全文获取类型
收费全文 | 668篇 |
免费 | 284篇 |
国内免费 | 684篇 |
专业分类
测绘学 | 23篇 |
大气科学 | 1000篇 |
地球物理 | 45篇 |
地质学 | 44篇 |
海洋学 | 439篇 |
综合类 | 38篇 |
自然地理 | 47篇 |
出版年
2024年 | 7篇 |
2023年 | 31篇 |
2022年 | 65篇 |
2021年 | 68篇 |
2020年 | 97篇 |
2019年 | 99篇 |
2018年 | 48篇 |
2017年 | 56篇 |
2016年 | 33篇 |
2015年 | 60篇 |
2014年 | 74篇 |
2013年 | 76篇 |
2012年 | 76篇 |
2011年 | 78篇 |
2010年 | 59篇 |
2009年 | 87篇 |
2008年 | 65篇 |
2007年 | 88篇 |
2006年 | 73篇 |
2005年 | 54篇 |
2004年 | 51篇 |
2003年 | 47篇 |
2002年 | 33篇 |
2001年 | 34篇 |
2000年 | 13篇 |
1999年 | 22篇 |
1998年 | 26篇 |
1997年 | 25篇 |
1996年 | 22篇 |
1995年 | 27篇 |
1994年 | 19篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1989年 | 2篇 |
排序方式: 共有1636条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
THE STUDY OF STORM RAINFALL CAUSED BY INTERACTION BETWEEN THE NON-ZONAL HIGH LEVEL JET STREAK AND TYPHOON IN THE DISTANCE 总被引:1,自引:1,他引:1
In this paper, statistics were analyzed concerning correlation between the storm rainfall far from
typhoon and non-zonal upper-level jet stream. The results show that the jet stream at 200 hPa is constantly SW
(90.2 %) during the period in which storm rainfall occurs. Rainfall area lies in the right rear regions of the jet
axes. While the storm intensifies, the jet tends to be stronger and turn non-zonal. With the MM4 model, numerical
simulation and diagnosis were carried out for Typhoon No.9711 (Winnie) on August 19 to 20, 1997.
The distant storm rainfall is tightly correlative to the jet and low-level typhoon trough. The divergence field of
jet is related to the v component. The upper level can cause the allobaric wind convergence at low level. This is
the result of the form of low-level typhoon trough and the strength of the storm. By scale analysis, it is found
that there is a branch of middle scale transverse inverse circulation in the right entrance regions behind the jet
below the 300-hPa level, which is very important to the maintenance and strengthening of storm rainfall. This
branch of inverse circulation is relative to the reinforcement of jet's non-zonal characteristics. From the field of mesoscale divergence field and non-zonal wind field, we know that the stronger symmetry caused by transverse
circulation in the two sides of the jet, rainfall’s feedback and reinforcement of jet’s non-zonal characteristics
had lead to positive feedback mechanism that was favorable of storm rainfall’s strengthening. 相似文献
75.
该文首先采用合成分析的方法研究了江淮入梅前后大尺度大气环流的演变特征和西太平洋副热带高压西伸北跳的可能机制。研究结果表明, 江淮入梅前期的最显著的特征是:副热带高压首先在太平洋中部增强北跳, 而后向西扩展导致太平洋副高西部脊 (120°E) 的增强北跳。进一步分析表明, 在太平洋中部副热带高压的增强北跳和西伸之前, 副热带高压南侧ITCZ中对流和孟加拉湾北部的对流活动明显并且都经历了一次增强活跃过程, 这意味着热带ITCZ和孟加拉湾北部对流的异常活跃可能对副热带高压的增强北跳西伸产生影响。全球大气环流模式模拟结果表明, 赤道中太平洋ITCZ中对流异常活跃不仅可导致副热带高压的增强北移, 而且还可导致副热带高压西伸, 与诊断分析结果相一致。 相似文献
76.
Large tectonic movement of the Japan Arc in late Cenozoic times inferred from paleomagnetism: Review and synthesis 总被引:4,自引:0,他引:4
Abstract Paleomagnetic studies facilitate an understanding of the evolution of the Japan Arc in Cenozoic times from the perspective of tectonic movement. The Japan Arc rifted from the Asian continent in the middle Miocene, while East Asia, including the Japan Arc, moved northward at the same time. The rifting phenomenon of the Japan Arc is described by differential rotation of Southwest and Northeast Japan. Southwest Japan was rotated clockwise through about 45° and Northeast Japan was rotated counter-clockwise through about 40°. This differential rotation occurred concurrently at about 15 Ma. Eighty percent of the rotation was completed during a period of 1.8 million years. These factors lead us to propose a'double door'opening mode with a fast spreading rate of 21 cm/yr for the evolution of the Japan Sea, suggesting that the asthenosphere with a low viscosity was injected beneath the Japan Sea area. The large northward motion of East Asia in relation to Europe is expected from the apparent polar wander path constructed from the paleomagnetic data of the Japan Arc. East Asia may have moved northward by more than 1700 km between 20 Ma and 10 Ma accompanied by a slightly clockwise rotation of 10°. The eastern part of the Eurasian plate was subjected to extreme geodynamic conditions in late Cenozoic times. 相似文献
77.
非常定自适应网格模式在台风路径数值预报中的应用 总被引:7,自引:0,他引:7
本文将作者在前文中介绍的非常定自适应网格模式用于台风路径的数值预报。由于自适应网格在台风中心附近安排了较密的网格,有效地提高了网格的分辨率,使得台风环流的结构在预报48小时以后仍能保持,其预报的路径与实况相比令人鼓舞。 相似文献
78.
79.
Wang Pengyun 《Acta Meteorologica Sinica》1999,13(4):474-493
The track,landfall,dynamic and thermodynamic and cloud-rain physical mesoscale structures and their evolution of typhoon HERB 1996 in 36 h from 0000 UTC 31 July to 1200 UTC 1 August 1996 were simulated by using the non-hydrostatic mesoscale model MM5.This period covered the process of typhoon HERB landfall at Taiwan and Fujian Provinces.Results show that the model successfully simulated the landfall process of typhoon HERB,revealed the most important characteristics of the mesoscale dynamic and thermodynamic and cloud-rain physical structure during its landfall.The simulated typhoon track was close to the observation.The center of cyclonic circulation simulated at 0000 UTC on 1 August 1996 (24 h integration) was located in shore near Fuqing,Fujian Province at which the typhoon was reported to landfall two hours later.It shows that strong upward motion formed by low level convergence existed in the eye-wall and subsidence at the eye.The wind field shows clear asymmetrical structure near the typhoon center.The cloud and rainband was screw-typed distributed around typhoon center,and consisted of meso-β scale rain cores.During the period of typhoon HERB staying near and passing over Taiwan,the lower cloud was developed in the eye region so that the previous clear typhoon eye on the satellite pictures became fuzzy.Observation shows that the typhoon center was "warm",but the model simulations with higher space resolution show that in the mid-troposphere the region of eye-wall with stronger upward motion and more cloud-and rain-water was warmer than the eye.During the period of typhoon passing over Taiwan and its following landfall at Fujian,the track of model typhoon deviated about 30 km northward (i.e.,rightward) because of the orographic effects of Taiwan Island,but the strength of the typhoon was not affected remarkably.The amount of rainfall on Taiwan in the 36 h simulations was enhanced more than six times by the orographic lifting of Taiwan Mountain. 相似文献
80.
Statistic and typical-year composition methods are used to study the northwest Pacific typhoon activities in relation with the EI Niño and La Niña events. The result indicates that the typhoon tends to be inactive in the EI Niño years and active in the La Niña years and it is also dependent on the onset and ending time and intensity of the events and areas of genesis of typhoons. With statistic features of the frequency of typhoon activity in the EI Niño and La Niña years and the time-lag correlation between the frequency and sea surface temperature(SST), useful information is provided for the prediction of typhoon occurrence. In addition, the singular values disassemble(SVD)method is applied to study the correlation between the geopotential field and SST field. The result shows that the air-sea coupling in the EI Niño years is unfavorable for the typhoon to develop. Which take place with a smaller number. Opposite situations are found with the La Niña years. 相似文献