全文获取类型
收费全文 | 305篇 |
免费 | 56篇 |
国内免费 | 177篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 241篇 |
地球物理 | 82篇 |
地质学 | 117篇 |
海洋学 | 44篇 |
天文学 | 3篇 |
综合类 | 9篇 |
自然地理 | 40篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 24篇 |
2018年 | 11篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 21篇 |
2014年 | 14篇 |
2013年 | 29篇 |
2012年 | 16篇 |
2011年 | 25篇 |
2010年 | 14篇 |
2009年 | 20篇 |
2008年 | 15篇 |
2007年 | 34篇 |
2006年 | 24篇 |
2005年 | 10篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 14篇 |
2001年 | 17篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 27篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 15篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 17篇 |
排序方式: 共有538条查询结果,搜索用时 15 毫秒
141.
142.
The Analysis on the Features of the Atmospheric Circulation in Preceding Winters for the Summer Drought and Flooding in the Yangtze And Huaihe River Valley 总被引:12,自引:1,他引:12
TheAnalysisontheFeaturesoftheAtmosphericCirculationinPrecedingWintersfortheSummerDroughtandFloodingintheYangtzeandHuaiheRiver... 相似文献
143.
Evidence is presented of a periodic component in the inter-annual variability of precipitation and pressure data for India
during June, the month of the onset of the Indian southwest monsoon. Two frequencies that explain a statistically significant
percent of the variance in these data sets are the same as the two that explain most of the variance of the average monthly
lunar tidal potential for June. Not only are the frequencies the same but they are also in phase which strongly suggests that
lunar tides in the atmosphere do, in fact, produce an element of climatic variability. The amplitude of the atmospheric response
to this periodic forcing was not constant in time but was found to be related to the long term change in northern hemispheric
surface temperature. This susceptibility of the atmosphere to an external forcing results in a nonlinear relationship between
forcing and response. As a result, nonlinear regression had to be used in order to adequately define the magnitude of the
response at a given frequency. The ramifications of this nonlinear response are discussed. The nonlinear interaction of the
northern hemisphere temperature and the 18.6 year lunar nodal cycle results in a modulation of the frequency which appears
in a linear spectral analysis near 22 years. Thus, the 22-year cycle often found in meteorological data sets may instead be
the result of the modulated nodal cycle. 相似文献
144.
M. Kanamitsu 《Pure and Applied Geophysics》1977,115(5-6):1187-1208
The mechanisms of the maintenance of the tropical upper tropospheric quasi-stationary ultralong waves during the northern hemisphere summer season are briefly reviewed and discussed. Diagnostic and prognostic studies indicate that the waves are maintained by the land-ocean contrast heating. These scales of motion as a whole (sum of the zonal wavenumbers 1, 2 and 3) are considered to supply kinetic energy to all other scales of motion.The ultralong waves predicted in the real data numerical prediction experiment over the global tropics using a multi-level primitive equation model are examined and compared with the observed climatological waves. The predicted waves are found to have several similarities with the observations. Further investigations of the baroclinic nature of the waves indicate that their thermal structure is essential for understanding their dynamics.The vorticity budget computations are performed for the predicted ultralong waves at 200 mb and also compared with the climatological observations. It is found that the advection term is one of the leading terms in the vorticity equation.This study indicates that the tropical quasi-stationary ultralong waves are fully nonlinear, non-geostrophic, three-dimensional waves forced mainly by the convective heating over the monsoon Indian subcontient. 相似文献
145.
The paper deals with an application of a stochastic model to the frequency and duration of precipitation events. With the aid of the model, the magnitudes ofmth highest rainfall amount in 24 hours' duration with 97.5% probability are obtained for various climatic regimes over a tropical monsoon region. There is good agreement between them-day minimum rainfall estimated through the model and the observed value. The model satisfactorily explains the frequency of the extreme rainfall event. 相似文献
146.
147.
利用逐日Micaps 1°× 1°客观分析资料 ,合成分析了 2 0 0 2年 6月 6次大到暴雨过程的大尺度背景场 ,诊断分析了形成大到暴雨的水汽和动力条件。结果表明 :2 0 0 2年 6月的强降水主要由印度季风活动的影响产生 ,孟加拉湾是云南强降水的主要水汽源地 ,为其提供充沛的水汽条件 ,其水汽输送路径与云南降水落区关系密切 ,水汽通量辐合是云南产生强降水的必要条件 ,而川滇间的低涡切变是云南强降水的重要天气系统 ,提供了有利的背景条件及动力条件。 相似文献
148.
The nature and development of epikarst and soil development in aeolianites under a monsoonal climatic regime has not yet been described. Late Quaternary aeolianites of the southeastern coast of Saurashtra in western India show a wide array of epikarst and red-soil formation, and serve to typify the character of aeolianite weathering under a monsoonal climate. Three varieties of epikarst are identified that represent down-profile increase in groundwater flow. Five types of Terra Rossae represent a transition from the karstified limestone to soil development. Terra Rossae differ in the content of residual aeolianite and show both simple and complex profiles. The latter at places shows ped development. The results show that an ontogenetic (growth) sequence exists from incipient epikarst to complex palaeosols. This ontogenetic sequence represents an incremental increase in the groundwater budget of the region in response to changing intensification of the Indian monsoon rainfall. Magnetic properties of the Terra Rossae formed under a monsoonal climate are described for the first time. The magnetic susceptibility together with its frequency-dependent and anhysteretic remanent magnetization (ARM) represents both the concentration of single domain and ultrafine superparamagnetic (SP) magnetite. The formation of single domain and superparamagnetic magnetite and hematite are linked genetically to weathering of the aeolianite that leads to the formation of Terra Rossa. 相似文献
149.
The δ18O variations in an 80.36 m ice core retrieved in the accumulation zone of the East Rongbuk Glacier, Mount Qomolangma (Everest), is not consistent with changes of air temperature from both southern and northern slopes of Himalayas, as well as these of the temperature anomalies over the Northern Hemisphere. The negative relationship between the δ18O and the net accumulation records of the ice core suggests the "amount effect" of summer precipitation on the δ18O values in the region. Therefore, the δ18O records of the East Rongbuk ice core should be a proxy of Indian Summer Monsoon intensity, which shows lower δ18O values during strong monsoon phases and higher values during weak phases. 相似文献
150.
利用NCEP/NCAR月平均风场和比湿资料分析了亚洲季风区平均水汽输送通量的气候特征和季节变化;研究了山东旱涝年季风区水汽输送的差异及其在不同时段对山东夏季降水异常的贡献。结果表明,山东地区的平均水平水汽输送通量存在着明显的年际变化,纬向、经向和总水汽输送通量随时间均呈单峰曲线分布,7月达极值;影响山东夏季降水的印度季风区水汽输送以纬向为主、副热带季风区水汽输送以经向为主;5~6月,来自热带印度洋的西南季风水汽输送通量、西太平洋热带和副热带东南季风水汽输送通量以及南海北部的水汽输送通量对山东夏季降水均有贡献,涝年水汽输送通量明显大于旱年。虽然7月来自印度洋的西南季风水汽输送通量达极值,但对山东夏季降水异常的贡献并不显著,7~8月主要是来自西太平洋地区的热带和副热带季风水汽输送对山东夏季降水异常的贡献较明显。 相似文献