全文获取类型
收费全文 | 1577篇 |
免费 | 590篇 |
国内免费 | 304篇 |
专业分类
测绘学 | 181篇 |
大气科学 | 110篇 |
地球物理 | 321篇 |
地质学 | 1207篇 |
海洋学 | 175篇 |
天文学 | 46篇 |
综合类 | 99篇 |
自然地理 | 332篇 |
出版年
2024年 | 6篇 |
2023年 | 12篇 |
2022年 | 39篇 |
2021年 | 95篇 |
2020年 | 78篇 |
2019年 | 82篇 |
2018年 | 75篇 |
2017年 | 72篇 |
2016年 | 85篇 |
2015年 | 97篇 |
2014年 | 112篇 |
2013年 | 141篇 |
2012年 | 118篇 |
2011年 | 105篇 |
2010年 | 80篇 |
2009年 | 108篇 |
2008年 | 107篇 |
2007年 | 112篇 |
2006年 | 108篇 |
2005年 | 109篇 |
2004年 | 86篇 |
2003年 | 80篇 |
2002年 | 91篇 |
2001年 | 69篇 |
2000年 | 55篇 |
1999年 | 51篇 |
1998年 | 55篇 |
1997年 | 38篇 |
1996年 | 35篇 |
1995年 | 32篇 |
1994年 | 27篇 |
1993年 | 22篇 |
1992年 | 26篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有2471条查询结果,搜索用时 154 毫秒
61.
62.
LIU Shiyin WANG Ninglian DUAN Keqin XIAO Cunde DING Yongjian HAN Haidong 《地理学报(英文版)》2004,14(4):401-410
1IntroductionIn the early 1960s, glaciers in western China were classified into maritime- and continental-types by different glacial environment and physical characteristics (Shi and Xie, 1964). With extensive glaciological investigations in the western regions (Lanzhou Institute of Glaciology and Geocryology of CAS, 1988), Lai and Huang (1990) suggested a new classification of temperate, subpolar and quasipolar glaciers, corresponding to the maritime-, subcontinental- and extremely contin… 相似文献
63.
64.
Glacier inventory compilation during the past 20 years and modifications of that for the Eastern Pamir and Banggong Lake indicate that there are 46,342 modern glaciers with a total area and volume of 59415 km2 and 5601 km3 respectively in China. These glaciers can be classified into maritime and continental (including sub-continental and extremely continental) types. Researches show that glaciers in China have been retreating since the Little Ice Age and the mass wastage was accelerated during the past 30 to 40 years. Being an important part of glaciological studies in China, ice core climatic and environmental studies on Tibetan Plateau and in the Antarctica have provided abundant, high resolution information about past climatic and environmental evolution over the Tibetan Plateau and Antarctica. Except for different parameters recorded in ice cores relating to climate and environment changes on Tibetan Plateau, records from ice cores extracted from different glaciers show that the discrepancies in climatic and environmental changes on the north and south parts of the plateau may be the consequence of different influencing effects from terrestrial and solar sources. Glaciological and meteorological phenomena imply that Lambert Glacier valley is an important boundary of climate in the east Antarctica, which is thought to be connected with cyclonic activities and Circum-polar Waves over the Antarctica. 相似文献
65.
66.
67.
68.
Significant faulting and deformation of the ground surface has been rarely known during volcanic eruptions. Usu Volcano, Hokkaido, Japan, is a unique example of deformation due to felsic magma intrusion. Usu Volcano has a history of such types of eruptions as phreatic, pumice eruption (Plinian type), pyroclastic flowing and lava doming since 1663. On March 31, 2000, phreatomagmatic to phreatic eruptions took place after 23 years of dormancy in the western piedmont, followed by explosions on the western flank of Usu Volcano. They were associated with significant deformation including faulting and uplift. The eruptions and deformation were continuing up to the end of May 2000.We identified the faulting using total nine sets of aerial photographs taken from before the eruption (March 31, 2000) to more than 1 year (April 27, 2001) after the end of the activity, and traced deformation processes through image processing using aerial photographs. We found that some of the new faults and the associated phreatic eruptions were related to old faults formed during the 1977–1981 eruptive episode.The image processing has revealed that the surface deformation is coincident with the area of faulting forming small grabens and the phreatic explosion vents. However, the faulting and main explosive eruptions did not take place in the highest uplift area, but along the margin. This suggests that the faulting and explosive activities were affected by small feeder channels diverging from the main magma body which caused the highest uplift. 相似文献
69.
M. Malinowski 《Studia Geophysica et Geodaetica》2005,49(4):485-500
The aim of this paper is to show the application of short-period surface waves recorded during deep seismic sounding experiment
for constraining shallow velocity structure of the crust. Phase velocity of fundamental mode Rayleigh waves, observed along
the CELEBRATION 2000 experiment profile CEL09, were obtained by a p-ω method and has been subsequently inverted for one-dimensional
shear velocity models for the top 2 km. Multiple filter technique applied to one shot gather was used to carry out a joint
inversion of phase and group velocity data and to provide γR data to be used for Qβ inversion. Validity of obtained VS and Qβ models was confirmed by the reflectivity method. Noticeably, no clear dispersive wawes were observed in the Tepla-Barrandian
Unit. Quasi-2D model based on the individual 1D VS models is well correlated with the surface geology. Lower VS are observed in the Saxothuringian Zone in comparison to the Moldanubian Zone. In the vicinity of the Central Bohemian and
Moldanubian Plutons, the near-surface VS values are relatively low, but below 1 km depth, they are higher than in surrounding areas. We interpret it as the result
of the weathering and cracks within the granitoid rocks. 相似文献
70.
Pollen collected from snow samples on the Quelccaya Ice Cap in 2000 and 2001 reveals significant interannual variability in pollen assemblage, concentration, and provenance. Samples from 2000, a La Niña year, contain high pollen concentrations and resemble samples from the Andean forests (Yungas) to the east. Samples from 2001, an El Niño year, contain fewer pollen and resemble those from the Altiplano. We suggest that varying wind patterns under different El Niño/Southern Oscillation (ENSO) conditions may affect the processes of pollen transport over the Altiplano and on the ice cap, although confounding variables such as flowering phenology and sublimation should also be considered 相似文献