existing ones in terms of intra-annual means and their linear trends. Our first moment results agree with known ones and demonstrate a decrease from the 1930s to the 1960s and an increase from the 1970s to 2000. The temperature fluctuation is the smallest in the 1960s among the decades from 1931 to 2000. The trends of the higher (second-, third- and fourth-order) moments of the mean, maximum, and minimum surface air temperatures are calculated for the periods 1901?C2000, 1910?C1945, 1946?C1975, and 1976?C2000. The results show a decreasing trend of the second- and third-order moments of all the temperatures. The fourth-order moments of the mean and maximum surface air temperatures have increasing trends, but that of the minimum surface air temperature has a decreasing trend. The seasonal histograms of the mean, maximum, and minimum surface air temperatures are calculated for the three periods 1910?C1945, 1946?C1975, and 1976?C2000 for the stations which have the largest trend of maximum daily surface air temperature. An obvious change has been identified in the probability density functions. Among the changes of statistical parameters, the ones for the minimum temperature are larger than those for the maximum and mean temperatures. 相似文献
4.
Ki-Seon Choi Su-Bin Oh Hi-Ryong Byun R. H. Kripalani Do-Woo Kim 《Theoretical and Applied Climatology》2011,103(1-2):81-93
The May North Pacific Oscillation Index and the summer (May and June?CJuly?CAugust??JJA) Effective Drought Index have a strong negative correlation in the East Asian region, particularly in northern China, Korea, and the southwestern regions of Japan (here termed ??Northeast Asia??); this signifies an intensification of the summer drought during positive North Pacific Index (NPI) phase in this region, and the presence of such a phenomenon has been observed in this study. The low-south/high-north anomalous pressure pattern forming in all layers of the troposphere in Northeast Asian region has been a cause of drought. This unusual pressure pattern gives rise to a cold northeasterly and intensifies downward flow and reduces relative humidity. In addition, this cold northeasterly hinders the northward movement of the western North Pacific high and reduces the frequency of tropical cyclones passing through this region, thereby further intensifying drought. 相似文献
5.
6.
Based on performance-based seismic engineering, this paper proposes an optimal seismic retrofit model for steel moment resisting frames (SMRFs) to generate a retrofit scheme at minimal cost. To satisfy the acceptance criteria for the Basic Safety Objective (BSO) specified in FEMA 356, the minimum number of upgraded connections and their locations in an SMRF with brittle connections are determined by evolutionary computation. The performance of the proposed optimal retrofitting model is evaluated on the basis of the energy dissipation capacities, peak roof drift ratios, and maximum interstory drift ratios of structures before and after retrofitting. In addition, a retrofit efficiency index, which is defined as the ratio of the increment in seismic performance to the required retrofitting cost, is proposed to examine the efficiencies of the retrofit schemes derived from the model. The optimal seismic retrofit model is applied to the SAC benchmark examples for threestory and nine-story SMRFs with brittle connections. Using the retrofit efficiency index proposed in this study, the optimal retrofit schemes obtained from the model are found to be efficient for both examples in terms of energy dissipation capacity, roof drift ratio, and maximum inter-story drift ratio. 相似文献
7.
Considering the small land, dense population and poor natural resources, the oceans are important to Korea, but the recognition of oceans has been weak in Korean society. So ocean governance was fragmented in both institution and policies, which resulted in serious problems in the coastal waters and oceans. However, a series of maritime accidents and failures of policies increased the recognition of the coastal waters and resources and led to the establishment of one single ocean-related governmental agency in 1996. Over the last decade, the ocean governance in Korea has been successful and strong. 相似文献
8.
Ho Il Yoon Myung Woo Han Byong-Kwon Park Jae-Kyung Oh Soon-Keun Chang 《Marine Geology》1997,140(3-4):265-282
High-resolution (3.5 kHz and multi-channel) seismic profiles and piston cores were collected from Maxwell Bay and its tributary embayment, Marian Cove, in the South Shetland Islands, Antarctica, during the Korea Antarctic Research Program (1992/93 and 1995/96) to elucidate the glaciomarine sedimentation processes and recent glacial history of the area. Seismic data from Maxwell Bay reveal a rugged bay margin and flattened basin floor covered with well-stratified hemipelagic muds. On the base-of-slope, acoustically transparent debris flows occur, indicating downslope resedimentation of glaciomarine sediments. Despite the subpolar and ice-proximal settings of Marian Cove, the seafloor is highly rugged with a thin sediment drape, suggesting that much of the area has been recently eroded by glaciers. Sediment cores from the cove penetrated three distinct fining-upward lithofacies: (1) basal till in the lower part of the core, accumulated just seaward of the grounding line of the tidewater glacier; (2) interlaminated sand and mud in the middle part, deposited in ice-proximal zone by a combination of episodic subglacial meltwater inflow and iceberg dumping; and (3) pebbly mud in the upper part, deposited in ice-distal zone by both surface meltwater plume and ice-rafting from the glacier front. A reconstruction of the glacial history of these areas since the late glacial maximum shows an ice sheet filling Maxwell Bay in late Wisconsin time and grounding of the tidewater glacier in Marian Cove until about 1300 yr BP. 相似文献
9.
Larval specimens ofHalicampus punctatus were collected off Ulsan and Uljin in December 2002 (three specimens) and off Ulsan in December 2003 (one specimen). These
specimens are characterized by the following morphological characteristics: rings, 14 + 35 = 49; subdorsal rings, 1 + 3 =
4; dorsal fin rays, 19 – 20; pectoral fin rays, 14 – 15; anal fin rays, 9; head length (HL), 5.8 – 6.7 in the standard length;
snout length, 1.9 in HL; snout depth, 3.7 – 5.2 in snout length. The number of caudal fin rays 9 is less than those of the
other species in the same genus 10. Wide stripe bands composed of small pigments are shown in the trunk and the tail. Melanophores
are not found in the dorsal fin, the pectoral fin, and the anal fin except the caudal fin. The supraoccipital crest is on
the head. The frontal ridge is on the dorsal side of front trunk. The blanched ridges on the opercular are fused with a main
ridge like a tree branch. A few branched ridges that are small and narrow on the trunk and the tail are fused with the main
ridges. We report these specimens as the first record in Korea and name them ‘Byeol-silgo-ki’ in Korean. 相似文献
10.
Moung-Jin Lee Jae-Won Choi Hyun-Joo Oh Joong-Sun Won Inhye Park Saro Lee 《Environmental Earth Sciences》2012,67(1):23-37
Ensemble techniques were developed, applied and validated for the analysis of landslide susceptibility in Jinbu area, Korea using the geographic information system (GIS). Landslide-occurrence areas were detected in the study by interpreting aerial photographs and field survey data. Landslide locations were randomly selected in a 70/30 ratio for training and validation of the models, respectively. Topography, geology, soil and forest databases were also constructed. Maps relevant to landslide occurrence were assembled in a spatial database. Using the constructed spatial database, 17 landslide-related factors were extracted. The relationships between the detected landslide locations and the factors were identified and quantified by frequency ratio, weight of evidence, logistic regression and artificial neural network models and their ensemble models. The relationships were used as factor ratings in the overlay analysis to create landslide susceptibility indexes and maps. Then, the four landslide susceptibility maps were used as new input factors and integrated using the frequency ratio, weight of evidence, logistic regression and artificial neural network models as ensemble methods to make better susceptibility maps. All of the susceptibility maps were validated by comparison with known landslide locations that were not used directly in the analysis. As the result, the ensemble-based landslide susceptibility map that used the new landslide-related input factor maps showed better accuracy (87.11% in frequency ratio, 83.14% in weight of evidence, 87.79% in logistic regression and 84.54% in artificial neural network) than the individual landslide susceptibility maps (84.94% in frequency ratio, 82.82% in weight of evidence, 87.72% in logistic regression and 81.44% in artificial neural network). All accuracy assessments showed overall satisfactory agreement of more than 80%. The ensemble model was found to be more effective in terms of prediction accuracy than the individual model. 相似文献