全文获取类型
收费全文 | 85篇 |
免费 | 22篇 |
国内免费 | 25篇 |
专业分类
测绘学 | 7篇 |
大气科学 | 5篇 |
地球物理 | 12篇 |
地质学 | 72篇 |
海洋学 | 26篇 |
天文学 | 1篇 |
综合类 | 7篇 |
自然地理 | 2篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 7篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1988年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有132条查询结果,搜索用时 640 毫秒
41.
针对目前航空重力测量数据处理中常规搜索方法存在搜索速度慢、正确率低、适用性差的不足,提出以主测线点为搜索中心,采用一定宽度的搜索框对主副测线点进行搜索,将搜索到的主副测线上相邻测点组成线段,运用行列式方法精确求出交叉点及不符值的方法,即滑动窗口搜索法。从搜索时间和正确率两方面对滑动窗口搜索法进行分析,结果表明本文所提方法简单有效,能明显提高测线交叉点搜索效率。 相似文献
42.
泥蚶的性腺发育和生殖周期 总被引:6,自引:0,他引:6
根据生殖细胞发育的宏观和组织切片观察以及各期生殖细胞在滤泡中所占的比例,泥蚶的生殖腺发育过程分为增殖期、生长期、成熟期、排放期和休止期五个阶段。按肥满度的变化并结合性腺组织切片确定,泥蚶的性晚发育在青岛海区一年一个周期。繁殖期在7月上旬至8月下旬,繁殖盛期在7月中旬至8月中旬。至少有二次集中排放过程。 相似文献
43.
Jiang Jianguo Zhou Xuhong Zhang Jiasheng 《Geotechnical and Geological Engineering》2007,25(4):423-429
Using the dynamic differential equation of beam and considering the surrounding soil as dynamic Winkler foundation, the simplified
dynamic interaction factors of group piles are analyzed with axial load under horizontal harmonic load and horizontal seismic
affection. When the axial load was replaced by zero, the expression of dynamic interaction factor would be the same as that
deduced by Markris and Gazetas (1992, Earthquake Eng Struct Dyn 21(2):145–162). And under special situation analysis, there
would be obvious effect on dynamic interaction factor when the axial load was large. The differences are obvious when considering
axial load, and the relative errors would be 14% or greater, so it’s proper to consider axial load when the dynamic interaction
factor are calculated. 相似文献
44.
To understand the potential mechanism of marine extremophiles participating in the formation and the evolution of hydrocarbon
resources in marine extreme environments, some typical kinds of extremophiles and their distributions in marine hydrothermal
and cold vents are discussed and evaluated respectively. The potential relationship between extremophile activities and hydrocarbon
resources in marine extreme environments are then discussed in details. It could be now preliminary concluded that archaea
and bacteria are the two main kinds of extremophiles in marine extreme environments. The dominating microbe communities in
hydrothermal vents are heterotrophic zymogens, sulfate reducers and methanogens, while the ANME-2 group (Methanosarcinales) surrounded by sulfate-reducing bacteria and ANME-1 group dominate in cold vents. Marine extremophiles would be able to use
CH4 and H2S to synthesize energy for metabolism and to support food chains for other unique macrobiota nearby, which together present
a high abundance but a low diversity with distinct characteristics of horizontal and vertical distributions. Marine extremophiles
might play an important role either directly or indirectly in the processes of hydrocarbon formation and subsequent alteration,
and could indicate the evolution of hydrocarbon resources in marine extreme environments. Our research thus has a great significance
both in theoretical approach of potential hydrocarbon resources formed by marine extremophile activities and in practical
exploration of the potential hydrocarbonsource sedimentary layers formed in the Earth history or the potential strata in southern
China.
__________
Translated from Earth Science—Journal of China University of Geosciences, 2007, 32(6): 781–788 [译自: 地球科学—中国地质大学学报] 相似文献
45.
我国海洋鱼类和贝类染色体组型研究进展 总被引:7,自引:1,他引:6
综述迄今为止已报道的我国 38种海洋鱼类和 2 2种海洋贝类的染色体组型 ,以及其中 6种鱼和 1种贝的 C-带、Ag- NOR带等细胞遗传学研究的结果 ,并对这项研究工作存在的问题进行了探讨并对未来作了展望。 相似文献
46.
47.
48.
49.
<正>1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is strictly controlled by fault structures.It has developed to one of the famous production bases of leadzinc and germanium in China. 相似文献
50.