全文获取类型
收费全文 | 2533篇 |
免费 | 76篇 |
国内免费 | 70篇 |
专业分类
测绘学 | 74篇 |
大气科学 | 408篇 |
地球物理 | 566篇 |
地质学 | 625篇 |
海洋学 | 666篇 |
天文学 | 195篇 |
综合类 | 40篇 |
自然地理 | 105篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 22篇 |
2021年 | 38篇 |
2020年 | 45篇 |
2019年 | 50篇 |
2018年 | 126篇 |
2017年 | 114篇 |
2016年 | 169篇 |
2015年 | 80篇 |
2014年 | 174篇 |
2013年 | 238篇 |
2012年 | 113篇 |
2011年 | 150篇 |
2010年 | 160篇 |
2009年 | 148篇 |
2008年 | 142篇 |
2007年 | 144篇 |
2006年 | 110篇 |
2005年 | 104篇 |
2004年 | 104篇 |
2003年 | 72篇 |
2002年 | 55篇 |
2001年 | 51篇 |
2000年 | 34篇 |
1999年 | 34篇 |
1998年 | 26篇 |
1997年 | 18篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 2篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
排序方式: 共有2679条查询结果,搜索用时 15 毫秒
921.
The purpose of this study was to evaluate the effects of climate change on the drought and flood risks of a multipurpose dam. To achieve this, A2 climate change scenarios of RegCM3 were collected about Chungju Dam in Korea. To analyze drought risks, weather data obtained by the statistical downscaling method were entered to produce runoff series by runoff modeling and water balance was analyzed based on water use scenarios to review changes in the storage volume under climate change. To analyze flood risks, changes in water levels of the dam in future flood seasons were reviewed based on the current dam operation method. The results of the review indicated that both the drought and the flood risks of the dam would increase in the future. The reason was considered to be the movement of the flood season’s runoff characteristics from July and August to August and September because of climate change. Therefore, for climate change adaptation planning, not only quantitative changes in hydrologic values but also changes in temporal characteristics should be considered and given importance. 相似文献
922.
Hong Seok-Hwi Yoo Dong-Geun Lee Gwang-Soo Kim Jin Cheul Yi Sangheon Kim Gil-Young Bahk Jang-Jun Yu Shin 《Marine Geophysical Researches》2022,43(4):1-18
Marine Geophysical Research - This study entails the characterization of the depositional environment of the Hupo Basin shelf. By means of sedimentary structure analysis, grain size, textures,... 相似文献
923.
Ocean Science Journal - High-resolution geochemical measurements were performed on core E09-08, which was taken from the top flat area of the Korea Plateau in the East Sea (Japan Sea). Based on... 相似文献
924.
Ocean Science Journal - Surfgrass (Phyllospadix spp.) is a marine flowering plant that attaches to the bedrock of the Pacific Ocean, where the tide is fast and the waves are strong. In Korea, two... 相似文献
925.
Shin Chang-Woong Min Hong Sik Lee Seok Kang Hyoun-Woo Ku Bonhwa Kim Dong Guk Park Joonseong Kwon Soonyeol Choi Byoung-Ju 《Ocean Science Journal》2022,57(3):365-380
Ocean Science Journal - The seasonal and spatial variation of the current structure and volume transport across the Jeju Strait (JS) is described based on an analysis of the data from five bottom... 相似文献
926.
Haeyoung Lee Jeong Eun Kim Youngsin Chun 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(1):49-56
This study investigated meteorological, physical, and chemical characteristics of 2 severe Hwangsa (Asian dust, maximum average of PM10 above 1000 μg m?3) observed in Seoul, the capital city of Korea, during 30~31st May, 2008 (DSS2008) and 25~26th December, 2009 (DSS2009). DSS2008 and DSS2009 had a same source region and route. However, they have different meteorological conditions. DSS2009 had a shorter travel time from the source region to Korea and shorter duration time in Korea than DSS2008 due to a strong winter Siberian anticyclone. One of DSS2008 sample was affected by not only Asian dust but also a long-range transported haze due to consecutive influx after low pressure passed while DSS2009 sample collected only dust aerosol. For both cases, the mass concentration of coarse particles (PM10-1) increased by 3~14 times compared to that during non Asian dust period, however, that of fine particles (PM1) increased only in DSS2008. For DSS2008 water-soluble ion balance between anions and cations in fine mode was close to 1:1 while cations were higher than anions in coarse mode. NH4 + and Ca2+ were found to be the main contributing factors for the neutralization. Cl? loss was observed about 60% indicating an active interaction of Na+ with pollutants. Reconstruction of chemical compositions showed relatively high concentrations of secondary pollutants (NH4NO3 and (NH4)2SO4), CaCO3, and Ca(NO3)2 compared to that during non Asian dust period. DSS2009 exhibited the typical characteristics of Asian dust having a high concentration of Ca2+ with higher equivalent concentration of cations than anions in all size bins. Cl? loss was hardly observed. The secondary pollutants were lower than that of non Asian dust cases. The result of reconstruction of ionic components indicated the CaCO3 derived from soil particle, CaSO4, and Ca (NO3)2 were dominant in DSS2009. 相似文献
927.
Kwang-Yul Kim Ji-Won Kim Maeng-Ki Kim Chun-Ho Cho 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(5):675-685
Daily winter temperatures in Korea have been analyzed via CSEOF analysis. Then, each PC time series was detrended and was fitted to an AR (autoregressive) model. Based on the identified AR model, an artificial time series of arbitrary length can be generated by using an arbitrary white-noise time series. In this way, one hundred new sets of PC time series were generated over the period of 1973–2058. Then, the trend for each PC time series was added back to the artificial PC time series extending the trend until 2058. Ultimately, artificial daily winter temperatures in Korea have been constructed by using the artificial PC time series and the original loading vectors derived from the observational data. The 100 new data sets have been investigated in order to understand the winter temperature variability 50 years into the future. Regression analysis in CSEOF space shows that temperature increase in Korea is associated with increased 850-hPa air temperature over most of the Asian domain (97°-153°E × 22°-73°N) and increased 850-hPa geopotential height in the southern part of the domain. As a result, southerly and southeasterly wind anomalies develop carrying positive temperature anomalies northward and northwestward. Both the 200-hPa air temperature and geopotential height changes indicate that there will be fairly significant northward shift of the jet stream in future. The standard deviation of the 200-hPa potential vorticity increases implying that shortwave trough and henceforth baroclinic instability will increase in future. Finally, GEV (Generalized Extreme Value) distribution and GPD (Generalized Pareto distribution) distribution have been compared between the observational records and the future records of the same length. The extreme value distributions based on the synthetic datasets show that warm extreme events will be more extreme in future and cold extreme events, on the other hand, will be less extreme. This study provides an estimate of future temperatures based on the observational data and serves as an independent baseline solution for comparisons with numerical model solutions. 相似文献
928.
Chang H. Jung Junshik Um Ji Yi Lee Yong P. Kim 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(5):625-634
This study characterizes the Ångstrom exponent for polydispersed aerosol size distributions. Under the assumption of a lognormal size distribution, the dependence of Ångstrom exponent on the size distribution and the refractive index with varying real and imaginary parts are determined. Further, the influence of coarse mode particles on the Ångstrom exponent is investigated quantitatively. The results show that the nuclei mode has less influence under the simulation conditions considered in this study. It is also shown that the refractive index is an important factor influencing the Ångstrom exponent. The effect of the coarse mode on the Ångstrom exponent computed with different aerosol number concentrations and as a function of a geometric standard deviation and a geometric mean diameter is tested. It is shown that the coarse mode is crucial for determining the Ångstrom exponent. 相似文献
929.
In this research, we studied the effects of black carbon (BC) aerosol radiative forcing on seasonal variation in the Northern Hemisphere (NH) using numerical simulations with the NASA finite-volume General Circulation Model (fvGCM) forced with monthly varying three-dimensional aerosol distributions from the Goddard Ozone Chemistry Aerosol Radiation and Transport Model (GOCART). The results show that atmospheric warming due to black carbon aerosols subsequently warm the atmosphere and land surfaces, especially those over Eurasia. As a result, the snow depth in Eurasia was greatly reduced in late winter and spring, and the reduction in snow cover decreased the surface albedo. Our surface energy balance analysis shows that the surface warming due to aerosol absorption causes early snow melting and further increases surface-atmosphere warming through snow/ice albedo feedback. Therefore, BC aerosol forcing may be an important factor affecting the snow/ice albedo in the NH. 相似文献
930.