全文获取类型
收费全文 | 39篇 |
免费 | 10篇 |
国内免费 | 16篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 22篇 |
地球物理 | 2篇 |
地质学 | 20篇 |
海洋学 | 5篇 |
天文学 | 10篇 |
综合类 | 1篇 |
自然地理 | 4篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
排序方式: 共有65条查询结果,搜索用时 15 毫秒
61.
Fang Liu Xin Li Ya J. An Jie Li Zhao F. Zhang 《Geostandards and Geoanalytical Research》2019,43(3):509-517
In this study, to evaluate whether bias free Ca isotope ratios can be properly achieved by thermal ionisation mass spectrometry (TIMS) using the 42Ca–43Ca double‐spike technique without chemical purification, a series of comparable experiments (with or without column chemistry) were made on Ca‐dominated minerals and rocks. Minerals, including fluorite, calcite, titanite and apatite, displayed similar Ca isotope ratios with Δ44/40Cawith‐without ranging from ?0.02 to +0.07‰. For Ca‐rich rocks, we mainly focused on the carbonates since they are the main repositories of Ca at the surface of the Earth. Coral, stalagmite, carbonatite, dolomite, marble and limestone are studied here. Interestingly, δ44/40CaSRM 915a of these minerals and rocks without chemical purification displayed little drift compared with that of rocks with chemical purification, with Δ44/40Cawith‐without merely spanning from ?0.04 to +0.04‰. This implies that Ca isotope ratios can be achieved without column chemistry, possibly due to a property of TIMS in which Ca ions are only ionised at a target temperature and with a specific activator without ionising other ions. Therefore, for Ca‐dominated minerals or rocks, we suggest that column chemistry is unnecessary if they are totally dissolved and mixed in proper proportion with the 42Ca–43Ca double spike for TIMS measurement. 相似文献
62.
The results obtained by Kroupa, Petr & McCaughrean (1999) for specific models of young compact binary-rich clusters are generalised using dynamical scaling relations, to infer the candidate set of possible birth models leading to the Orion Nebula Cluster (ONC), of which the Trapezium Cluster is the core. It is found that candidate sets of solutions exist which allow the ONC to be in virial equilibrium, expanding or contracting. The range of possible solutions is quite narrow. These results will serve as guidelines for future, CPU-intensive calculations of the stellar-dynamical and astrophysical evolution of the entire ONC. These, in turn, will be essential to quantify observables that will ultimately discriminate between models, thus allowing us to understand if the ONC is in the process of assembling a rich Galactic cluster, and, if this is the case, how it occurs. 相似文献
63.
In Part Ⅰ, the authors succeeded in coupling the spectral atmospheric model (SAMIL_R42L9) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP/CAS) with the land surface model, Atmosphere-Vegetation-Interaction-Model (AVIM) and analyzed the climate basic state and land surface physical fluxes simulated by R42_AVIM. In this Part Ⅱ, we further evaluate the simulated results of the biological processes, including leaf area index (LAI), biomass and net primary productivity (NPP) etc. Results indicate that R42_AVIM can simulate the global distribution of LAI and has good consistency with the monthly mean LAI provided by Max Planck Institute for Meteorology. The simulated biomass corresponds reasonably to the vegetation classifications. In addition, the simulated annual mean NPP has a consistent distribution with the data provided by IGBP and MODIS, and compares well with the work in literature. This land-atmosphere coupled model will offer a new experiment tool for the research on the two-way interaction between climate and biosphere, and the global terrestrial ecosystem carbon cycle. 相似文献
64.
65.
辽南42号金伯利岩岩管主要由东部42-1号大岩管、西部42-2号小岩管和中部42-3号小小岩管组成。42-1号岩管从地表到40 m标高形态急剧收缩;42-2号岩管为烟筒状,40 m标高至-160 m标高面积比为1∶1.15;42-3岩管在-200 m标高处延深为脉状。42号岩管岩石类型为斑状金伯利岩、斑状富金云母金伯利岩、含或富含围岩角砾金伯利岩和含岩球斑状金伯利岩。岩石化学特征研究表明,岩石中w(SiO2)、w(Al2O3)、w(TiO2)值比山东胜利Ⅰ号金伯利岩和戴里值偏高,w(MgO)、w(Cr2O3)、w(K2O)、w(Na2O)、w(P2O5)值较戴里值偏低,但w(K2O)、w(Na2O)、w(P2O5)值比山东胜利Ⅰ号金伯利岩略高;w(ΣFe2O3+FeO)、w(CaO+H2O)值与山东胜利Ⅰ号金伯利岩及戴里值相当。通过采样分析42-2号岩管金刚石含量高,42-1号岩管金刚石含量低;研究认为受造岩矿物橄榄石和金云母的影响,金刚石含量与橄榄石斑晶含量正相关,与金云母含量呈负相关;伴生矿物铬铁矿、镁铝榴石、碳硅石含量高,则金刚石含量也随之增高,为正相关;而锐钛矿于金刚石含量为负相关。基于研究区的三维建模、推覆构造研究,推测42号岩管不是根部相,其东部可能存在深部金伯利岩体。 相似文献