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1.
相山铀矿田成矿作用的地球化学模拟 总被引:4,自引:0,他引:4
相山铀矿田是我国最大的火山岩型热液铀矿田,在地质地球化学和高温高压实研究的基础上,利用地球化学模式程序EQ3/6模拟了成矿热水溶液的形成过程和减压排泄区铀成矿作用。计算机模拟结果表明,通过大气降水与碎斑熔岩相互作用,可以形成富含F和SiO2等矿化剂的含铀热水溶液;由于铀以UO2F^3和UO2(CO3(^2-3等配合形式存在,非常稳定,即使在深部强还原环境中仍能能够迁移;酸性和碱性环境,尤其是强酸性 相似文献
2.
WANG Yandong GONG Jianya HUANG Juntao DENG Yuejin WANG Yangdong Doctoral Candidate National Laboratory for Information Engineering in Surveying Mapping Remote Sensing WTUSM Luoyu Road Wuhan China 《地球空间信息科学学报》1999,2(1):104-108
Geo-Spatial Data Transfer Standard is an important part of "National Spatial Data Infrastructure(NSDI)" ,as well as a necessary means for data sharing. "Chinese National Geo-Spatial Data Transfer Format (CNSDTF)" was approved by National Quality Technology Supervise Bureau in 1999 with the standard serial number of 17798-1999. It is designed to support vector and raster spatial data. This paper describes the vector part of CNSDTF, including design ideas, main characters, conceptual model, definition of spatial object, and file structure. 相似文献
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在粒径、密实度较大的卵石层采用正循环机械回转钻进行灌注桩施工,存在钻具类型、合理的泥浆比例和钻探工艺等问题。以西安绕城高速公路谢王立交桥桥桩基工程实践为例,探讨正循环机械回转钻孔灌注桩在卵石层施工工艺等问题。 相似文献
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变质侵入体主要分布于桑格斯帕地区,是从达肯大坂岩群中剔除的一套变质侵入体,和达肯大坂岩群一起构成欧龙布鲁克微陆块的变质基底。变质侵入体常量元素属高分异铝过饱和钾玄岩、高钾钙碱性系列岩浆岩;微量元素显示岩石具火山弧花岗岩特点;稀土元素总体显示轻稀土较为富集、重稀土相对亏损。变质侵入体属于古元古代晚期因不同块体碰撞形成的具有挤压环境特征的火山弧花岗岩。 相似文献
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Vertical transport of selected polycyclic aromatic hydrocarbons (PAHs) in different particle-size fractions of sandy soils
was investigated by simulation experiments in soil columns. Tested soil samples were fractionized into three particle-sizes
including sand, coarse silt and fine silt (2,000–50, 50–20 and <20 μm). Rainfall simulations were conducted in artificially
PAHs contaminated soil columns with 30 cm length and 5 cm diameter in 40 days. PAHs were extracted from soil samples and determined
by high performance liquid chromatography (HPLC). Results showed that the residue level of PAHs in fine silt fraction reached
35.85 mg/kg, which was significantly higher than those in sand and coarse silt fraction (16.28 and 11.80 mg/kg, respectively),
probably because PAHs in macroporous fractions were prone to volatilize or degrade compared with that in microporous fractions.
Linear relationship between the residue levels of individual PAH (R
PAHs) and the value of partition coefficient (log K
oc) was regressed as R
PAHs = 1.55 × log K
oc − 5.86, R
2 = 0.91, n = 9. These results indicated that vertical transport of the mixed PAHs in soils were controlled both by the nature of PAHs
(i.e. log K
oc, molecular weight), soil particle size and soil organic contents, which could influence the transport of PAHs. 相似文献