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排序方式: 共有107条查询结果,搜索用时 15 毫秒
81.
近年来,袭警事件频繁发生,如何保障警员安全至关重要.基于北斗卫星导航系统和惯性导航,结合生物传感器、网络通信、深度学习和地理信息系统,设计出一套警员联动保护系统.该系统可动态跟踪警员位置,实时感知其生理指标,智能判其所处状态,并能在危机时刻,将相关信息及时送达控制中心,辅助制定救援策略.本研究对保障广大执法人员和人民生...  相似文献   
82.
蓝家庄金矿床位于牟平-乳山金成矿带南部,为一处严格受构造控制的蚀变岩型为主石英脉型次之的大型金矿床。控矿构造内煌斑岩的大量出现,显示控矿构造具有贯通下地壳的特点,可以为幔源含矿岩浆流体浅部就位提供空间条件。研究认为矿化蚀变带中心发育的正长斑岩与金成矿关系密切;矿床地质特征和穿插关系显示矿床形成经历了4个热液成矿期,第Ⅱ和第Ⅲ成矿阶段(石英-黄铁矿和石英多金属硫化物阶段)为主要的金成矿期,矿物组合特征显示应属浅成低温热液矿床;矿床深部可能发育的超壳断裂和斑岩体,为研究胶东金矿矿床成因提供了新视角。  相似文献   
83.
甘肃寨上超大型钨、金(锑)多金属矿床位于西秦岭岷-礼成矿带西段,属于复合矿床,具有显著的多期次、多物源和多成因特点.年代学结果表明,矿区至少存在早期钨矿化(220 Ma)和晚期金矿化(140~120 Ma)两期成矿作用.钨矿为破碎蚀变岩型,矿质主要来源于岩浆热液,在时空和成因上与同时代富钨的闪长玢岩脉(220~210 ...  相似文献   
84.
In order to improve CO2 capture, utilization and storage (CCUS) to solve carbon emission, sandstone from the Triassic Liujiagou Formation (LF) from the Ordos Basin in China was investigated using permeability tests and computed X-ray tomography (CT) scanning. The presence of reactive minerals within the geological CO2 sequestration target storage formation can allow reaction with injected CO2, which changes the porosity and permeability of the LF beds, affecting storage effectiveness. To investigate the effect of chemical reactions on the pore structure and permeability of sandstone cores representing the LF CO2 storage, tests were conducted to analyze the changes in porosity and permeability of sandstone cores induced by CO2-saturated brine at different reaction times (28-day maximum reaction period). Porosity and permeability of the sandstone increased after reaction with CO2-saturated brine due to mineral dissolution. The sandstone exhibited an increase in porosity and permeability after 15 days of reaction with CO2-saturated brine. Moreover, there was an increase in the volume of large pores in the sandstone after the 28-day period. The pore network of the sandstone was established through CT results, and the porosity calculated based on the obtained pore network was close to that measured in the test, demonstrating the feasibility to use CT to study the evolution of the microstructure of sandstone after long-time exposure to CO2-saturated brine.  相似文献   
85.
刘伟  袁洪  周韩雯 《测绘学报》2011,(Z1):133-136,144
针对捷联式陀螺寻北倾斜误差补偿,对坐标变换法和矢量法两种解析调平算法进行推导,修正参考文献中有关矢量解析调平算法的错误;给出两种形式不同但寻北结果相同的解析调平解算公式,并对两种算法的寻北精度进行比较,仿真与试验结果表明了两种解析调平算法的正确性。  相似文献   
86.
U–Pb ages, trace elements, and Hf isotope compositions of zircons from the Mayuan migmatite complex in NW Fujian province have been determined to provide constraints on the source and genesis of anatexis and tectonothermal evolution related to the Caledonian orogeny in South China. The migmatites investigated consist of various amounts of mesosome, leucosome, and melansome. Zircons extracted from mesosome, leucosome, and granite samples are characterized by oscillatory overgrowths enclosing inherited cores or occur as newly grown grains. The ages of the inherited zircons from the leucosome and granite samples are consistent with those of adjacent basement paragneiss in the study area, suggesting that both leucosome and granite were generated by partial melting of the latter. A comparison of Hf isotopes between the newly-formed zircons and inherited cores indicates that the former resulted from the breakdown of preexisting inherited zircons and/or less Hf-rich minerals other than zircons at the source. One mesosome sample contains typical metamorphic zircons that yielded a weighted mean 206Pb/238U age of 453 ± 3 Ma. They show enrichments in heavy REEs (LuN/LaN up to 22,709), indicating their growth prior to garnet crystallization. The other mesosome sample, in contrast, contains both newly-formed metamorphic rims and grains that gave a weighted mean 206Pb/238U age of 442 ± 8 Ma. They are characterized by relatively low Th/U ratios, depletions in heavy REEs (LuN/LaN = 117–396), and low 176Lu/177Hf ratios, suggesting their growth synchronous with garnet crystallization. The U–Pb ages of the mesosome samples are interpreted as recording the time of early (ca. 453 Ma) to peak (442 Ma) stages of a regional metamorphic event. Two leucosome and two granite samples yield consistent U–Pb ages of 438 ± 5 Ma to 442 ± 4 Ma, which provide constraints on the timing of subsequent anatexis and magmatism. The geochronological data reported here reveal a consecutive sequence of regional metamorphism, anatexis, and magmatism in NW Fujian province, lasting for at least 15 Myr, which was driven by the Caledonian orogeny that have affected a major part of the SCB.  相似文献   
87.
云开隆起区热中心式区域混合岩的成因研究   总被引:1,自引:0,他引:1       下载免费PDF全文
周汉文  游振东 《地球科学》1997,22(3):332-338,T001
云开隆起区不同混合岩化程度的混合岩在空间多以黑云母花岗岩为中心,呈环带状分布,混合岩的矿物空间分布研究表明,亲成体矿物具有随机分布特点,说明为熔浆结晶成因,结晶温度在560-580℃,条带状混凳夺的质量平衡研究表明,新成体和古成体的成分具有很好的相关性,递进熔融作用合理解释了这种混合岩的成因及其空间分布规律。  相似文献   
88.
Widely developed in the Dabie complex are various disequilibrium textures which provide direct evidence for the evolution of metamorphism and late-stage uplifting history.The typical mineral assemblasge in the Opx-Gt-Pl-Bi gneiss in Huangtuling,Luotian County,Hubei Province,Is Opx(I) Gt Pl(I) Bi(I) Q.The corona composed of cordierite and orthopyroxene(Ⅱ)growing around garnets in the granulite makes it clear that there occurres the following metamorphic reaction:Gt Q→Cd Opx(Ⅱ).It is estimated that the gran ulite-forming temperature(T)and pressure(P)are 857-998℃ and 1.18-1.23Gpa,respectively,and the corona was formed under the following conditions:T=829-911℃ and P=0.52-0.59GPa.The above results indicate that There occurred a rapid and nearly adiabatic uplifting event and a decompressional metamorphism in the Dabie complex after the formation of granulite.As compared with the granulites worldwidely distributed in 90 locations(Harley 1989),the Huangtuling granulite should belong to the high-pressure type,which represents the composition of the crust at a depth of more than 40 kilometers.  相似文献   
89.
In the Central Orogenic Belt, China, two UHP metamorphic belts are discriminated mainly based on a detailed structural analysis of the Kanfenggou UHP metamorphic fragment exposed in the eastern Qinling orogen, and together with previous regional structural, petrological and geochronological data at the scale of the orogenic domain. The first one corresponds to the South Altun-North QaidamNorth Qinling UHP metarnorphic belt. The other is the Dabie-Sulu UHP and HP metamorphic belts. The two UHP metamorphic belts are separated by a series of tectonic slices composed by the Qiniing rock group, Danfeng rock group and Liuling or Foziling rock group etc. respectively, and are different in age of the peak UHP metamorphism and geodynamic implications for continental deep subduction and collision. Regional field and petrological relationships suggest that the Kanfenggou UHP metamorphic fragment that contains a large volume of the coesite- and microdiamond-bearing eclogite lenses is compatible with the structures recognized in the South Altun and North Qaidam UHP metamorphic fragments exposed in the western part of China, thereby forming a large UHP metamorphic belt up to 1000 km long along the orogen strike. This UHP metamorphic belt represents an intercontinental deep subduction and collision belt between the Yangtze and Sino-Korean cratons, occurred during the Paleozoic. On the other hand, the well-constrained Dabie-Sulu UHP and HP metamorphic belts occurred mainly during Triassic time (250-220 Ma), and were produced by the intracontinental deep subduction and collision within the Yangtze craton. The Kanfenggou UHP metamorphic fragment does not appear to link with the DabieSulu UHP and HP metamorphic belts along the orogen. There is no reason to assume the two UHP metamorphic belts as a single giant deep subduction and collision zone in the Central Orogenic Belt situated between the Yangtze and Sino-Korean cratons. Therefore, any dynamic model for the orogen must ac-count for the development of UHP metarnorphic rocks belonging to the separate two tectonic belts of different age and tectono-metamorphic history.  相似文献   
90.
Abstract   Major and trace elements and Sm–Nd isotopic data are presented for metabasites that are present as lenses within Paleozoic metasediments in the Chenxing and Bangxi regions, central Hainan Island, Southeast (SE) China. Most metabasites are metamorphosed cumulated gabbroic rocks tholeiitic in nature, and characterized by varying degrees of depletion in Th, Nb, Ta and light rare earth elements (LREE). Moreover, they show high positive ∈Nd(T) values of approximately +7, similar to those of mid-ocean ridge basalts (MORB). A Sm–Nd isochron age of 333 ± 12 Ma obtained for the metabasites is interpreted as their crystallization age. The combined geochemical and Sm–Nd isotopic data suggest that the metabasites were generated by dynamic partial melting from a MORB-like mantle source in an oceanic regime. These rocks probably represent remnants of fragmented oceanic crust of the eastern part of Paleo-Tethys. They were obducted onto the continental crust as part of the 'Shilu Mélange' in earliest Mesozoic time when southern Hainan (part of the Indochina block) collided with northern Hainan (part of South China). Alternatively, they could be formed in a volcanic rifted passive margin at the sea-floor spreading stage as part of MORB-like seaward-dipping reflector break-up packages.  相似文献   
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