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101.
物探在豫西隐伏金矿找矿中的应用   总被引:1,自引:0,他引:1  
结合成矿地质条件,简要介绍了磁法、甚低频电磁法、瞬变电磁法、激电测深在金矿找矿工作中的不同特点和作用;给出了在豫西几个金矿区多金属成矿带上寻找隐伏金矿体的成功实例,说明在具备地球物理前提的条件下,用磁法、甚低频电磁(或瞬变电磁)法快速扫面测量可圈定找矿靶区。在找矿靶区做一定量对称四极激电测深工作,可预测矿体埋藏深度等;这是经济、快速地探测浅—深部隐伏、半隐伏盲矿体的有效方法,值得推广应用。  相似文献   
102.
矿集区大地电磁噪声场源分析及噪声特点   总被引:1,自引:0,他引:1  
结合长江中下游某矿集区大地电磁观测环境,分析大型矿山、通讯基站及其他主要电磁噪声源对视电阻率曲线的影响.依据时域波形将噪声分为脉冲噪声、周期噪声、三角波噪声、方波噪声、阶跃噪声、似充放电模式的三角噪声,便于在后期资料处理过程中针对不同的噪声类型对大地电磁数据进行降噪处理.  相似文献   
103.
广域电磁法深部找矿实验效果   总被引:1,自引:0,他引:1  
介绍了广域电磁法的基本原理、特点及广域视电阻率的定义。在内蒙古自治区某银铅锌矿进行了实验勘探工作,解释和推断了地电异常,并和可控源音频大地电磁法的效果进行了对比。研究结果表明:广域电磁法可以用较小的发收距获得较大的探测深度,勘探效率和精度较高,用于寻找深部金属矿的效果明显。  相似文献   
104.
The Dehe granitic pluton intruded the Xiahe Group which is in the core complex of the North Qinling Orogenic Belt(NQOB).It shows gneissic bedding and possesses typical S-type granite minerals such as muscovite and garnet.LA-ICP-MS U-Pb isotopic dating of the Dehe granite yielded a weighted average age of 925±23 Ma which represents the emplacement age of the pluton.Most of the εHf(t) values are negative,and the two-stage model ages are consistent with the age of the Qinling Group.The isotope data show that the Dehe granite was formed in the following geological setting:in the syn-collision setting of the NQOB in the Neoproterozoic,crustal thickening induced partial melting of materials derived from the Qinling complex,and then the maga upwelled and intruded into the Xiahe Group.The formation of the Dehe S-type granite implied the occurrence of a convergent event in the QOB during the Neoproterozoic.  相似文献   
105.
应用瞬变电磁法小线框大电流探测隐伏断层   总被引:1,自引:0,他引:1  
瞬变电磁法小线框、大电流技术在金属矿勘探和地下水的探测中已趋成熟。在长期实践的基础上,分析断层上方出现的感应二次场V2 负值现象和成因,提出断层和次新断层以及地质塌陷的探测方法和数据处理的要点,总结出利用小线框、大电流瞬变电磁法探测隐伏断层的技术方法。钻井验证表明,该方法施工快速轻便,断层点定位准确。  相似文献   
106.
Field geological investigation and geochemical analysis are carried out on Baya’ertuhushuo Gabbro in South Great Xing’an Range. Field investigation reveals that the gabbro is a magmatic intrusion rather than a component of an ophiolite suite as previously thought. Zircon laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) U-Pb dating indicates the gabbro was formed in 274–275?Ma, just as the widespread volcanic rocks of Dashizhai Formation (P1d), monzogranites and miarolitic alkali-feldspar granites in the study area. The gabbro has SiO2 content between 47.23 wt% and 50.17 wt%, high MgO and FeOT contents of 6.95–11.29 wt% and 7.32–12.24wt%, respectively, and it belongs to low-K tholeiitic series in the SiO2-K2O diagram. The Chondrite-normalized rare earth element (REE) patterns and primitive mantle-normalized spider diagrams of the gabbro are similar to those of Normal Mid-Ocean Ridge Basalt (N-MORB) except for the enrichment of large ion lithophile elements (LILE), such as Rb, Ba and K. In trace element tectonic discriminative diagrams, the samples are mainly plotted in the N-MORB field, and Zircon in?situ Lu-Hf isotopic analysis also indicates the gabbro originated from depleted mantle. Through synthetic studies of the geochemical characteristics and petrogenesis of Baya’ertuhushuo gabbro, volcanic rocks of Dashizhai Formation and granitoids in the area, it is suggested that the early Permian magmatism in the Xilinhot-Xiwuqi area formed in the tectonic setting of asthenosphere upwelling, which was caused by breaking-off of the subducted Paleo-Asian Ocean slab.  相似文献   
107.
Tectono-geochemical samples were systematically collected from 5 drillcores along the No. 304 explora-tion line and at the -310 m level under the pit in the mining area, totalling 705 samples from the metamorphic rocks, granites, altered rocks and orebodies, and were determined for their contents of 20 kinds of elements including Au, Ag, As, Sb, Hg, Cu,,Pb, Zn, Sn, Bi, Mo, Co, Ni, Mn, Cr, V, Ti, Ba, Rb, Sr, etc. By using the Surfer software the geochemical exploration line profile maps for the 20 kinds of elements and the curves for the element geochemical contents of individual ore vein groups were established. In conbination with the geochemical map analytical method and Gregorian’s zoning index calculation method, the vertical, longitudinal and lateral zonation sequences of the elements were ascertained and the geochemical three-dimentional zonation model of the primary halos was estab-lished on the basis of the analysis of metallogenic structures and alteration zonation. Coupled with the results of analysis of the geology and geochemistry data, it may be concluded that the process of alteration of granites in the mining area is also accompanied with the process of gold enrichment and mineralization. With the intensification of alteration of granites from granite →potash feldspathization granite →sericite-quartz alteration granite, seric-ite-quartz rocks →beresitized granite, pyrite sericite-quartz rock, silicified granite →gold ore, the contents of thio-phile ore-forming elements such as Au, Ag, As, Cu, Bi, Mo, Pb, Sb, Hg, and Sn tended to increase. Factor analysis of trace elements indicated: factor F2 (Au, Ag, Cu, Sn, As) represents the element association brought in at the main stage of hydrothermal metallogenesis; factor F4 (Bi, Sb) and factor F5 (Pb, Zn) represent the ore-forming element association supperposed during the late stage of Au-bearing sulfides. By using the Gregorian’s zoning index and map analysis method we have ascertained the primary halo axial zonation sequence (form frontal halo →tail halo): Pb, Zn, Mn, Ba, Sr, Rb, As, Sb, Ag, Cu, Sn, Mo, Au, Bi, Hg, Ti, Cr, V, Ni, and Co. The geochemical anomalies in the mining area display a tendency of lateral plunging to WS, which is consistent with the lateral plunging of orebodies and mineralization alteration zone. Comprehensive analysis of the results of investigations on ore-controlling structures, mineralization-alteration zonation and geochemical zonation of the primary halos indicates that the gold orebodies in this area are still of greater extension.  相似文献   
108.
The Erlihe Pb–Zn deposit is an important mine of the Pb–Zn metallogenic zone in the South Qinling Orogen. It has been considered a sedimentary exhalative deposit in previous investigations because the ore body occurs concordantly at the transitional location of an upright fold. Re and Os isotopic analyses for paragenetic pyrites with sphalerite and galena from the ore body have been used to determine the timing of mineralization and to trace the source of metallogenic materials. The Re–Os isotopic data of four pyrite samples construct an isochron, yielding a weighted average age of 226±17 Ma (mean square weighted deviation=1.7), which is considered the main mineralization age. A dioritic porphyrite vein sample, showing weaker mineralization, was also dated using the SHRIMP zircon U–Pb isotopic method to constrain the youngest metallogenic age of the ore deposit, because it distributes along a group of tensional joints cutting not only the upright fold in the deposit field, but also the main ore bodies. The dioritic porphyrite sample yields a weighted mean 206Pb/238U age of 221±3 Ma, which is slightly younger than the Re–Os isotopic isochron age of the pyrites, considered as the upper age limit of the mineralization, namely the ending age of the mineralization. The Os isotopic compositions of sulfide minerals distribute within a range between Os isotopic compositions of the crust and the mantle, indicating that the ore deposit can be derived from magma-related fluid, and the metallogenic materials are most likely derived from the mixing source of the crust and the mantle. The Erlihe Pb–Zn deposit and associated dioritic porphyrite vein, important records of Qinling tectonic–magmatism–mineralization activities, were formed during the Triassic collisional orogeny processes.  相似文献   
109.
In this paper,we report an integrated study of U-Pb age and Hf isotope compositions of zircons from biotite plagioclase gneiss at Lianghe in western Yunnan.The zircons preserved inherited core and rim texture.Igneous zircon grains and rims yielded a weighted mean ~(206)Pb/~(238)U age of 120.4±1.7 Ma,theirε_(Hf)(120 Ma)values were mainly negative ranging from-13.9 to-10.7,with Hf model ages between 1.9 Ga and 2.0 Ga,some zircons had positiveε_(Hf)(120 Ma)values ranging from 0.2 to 2.1.The inherited cores ...  相似文献   
110.
文章通过对南岭东段寨背和陂头岩基地质-岩石地球化学特征研究,判明它们的侵位深度(7.5 km)、围岩温度(250℃)及岩浆初始温度(950℃),建立起寨背-陂头岩基的数学计算模型,并计算得出:寨背和陂头花岗岩熔体侵位后,其初始温度降低至结晶温度所需的时间(Δtcol)分别为4.04 Ma(寨背岩基)和3.97 Ma(陂...  相似文献   
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