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131.
132.
利用广州白云机场1956~2001年46年的逐时观测资料,通过数理统计和小波分析,揭示出白云机场雷暴气候的演变特征。结果表明:白云机场年平均出现雷暴日数为75.4天,初雷一般在3月1日,终雷一般在10月14日,一年12个月都有可能出现雷暴,其中雷暴多集中出现在4~9月份,以8月份出现最多,12月份出现最少;雷暴的历史演变有着较好的9~12年振荡周期,而且近46年来雷暴的发生有逐渐减小的趋势变化,另外雷暴有明显的季节和日变化特征。 相似文献
133.
复杂的地质作用和控制因素常常使得地球化学元素的分布特征呈非线性,传统的线性模型在处理元素非线性分布具有一定的局限性和不适应性。文中以研究地球化学矿化元素组合为主线,应用aiNet网络模型(带权的不完全连接网络)对地球化学数据做预处理,应用FastICA算法(快速定点独立分量分析)求取矿化元素组合,应用分形含量面积法圈定元素异常下限,应用分形含量梯度法确定元素异常浓集分带,形成了一套地球化学矿化元素组合求异的非线性方法体系,并在西藏洞噶普矿区1∶1万土壤地球化学测量资料的应用中取得了良好的效果。 相似文献
134.
Weihua Ao Wenhui Huang Chengmin Weng Xiuling Xiao Dameng Liu Xiuyi Tang Ping Chen Zhigen Zhao Huan Wan Robert B. Finkelman 《地学前缘(英文版)》2012,3(1):85-95
Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin,northwestern China.The huge reserves of this high quality coal have a high commercial value.We studied the coal’s petrologic characteristics and its maceral distribution to determine the maceral’s contribution to generation of oil and gas.The results show that the Jurassic coals in the Ordos Basin have special penological features because of the Basin’s unique depositional environment which was mainly a series of high-stand swamps in the upper fluvial system.These petrographic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers.After burial,the peat continued to undergo oxidizing conditions,this process generated extensive higher inertinile contents in the coals and the vitrinite components were altered to semi-vitrinite.The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal,dull coal,semilustrous and lustrous coal.The proportions of semi-dull coal and dull coal are higher in the basin margins,especially in the area near the northern margin.The numbers of semilustrous and lustrous coals increase southwards and towards the central basin.This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components.Another observation is that in the Ordos" coal sequences,especially in the lower part,some sandstone beds are thick,up to 20 m with a coarse grain size.The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure.The fusinite structure is clear and well preserved.After burial,the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology.The sand bodies in the roof and floor exhibit good physical conditions so that pore water can maintain a long-term state of oxidation,circulation and connection to the coal.So coal components remain in an oxidation environment for a long time.Conversely,in the basin center,lacustrine facies developed and peat was rapidly covered by mudstone after burial and subsequent coal beds rapidly entered a reducing environment.As a result,abundant gelatification occurred and the vitrinite content increased.Exinite often accumulated in a specific position in the coal bed.Although the average exinite content is not high on the whole,it does significantly contribute to the total hydrocarbon generation. The exinite content has been underestimated,especially the amorphous bituminous fluid and its importance is emphasized here.The reason is that the fluid flows easily into fusinite which has strong rigidity,or flows into some fissures,where it is commonly neglected. 相似文献
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136.
In this paper, we investigate analytically the level space of the imaginary part of quasinormal frequencies for a black hole with a deficit solid angle and quintessence-like matter by the Padmanabhan’s method (Padmanabhan in Class. Quantum Gravity 21:L1, 2004). Padmanabhan presented a method to study analytically the imaginary part of quasinormal frequencies for a class of spherically symmetric spacetimes including Schwarzschild-de Sitter black holes which has an evenly spaced structure. The results show that the level space of scalar and gravitational quasinormal frequencies for this kind of black holes only depend on the surface gravity of black-hole horizon in the range of $-1<w<-\frac{1}{3}$ , respectively. We also extend the range of w to w≤?1, the results of which are similar to that in $-1<w<-\frac{1}{3}$ case. Particularly, a black hole with a deficit solid angle in accelerating universe will be a Schwarzschild-de Sitter black hole, fixing w=?1 and ε 2=0. And a black hole with a deficit solid angle in the accelerating universe will be a Schwarzschild black hole,when ρ 0=0 and ε 2=0. In this paper, w is the parameter of state equation, ε 2 is a parameter relating to a deficit solid angle and ρ 0 is the density of static spherically symmetrical quintessence-like matter at r=1. 相似文献
137.
138.
Ji'en Zhang Wenjiao Xiao Chunming Han Songjian Ao Chao Yuan Min Sun Hongyan Geng Guochun Zhao Qianqian Guo Chong Ma 《Gondwana Research》2011,19(4):958-974
The Karamay area, situated in the eastern part of Western Junggar, Southern Altaids, contains an ophiolitic mélange with ultramafic rocks, gabbro, basalt, chert and limestone, which show typical block-in-matrix structures, and coherent turbidites and tuffs. These lithological associations are interpreted as incoherent and coherent series formed in an accretionary complex. On the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts, duplexes, tilted structures, shear band cleavages, and the NW-verging inclined to overturned folds, we conclude that the overall movement in the accretionary complex was top-to-the-NW. The youngest tuff involved in the deformation contains detrital zircons that have a U–Pb age (LA-MC ICP-MS) of 308 ± 7 Ma. 39Ar–40Ar resistance furnace step-heating of amphibole separates from a diorite dike, which cuts the folded and imbricated rocks in the accretionary prism, yielded a plateau age of 307 ± 2 Ma. Consequently, the age of the deformation in the prism is tightly constrained at 307–308 Ma, implying that the deformation occurred in an extremely short time-span during SE-ward subduction. Combined contemporaneous occurrence of Baogutu adakite, high-Mg, Sr-enriched and Y-poor dioritic dikes, Miaoergou charnockite, and Maliya mafic rocks, we further suggest the accretionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge. 相似文献
139.
基于人均GDP基尼系数及其变化的结构分解,对湖北省区域经济差距的动态变化、产业构成进行了深刻的分析,揭示了20世纪90年代中期以来该省17个地市州之间人均GDP差距及其变化的动力机制。结果表明,非农产业是湖北省区域经济差距的决定性因素,而非农产业尤其是第二产业地理集中程度的提高又是推动湖北省区域经济差距扩大的主导性因素。缓解湖北省区域经济差距的现实选择并不仅仅局限于加快落后地区非农产业发展,还应该促进生产要素流动,推动人口向工业化程度高的地区集中,降低湖北省生产与人口地区分布的不一致性。 相似文献
140.
Chunming Han Wenjiao Xiao Guochun Zhao Benxun Su Songjian Ao Jien Zhang Bo Wan Zhongmei Wang Jiaxin Ding Wenjun Qu Andao Du 《Resource Geology》2014,64(3):247-261
The Hongqiling Cu–Ni sulfide deposit in central Jilin Province is located in the eastern part of the Central Asian Orogenic Belt. Rhenium and osmium isotopes in sulfide minerals from the deposit are used to determine the timing of mineralization and the source of osmium, and ore metals. Sulfide ore samples have osmium and rhenium concentrations of 0.28–1.07 ppb and 2.39–13.17 ppb, respectively. Ten analyses yield an isochron age of 223 ± 9 Ma, indicating that the Cu–Ni sulfide deposit in the area formed in the Triassic. The initial 187Os/188Os ratio is around 0.295 ± 0.019 (MSWD = 1.14) and the δ34S values of sulfide ores vary from ?1.50 to +3.00‰. These data indicate that the mineralizing materials were derived mainly from a mantle with some quantities of crustal components introduced into the rock‐forming and ore‐forming systems during mineralization and magmatic emplacement. 相似文献