全文获取类型
收费全文 | 62篇 |
免费 | 7篇 |
国内免费 | 35篇 |
专业分类
大气科学 | 1篇 |
地球物理 | 16篇 |
地质学 | 75篇 |
海洋学 | 4篇 |
天文学 | 1篇 |
综合类 | 2篇 |
自然地理 | 5篇 |
出版年
2024年 | 3篇 |
2023年 | 5篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
排序方式: 共有104条查询结果,搜索用时 890 毫秒
51.
Relations between A-type granites and copper mineralization as exemplified by the Machangqing Cu deposit 总被引:4,自引:0,他引:4
This paper deals with the relations between the Machangqing rockbody which corresponds to the A-type granites and porphyry
copper mineralization in terms of petrochemistry, trace element geochemistry, fluid inclusion geochemistry and isotope geochemistry.
The results show that the Machangqing porphyry copper deposit was formed from the fluid predominated by mag-matic fluid. This
kind of ore-forming fluid was just differentiated from the magma responsible for the A-type granites. Therefore, as viewed
from whether they contain water or not, the A-type granites can, at least, be divided into two types: water-bearing and water-free.
The water-bearing A-type granites can serve as the host of porphyry copper deposits under certain geological conditions. 相似文献
52.
内蒙大青山早前寒武纪变质岩和早期陆壳的演化 总被引:1,自引:0,他引:1
将大青山地区早前寒武纪变质岩石分成三个岩性构造组合.即(1)麻粒岩—紫苏花岗岩组合;(2)角闪片麻岩—英云闪长岩组合;(3)富铝片麻岩—钾质花岗岩组合.其中,组合(1)是区内最古老的物质组成,其形成时代至少应在晚太古代以前(>2800Ma).组合(2)是具花岗—绿岩带特征的晚太古代中、低级变质岩系.组合(3)是经早元古造山变质作用形成的岩石组合.根据重新排定的地质事件顺序,对本区早期地壳演化的有关问题进行了讨论. 相似文献
53.
Geochemical enrichment and mineralization of indium 总被引:20,自引:0,他引:20
Indium occurs in a very dispersed manner in nature with enrichment of economic interest rarely known. The highly dispersed
nature of indium, among several other elements, has for a long time retarded our understanding of the regularities that control
their mineralization, which in turn has hindered exploitation and application of these elements. Recent studies of ours show
that no significant enrichment of indium can be recognized in various types of Pb-Zn sulphide deposits as well as in deposits
of copper, iron and manganese. Indium concentrations in ores of these deposits are generally below 10 × 10-6. In contrast, however, indium is found to be enriched to a significant extent in cassiterite-sulphide deposits and some tin-rich
Pb-Zn polymetallic deposits. The average content of indium in these deposits can be over 100 × 10-6, and more than 90% of it is concentrated in sphalerite. Generally, these deposits may be considered as large paragenic deposits
for indium and, therefore, there must be some regularities that govern the geochemical enrichment of the so-called “dispersed
element” indium.
This project was financially supported by the National Natural Science Foundation of China (No. 49633110). 相似文献
54.
Abstract According to the kinds of feldspar and rock associations in the Al-rich gneisses, the low-pressure metamorphic crust of the Early Proterozoic granulite facies in central Inner Mongolia can be divided into southern and northern belts which are composed of six rock associations. They represent the relevant rock sequences of the layered metamorphic rock series formed under specific metamorphic temperature and pressure conditions as well as tectonic environments. Mineral inclusions and reaction texture have recorded that the medium-temperature high-pressure mineral assemblages are replaced by the high-temperature low-pressure mineral assemblages, thus, giving rise to: garnet+quartz? hypersthene+plagioclase; kyanite? sillimanite and garnet+ kyanite / sillimanite+quartz? cordierite. The deformation fabrics of the rocks, the change of mineral assemblages and the PTt path of metamorphism indicate that the contempranceous high-temperature normal-slip ductile shearing is the main cause of the formation of the low-pressure metamorphic crust of granulite facies. In the orogenic event, the co-action of thrusting and extension resulted in the change of a medium-temperature high-pressure metamorphic environment into the high-temperature low-pressure metamorphic conditions. 相似文献
55.
液态水影响不同煤级煤吸附甲烷的差异及其机理 总被引:3,自引:0,他引:3
以IS100等温吸附解吸仪和MTS815型电液伺服岩石实验系统为主要实验平台,应用已建立的模拟储层条件下煤样注水和注水试样等温吸附实验方法,对3种不同煤级的煤储层样品开展了高压(8~20 MPa)注水和等温吸附实验,发现储层条件下煤层中的液态水(注水煤样)对不同煤级(0.46%<Ro,max<1.72%)煤吸附甲烷影响有差异,其含水量随煤级升高呈L型降低,而吸附量则线性增加。笔者认为液态水造成吸附差异的原因是煤体润湿性的差异,对于中低煤级的煤样来说,煤表面的物理化学性质起着控制作用,直接影响着煤体润湿性,吸附势和含水量的曲线都说明了这一点。 相似文献
56.
<正>The Bohai Bay Basin is a Mesozoic subsidence and Cenozoic rift basin in the North China Craton.Since the deposition of the Permo-Carboniferous hydrocarbon source rock,the basin has undergone many tectonic events.The source rocks have undergone non-uniform uplift,twisting,deep burying,and magmatism and that led to an interrupted or stepwise during the evolution of hydrocarbon source rocks.We have investigated the Permo-Carboniferous hydrocarbon source rocks history of burying,heating,and hydrocarbon generation,not only on the basis of tectonic disturbance and deeply buried but also with new studies on apatite fission track analysis,fluid inclusion measurements,and the application of the numerical simulation of EASY%R_o.The heating temperature of the source rocks continued to rise from the Indosinian to Himalayan stage and reached a maximum at the Late Himalayan.This led to the stepwise increases during organic maturation and multiple stages of hydrocarbon generation.The study delineated the tectonic stages, the intensity of hydrocarbon generation and spatial and temporal distribution of hydrocarbon generations.The hydrocarbon generation occurred during the Indosinian,Yanshanian,and particularly Late Himalayan.The hydrocarbon generation during the late Himalayan stage is the most important one for the Permo-Carboniferous source rocks of the Bohai Bay Basin in China. 相似文献
57.
Based on the production data of a large number of surface drainage wells in the Huainan mining area,the present study shows that four types of typical production characteristics for relieved methane wells are recognized,of which the stable type for production and gas concentration is the most dominate,as determined by a comprehensive study on the volume and concentration of drained gases, as well as the stress changes of rocks influenced by mining.Some influence factors for the productive differences of ... 相似文献
58.
59.
本文设想把华北陆台北缘前寒武纪变质岩区韧性剪切变形-变质带中金矿成矿作用做为区域变质作用-构造作用-岩浆作用旋回中的一部分。这类金矿主要形成在这一旋回的晚期,变质地质体被抬升的阶段,并就位于低温韧-脆性变形变质带中,属于各种内动力地质作用的综合产物。分析韧性剪切变形-变质带(DDMZ)内金矿成矿过程中的这种多因素、多阶段的各种信息,我们提出如下参数:区域性参数富铁质变质岩石组合和壳型剪切带;最佳区段参数—低温韧-脆性变形-变质带和弱碱性钾质花岗岩;金矿化带参数—岩石-流体交代带。其目的是明确找矿目标,提高金矿预测有效性。 相似文献
60.
Active layer thickness variations on the Qinghai–Tibet Plateau under the scenarios of climate change
Qiangqiang?PangEmail author Lin?Zhao Shuxun?Li Yongjian?Ding 《Environmental Earth Sciences》2012,66(3):849-857
Climate change has greatly influenced the permafrost regions on the Qinghai–Tibet Plateau (QTP). Most general circulation
models (GCMs) project that global warming will continue and the amplitude will amplify during the twenty-first century. Climate
change has caused extensive degradation of permafrost, including thickening of the active layer, rising of ground temperature,
melting of ground ice, expansion of taliks, and disappearance of sporadic permafrost. The changes in the active layer thickness
(ALT) greatly impact the energy balance of the land surface, hydrological cycle, ecosystems and engineering infrastructures
in the cold regions. ALT is affected by climatic, geographic and geological factors. A model based on Kudryavtsev’s formulas
is used to study the potential changes of ALT in the permafrost regions on the QTP. Maps of ALT for the year 2049 and 2099
on the QTP are projected under GCM scenarios. Results indicate that ALT will increase with the rising air temperature. ALT
may increase by 0.1–0.7 m for the year 2049 and 0.3–1.2 m for the year 2099. The average increment of ALT is 0.8 m with the
largest increment of 1.2 m under the A1F1 scenario and 0.4 m with the largest increment of 0.6 m under the B1 scenario during
the twenty-first century. ALT changes significantly in sporadic permafrost regions, while in the continuous permafrost regions
of the inland plateau ALT change is relatively smaller. The largest increment of ALT occurs in the northeastern and southwestern
plateaus under both scenarios because of higher ground temperatures and lower soil moisture content in these regions. 相似文献