全文获取类型
收费全文 | 337篇 |
免费 | 51篇 |
国内免费 | 66篇 |
专业分类
测绘学 | 7篇 |
大气科学 | 1篇 |
地球物理 | 51篇 |
地质学 | 333篇 |
海洋学 | 14篇 |
天文学 | 1篇 |
综合类 | 17篇 |
自然地理 | 30篇 |
出版年
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 14篇 |
2013年 | 25篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 19篇 |
2009年 | 23篇 |
2008年 | 28篇 |
2007年 | 19篇 |
2006年 | 21篇 |
2005年 | 11篇 |
2004年 | 22篇 |
2003年 | 22篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 19篇 |
1998年 | 14篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有454条查询结果,搜索用时 296 毫秒
101.
102.
103.
Rob Inkpen 《地球表面变化过程与地形》1995,20(9):783-793
Portland Stone and Monks Park limestone tablets were used to assess weathering loss over a two-year study. Procedures involved in preparing tablets for exposure, attaching them to the exposure frame and reweighing might have influenced weight changes measured. The impact of each stage in the above procedures was tested to assess how much weight loss was generated and how significant the loss was comparing the two stone types and the final loss sustained upon weathering. Although all the procedures seem to produce a statistically insignificant amount of weight loss, the two stone types do respond differently to the procedures. This suggests that stone properties may be important in determining the accuracy with which tablets can be used to assess spatial patterns of weathering. 相似文献
104.
105.
肖骐 《华东地质学院学报》1995,18(1):29-32
湖南出产宝石历史悠久,长期以来远销海内外,菊花石工艺享誉全球,曾多次在国际博览会上获奖。还有较丰富的海蓝宝石、祖母绿、水晶等十几种宝石、玉石、彩石资源。其地质成因类型主要有砂矿型、沉积型、伟昌岩型、火山岩型,气成-热液型、沉积变质和接触变质型。 相似文献
106.
介绍了黄金珠宝首饰的一些基本观念和近年来黄金珠宝市场的发展状况,指出1994年纯金饰品消费将会稳定增长,而且仍占主流,珠宝首饰市场会出现消费量增长,竞争日渐激烈,并由大中城市向中小城市扩展的趋势。就四川宝玉石普查找矿和开发利用提出了见解。 相似文献
107.
108.
B. J. Smith J. A. Baptista-Neto M. A. M. Silva J. J. McAlister P. A. Warke J. M. Curran 《Environmental Geology》2004,46(3-4):493-503
The 500th anniversary of European arrival in Brazil was celebrated in 2000 and highlighted the need to review the condition of the countrys remaining colonial built heritage. This revision is particularly apposite in the adjacent cities of Rio de Janeiro and Niterói, where the heritage that survived twentieth century reconstruction has done so largely because of ownership by the church or military. However, whilst this may have protected buildings from demolition, detailed fabric can be neglected or abused. This paper investigates this possibility through an examination of two forts, built primarily of local augen gneiss, that guard the entrance to Guanabara Bay. Natural outcrops exposed to the same humid sub-tropical maritime environment show that this rock is susceptible to slow disaggregation through salt weathering. Surveys suggest that stonework in the forts that is sheltered from rainwash is heavily loaded with salt and has passed a threshold, wherein stresses accumulated over centuries of apparent stability, combined with the effects of a more recent increase in atmospheric pollution and apparently inappropriate intervention (re-pointing), have triggered rapid breakdown that requires immediate intervention. 相似文献
109.
110.
The survival of several ancient monuments made of ignimbrites in Hınıs town (Erzurum-Anatolia), which has suffered from intense annual temperature fluctuations and strong seismic activity, can mainly be attributed to use of suitable building stones. This paper examines the usability as building stones of Middle Miocene Hınıs ignimbrites that widely outcrop in and around Hınıs town. The petrographical, geochemical, mechanical, and physical properties determined lead to categorization of the ignimbrites as four different types. The Hınıs ignimbrites contain dasite–trachy–andesite and rhyolite. Rhyolite is the strongest material whereas the other types, being more porous, are weaker, lighter, and have good heat-insulation properties. Being light (easily transportable, machinable, and workable), good heat insulators, environmentally friendly (because of natural ventilation), sufficiently elastic to sustain seismic loading in the area under study, and more cost-effective than artificial stones, Hınıs ignimbrites are certainly a preferable option for use as light building stone. These ignimbrites are not suitable for use as floor covering, however, (because of rapid abrasion) or for building structural columns (because of low strength). 相似文献