全文获取类型
收费全文 | 1749篇 |
免费 | 325篇 |
国内免费 | 188篇 |
专业分类
测绘学 | 38篇 |
大气科学 | 123篇 |
地球物理 | 836篇 |
地质学 | 621篇 |
海洋学 | 235篇 |
天文学 | 17篇 |
综合类 | 62篇 |
自然地理 | 330篇 |
出版年
2023年 | 10篇 |
2022年 | 51篇 |
2021年 | 64篇 |
2020年 | 70篇 |
2019年 | 60篇 |
2018年 | 54篇 |
2017年 | 70篇 |
2016年 | 66篇 |
2015年 | 64篇 |
2014年 | 71篇 |
2013年 | 78篇 |
2012年 | 70篇 |
2011年 | 98篇 |
2010年 | 77篇 |
2009年 | 106篇 |
2008年 | 141篇 |
2007年 | 130篇 |
2006年 | 120篇 |
2005年 | 107篇 |
2004年 | 89篇 |
2003年 | 64篇 |
2002年 | 60篇 |
2001年 | 62篇 |
2000年 | 47篇 |
1999年 | 44篇 |
1998年 | 64篇 |
1997年 | 42篇 |
1996年 | 47篇 |
1995年 | 47篇 |
1994年 | 26篇 |
1993年 | 29篇 |
1992年 | 26篇 |
1991年 | 19篇 |
1990年 | 34篇 |
1989年 | 20篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有2262条查询结果,搜索用时 390 毫秒
61.
62.
Introduction Estimation of an attenuation relationship for strong ground motion parameters has been an interesting research subject in the field of engineering seismology and has played a very important role in seismic safety evaluation, seismic zoning, seismic hazard evaluation of major constructions, etc. At present, the generally used parameters include peak acceleration, peak velocity and elastic response spectrum. Such parameters mentioned above are essentially independent of the duration… 相似文献
63.
Jiang Jiayu Fu Shouxian Li Jiuling 《应用地球物理》2005,2(4):241-246
Branching river channels and the coexistence of valleys, ridges, hiils, and slopes'as the result of long-term weathering and erosion form the unique loess topography. The Changqing Geophysical Company, working in these complex conditions, has established a suite of technologies for high-fidelity processing and fine interpretation of seismic data. This article introduces the processes involved in the data processing and interpretation and illustrates the results. 相似文献
64.
Liu Xiqiang 《中国地震研究》2005,19(3):269-281
INTRODUCTIONThe structural mine earthquake in coal mines refers to the quake induced by excavationengineeringthatleadstorupturingor change of geological structure and weakness surfaceintheinteriorof rock mass.According to the origin,mine earthquakes can b… 相似文献
65.
本文以长沙市中医医院的方案设计为例,对如何利用自然环境划分、组织建筑空间以及结合当地人文、地理环境塑造合理的建筑造型进行了详尽的描述。 相似文献
66.
67.
A granitic rock avalanche, one of the largest Quaternary landslides in Arizona outside the Grand Canyon with a volume of approximately 5.25 M m3 and a width a little under 0.5 km, ran 1 km from the eastern McDowell Mountains. With lateral levees and pressure ridges, the rock avalanche deposit displays many features found on classic sturzstroms. Failure occurred along a major joint plane paralleling the slope with a dip of 44°, when a major base level lowering event in the Salt River system would have undermined the base of the failed slope, and probably during a period of more moisture than normally available in the present-day arid climate. Failure at the subsurface weathering front highlights the importance of the dramatic permeability change between grussified regolith and relatively fresh bedrock. Rock varnish microlaminations (VMLs) dating, in concert with other geomorphic evidence, suggests that the rock avalanche deposit is slightly older than 500 ka. The rock vanish results also have important implications for sampling strategies designed to use cosmogenic nuclide to date Quaternary landslide deposits. Discovery of a large landslide in close proximity to the extending urban fringe of metropolitan Phoenix argues for a more careful analysis of landslide hazards in the region, especially where rapid development excavates bedrock at the base of steep mountain slopes and where the subsurface weathering front is near the surface. 相似文献
68.
69.
70.
The organic matter of the surface horizons of soils developed below scrub vegetation in a Mediterranean semi-arid area of great environmental interest (Cabo de Gata-Níjar Natural Park, SE Spain) has been studied. The study mainly concentrates on examining the influence of two vegetation types, one evolved (according to its successional stage), and the other clearly degraded as a result of prior removal of vegetation. In spite of the homogeneity in the results obtained from the analysis of the organic matter from the soils studied, a relationship may be established between vegetation biotype and characteristics and evolution of the soil organic matter. The evolved vegetation results in the presence in the soil of a somewhat more evolved and stable organic matter (demonstrated by certain chemical and microbiological aspects), resulting in a greater degree of humification, thus favouring the protection of the soil and the ecosystem as a whole. Hence, the presence of degraded vegetation might lead to soil degradation, something that is unsustainable in semi-arid areas that are particularly fragile in nature. 相似文献