全文获取类型
收费全文 | 1179篇 |
免费 | 378篇 |
国内免费 | 1013篇 |
专业分类
测绘学 | 28篇 |
大气科学 | 76篇 |
地球物理 | 564篇 |
地质学 | 1702篇 |
海洋学 | 31篇 |
天文学 | 20篇 |
综合类 | 144篇 |
自然地理 | 5篇 |
出版年
2023年 | 2篇 |
2021年 | 2篇 |
2019年 | 2篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 86篇 |
2010年 | 39篇 |
2009年 | 101篇 |
2008年 | 34篇 |
2007年 | 95篇 |
2006年 | 181篇 |
2005年 | 203篇 |
2004年 | 252篇 |
2003年 | 240篇 |
2002年 | 182篇 |
2001年 | 156篇 |
2000年 | 106篇 |
1999年 | 72篇 |
1998年 | 117篇 |
1997年 | 102篇 |
1996年 | 62篇 |
1995年 | 45篇 |
1994年 | 35篇 |
1993年 | 122篇 |
1992年 | 105篇 |
1991年 | 30篇 |
1990年 | 16篇 |
1989年 | 22篇 |
1988年 | 5篇 |
1987年 | 19篇 |
1986年 | 11篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1950年 | 10篇 |
1944年 | 2篇 |
1943年 | 6篇 |
1942年 | 1篇 |
1940年 | 8篇 |
1937年 | 12篇 |
1934年 | 9篇 |
1933年 | 11篇 |
1928年 | 7篇 |
1927年 | 6篇 |
1926年 | 2篇 |
1924年 | 5篇 |
排序方式: 共有2570条查询结果,搜索用时 265 毫秒
991.
992.
Bioreactor landfill 总被引:2,自引:0,他引:2
WANGHao XINGKai AnthonyAdzomani 《东北亚地学研究》2004,7(1):85-91
Following the population expansion, there is a growing threat brought by municipal solid waste (MSW) against environment and human health. Sanitary landfill is the most important method of MSW disposal in China. In contrast to the conventional landfill, this paper introduces a new technique named bioreactor landfill (BL). Mechanisms, operation conditions as well as the advantages and disadvantages of BL are also discussed in this paper. 相似文献
993.
青藏高原中段晚喜马拉雅期地壳综短量分析 总被引:2,自引:2,他引:2
通过共/轭剪切角变化及其与地壳缩短量的函数关系,计算了青藏高原中段晚喜马拉雅期地壳构造变形量。结果表明,晚喜马拉雅期青藏高原中段地壳在近南北方向发生了巨量缩短,平均缩短量达30%;在近东西方向发生了巨量伸长,平均伸长量约74%。青藏高原中段晚喜马拉雅期地壳应变量尚表现出明显的分区性与自北向南逐步减少的变化趋势。 相似文献
994.
YUAN Zhongxin BAI Ge Institute of Mineral Deposits Chinese Academy of Geological Sciences Baiwanzhuang Rd. Beijing ZHANG Zongqing Institute of Geology Chinese Academy of Geological Sciences Baiwanzhuang Rd. Beijing 《《地质学报》英文版》2000,74(2):148-153
Trachytic rock and its altered rock-fenite-in the Bayan Obo ore district, Inner Mongolia, China, were referred to as slate or feldspar rock before, and identified by the authors for the first time (in 1992). In the paper the mineral assemblages, structures and textures and petrochemical compositions of the rocks, as well as the electron microprobe analysis of feldspars in the rocks are described. The Sm-Nd isochron age of the trachytic rock is 1096±56 Ma, with INd=0.51100+4 (2σ) and εNd(t)= -4.4±0.7. Alterations of the trachytic rock, including microclinization, riebeckitization, aegirinization and biotitization, and accompanied rare element and REE mineralizations are discussed. Based on the occurrence of the trachytic rock and associated fenitization it is deduced that the Bayan Obo Fe-Nb-REE ore deposit is genetically related to magmatic-hydrothermal activity of an alkali carbonatite complex. 相似文献
995.
Fluids and Melts in the Upper Mantle 总被引:3,自引:0,他引:3
XIA Linqi XIA Zuchun XU XueyiXi''an Institute of Geology Mineral Resources Chinese Academy of Geological Sciences East Youyi Rd. Xi ''an Zhu Xiling 《《地质学报》英文版》1999,73(3):330-340
This paper presents a direct study of the fluids and melts in the upper mantle by examining the fluid inclusions, melt inclusions and glasses trapped in the mantle lherzolite xenoliths entrained by Cenozoic alkali basalts (basanite, olivine-nephelinite and alkali-olivine basalt) from eastern China. The study indicates that the volatile components, which are dissolved in high-pressure solid mineral phases of mantle peridotite at depths, may be exsolved under decompressive conditions of mantle plume upwelling to produce the initial free fluid phases in the upper mantle. The free fluid phases migrating in the upper mantle may result in lowering of the mantle solidus (and liquidus), thereby initiating partial melting of the upper mantle, and in the meantime, producing metasomatic effects on the latter. 相似文献
996.
北京十三陵中元古代串岭沟期地质事的探索 总被引:4,自引:0,他引:4
宏观、微观和地球化学研究结果证明在北京十三陵中元古界长城系串沟组有地质事件层。宏观标志包括一系列地震滑塌、砂体液化、层内错断和角砾化构造等;微观标志包括火山晶屑,火山玻璃的假象,显微层内错位等。地球化学资料表明,Re、0s及其同位素和Ir含量异常,某些稀有元素含量的对比等等,都有可能说明地质事件引起了异常现象的出现,笔者认为串岭沟组的地质事件是由于燕山裂陷槽形成早期的火山活动及由其引发的地震事件产 相似文献
997.
998.
CHEN Junren WAN Ling Guangzhou Marine Geological Survey MGMR P. O. Box Guangzhou 《《地质学报》英文版》1999,73(2):216-224
Experimental examinations and analyses have been made of the sediments from drill holes in the Zhuhai area, Guangdong Province. The studies show that there occurred four transgressions in this area over the historical times. The first transgression occurred at 7500 a B.P., with the maxium sea level up to about 1 m above the present level. The second transgression occurred at 5750 a B.P., with the sea level possibly 4 m higher than the present. The third and fourth transgressions took place at 4650 a B.P. and 2600 a B.P. respectively, which lasted for a long time with multiple fluctuations. The fifth transgression is in process. It could be predicted that the sea level at Zhuhai would rise by 15-20 cm in the coming 50 years. 相似文献
999.
1000.
Y.WANG Geological Survey of China 《地质学报》1937,(Z1)
In their geological reconnaissance of Kansu and Kokonor in theautumn of 1935, Messrs. C. C. Sun (孙健初) and T. C. Chow (周宗浚),geologists of the National Geological Survey of China, collected abundantfossils from a thin layer of limestone in the upper part of the so-called 相似文献