全文获取类型
收费全文 | 4598篇 |
免费 | 755篇 |
国内免费 | 944篇 |
专业分类
测绘学 | 306篇 |
大气科学 | 731篇 |
地球物理 | 1096篇 |
地质学 | 2284篇 |
海洋学 | 540篇 |
天文学 | 193篇 |
综合类 | 505篇 |
自然地理 | 642篇 |
出版年
2024年 | 11篇 |
2023年 | 70篇 |
2022年 | 190篇 |
2021年 | 265篇 |
2020年 | 188篇 |
2019年 | 195篇 |
2018年 | 228篇 |
2017年 | 224篇 |
2016年 | 261篇 |
2015年 | 233篇 |
2014年 | 287篇 |
2013年 | 274篇 |
2012年 | 269篇 |
2011年 | 298篇 |
2010年 | 319篇 |
2009年 | 266篇 |
2008年 | 258篇 |
2007年 | 263篇 |
2006年 | 215篇 |
2005年 | 159篇 |
2004年 | 136篇 |
2003年 | 112篇 |
2002年 | 117篇 |
2001年 | 104篇 |
2000年 | 116篇 |
1999年 | 178篇 |
1998年 | 144篇 |
1997年 | 157篇 |
1996年 | 109篇 |
1995年 | 127篇 |
1994年 | 86篇 |
1993年 | 84篇 |
1992年 | 83篇 |
1991年 | 63篇 |
1990年 | 38篇 |
1989年 | 30篇 |
1988年 | 37篇 |
1987年 | 28篇 |
1986年 | 26篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1958年 | 4篇 |
排序方式: 共有6297条查询结果,搜索用时 521 毫秒
961.
Fredolin T. Tangang Changsui Xia Fangli Qiao Liew Juneng Feng Shan 《Ocean Dynamics》2011,61(9):1317-1328
A wave–tide–circulation coupled model based on Princeton Ocean Model is established to study the seasonal circulation in the
Malay Peninsula Eastern Continental Shelf region. The model successfully reconstructs the observed seasonal variation of the
circulation in the region, as well as the main currents. The simulated tidal harmonic constants, sea surface temperature,
and sea surface height anomaly agree with the observations well. The model results show that the upper-layer circulation in
the region is mainly controlled by the monsoon winds, while there are two transitions in spring and fall. An anti-cyclonic
eddy is present off the Peninsular Malaysia’s east coast in summer, centered at 5°N and 105.5°E, both in the TOPEX/Poseidon
data and in the model. Numerical experiments show that the wind stress curl and bathymetry steering are responsible for its
formation. 相似文献
962.
963.
964.
965.
966.
967.
The Wenchuan Earthquake (May 12, 2008), Sichuan Province,China, and resulting geohazards 总被引:19,自引:5,他引:14
Peng Cui Xiao-Qing Chen Ying-Yan Zhu Feng-Huan Su Fang-Qiang Wei Yong-Shun Han Hong-Jiang Liu Jian-Qi Zhuang 《Natural Hazards》2011,56(1):19-36
On Monday, May 12, 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenchuan area, northwestern Sichuan Province,
China. The focal mechanism of the earthquake was successive massive rock fracturing 15 km in depth at Yingxiu. Seismic analysis
confirms that the major shock occurred on the Beichuan–Yingxiu Fault and that aftershocks rapidly extended in a straight northeast–southeast
direction along the Longmenshan Fault zone. Fatalities approaching a total of 15,000 occurred, with a significant number resulting
from four types of seismically triggered geohazards—rock avalanches and landslides, landslide-dammed lakes (“earthquake lakes”),
and debris flows. China Geological Survey has identified 4,970 potentially risky sites, 1,701 landslides, 1,844 rock avalanches,
515 debris flows, and 1,093 unstable slopes. Rock avalanches and landslides caused many fatalities directly and disrupted
the transportation system, extensively disrupting rescue efforts and thereby causing additional fatalities. Landslide-dammed
lakes not only flooded human habitats in upstream areas but also posed threats to potentially inundated downstream areas with
large populations. Debris flows become the most remarkable geohazards featured by increasing number, high frequency, and low
triggering rainfall. Earthquake-triggered geohazards sequentially induced and transformed to additional hazards. For example,
debris flows occurred on rock avalanches and landslides, followed by landslide-dammed lakes, and then by additional debris
flows and breakouts of the landslide-dammed lakes and downstream flooding. Earthquake-induced geohazards occurred mainly along
the fault zone and decreased sharply with distance from the fault. It can be anticipated that post-earthquake geohazards,
particularly for debris flows, will continue for 5–10 years and even for as long as 20 years. An integrated strategy of continuing
emergency response and economic reconstruction is required. The lesson from Wenchuan Earthquake is that the resulted geohazards
may appear in large number in active fault regions. A plan for geohazard prevention in the earthquake-active mountainous areas
is needed in advance. 相似文献
968.
LIU Cui DENG Jinfu KONG Weiqiong XU Liquan ZHAO Guochun LUO Zhaohu LI Ning 《《地质学报》英文版》2011,85(5):1057-1066
The Wurinitu molybdenum deposit, located in Honggor, Sonid Left Banner of Inner Mongolia, China, is recently discovered and is considered to be associated with a concealed fine-grained granite impregnated with molybdenite.?The wall rocks are composed of Variscan porphyritic-like biotite granite and the Lower Ordovician Wubin’aobao Formation.?LA-ICP-MS zircon U-Pb dating of the fine-grained granite reveals two stages of zircons,?one were formed at 181.7±7.?4 Ma and?the other at 133.6±3.3 Ma. The latter age is believed to be the formation age of the fine-grained granite, while the former may reflect the age of inherited zircons, based on the morphological study of the zircon and regional geological setting. The Re-Os model age of molybdenite is 142.2±2.5?Ma, which is older than the diagenetic age of the fine-grained granite.?Therefore the authors believe that the metallogenic age of the Wurinitu molybdenum deposit should be?nearly 133.6±3.3 Ma or slightly later, i.e., Early Cretaceous.?Combined with regional geological background research, it is speculated that the molybdenum deposits were formed at the late Yanshanian orogenic cycle in the Hingganling-Mongolian orogenic belt, belonging to the relaxation epoch posterior to the compression and was associated with the closure of the Mongolia-Okhotsk?Sea. 相似文献
969.
970.