全文获取类型
收费全文 | 1247篇 |
免费 | 600篇 |
国内免费 | 1195篇 |
专业分类
测绘学 | 52篇 |
大气科学 | 167篇 |
地球物理 | 706篇 |
地质学 | 1800篇 |
海洋学 | 69篇 |
天文学 | 91篇 |
综合类 | 92篇 |
自然地理 | 65篇 |
出版年
2021年 | 1篇 |
2015年 | 1篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 183篇 |
2010年 | 99篇 |
2009年 | 165篇 |
2008年 | 43篇 |
2007年 | 114篇 |
2006年 | 223篇 |
2005年 | 264篇 |
2004年 | 504篇 |
2003年 | 294篇 |
2002年 | 235篇 |
2001年 | 174篇 |
2000年 | 113篇 |
1999年 | 78篇 |
1998年 | 89篇 |
1997年 | 98篇 |
1996年 | 67篇 |
1995年 | 56篇 |
1994年 | 40篇 |
1993年 | 92篇 |
1992年 | 59篇 |
1991年 | 18篇 |
1990年 | 2篇 |
1989年 | 11篇 |
1988年 | 1篇 |
1987年 | 8篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有3042条查询结果,搜索用时 772 毫秒
931.
从波动观点看塔北地区油气藏的形成演化:以英买7油藏为例 总被引:6,自引:0,他引:6
本文运用沉积波动过程分析方法,在综合分析野外露头、岩心、录井、测井、地震等资料的基础上,建立了塔北地区不同小区的岩性-时间剖面。研究表明,740 ̄760Ma、200 ̄240Ma、100 ̄110Ma、60 ̄70Ma、30Ma是控制塔北地区构造演化的主要周期。早古生代、三叠纪和第三纪以来是3次主要的沉积高峰,志留纪末-晚泥盆世早期为主要肃蚀期,肃蚀量一般〉1000m,北部〉1500 ̄2000m,海西期 相似文献
932.
内蒙古大乃林沟角闪石岩岩石学特征 总被引:2,自引:0,他引:2
内蒙古克什克腾旗内兴乡大乃林沟角闪石岩呈脉状产于侏罗纪中酸性火岩中,具明显的隐爆特征,晶洞构造发 要矿物发为富铁普通角闪石,含量一般〉90%。全岩SiO2含量为 38.65%~41.24%,TFeO为19.00%~32.94%,K2O+Na2O为2.72%~3.38%,属富铁、富碱超基性岩类。该类岩石具有稀土和大离子亲石元素及(^87Sr/^86Sr);值较高的特征,与典型幔源岩石有不同。 相似文献
933.
塔里木盆地克拉2特大型气田流体包裹体特征及油气成藏作用 总被引:18,自引:3,他引:15
储层液体包裹体测试分析是研究油气运移、成藏时间和期次和问题的一种非效的方法,克拉2气田储层流体包裹体类及其丰度统计分析表明,烃类包裹体丰度与储层含油气必一之间具有明显相关性,根据包裹体产状,均一温度和包裹体成分拉曼光谱分析结果发现,油气在成岩早期就开始注入,并一直保存在储层中,直到后期才裂解成干气,有机包裹体均一温度表现为一个主峰,盐水包裹体均一温度有三个区间(峰值),其中第一个峰值与有机包裹体一 相似文献
934.
江苏六合新生代玄武岩中地幔捕虏体的硫化物相研究 总被引:13,自引:3,他引:10
江苏六合一带碱性玄武岩中的出露有以尖晶石二辉橄榄岩为主的地幔捕虏体,这些地幔矿物中普遍有硫化物相出现:(1)被寄主矿物捕获的早期硫化物颗粒。(2)产于矿物晶粒边界或次生裂隙充填物,(3)硫化物包裹体,包括单相硫的包裹体、硫化物-玻璃两相熔体包裹体和CO/2-硫化物-玻璃(含硅酸盐子矿物)的多相包裹体,电子探针分析表明,硫化物包裹体比例隙中硫化物具有更高的相对Fe和S含量,较低的Ni含量。硫化物包裹 相似文献
935.
从井儿洼孔岩心看阳原盆地第四纪湖相层的划分 总被引:10,自引:0,他引:10
通过对阳原盆地中井儿洼孔(深200,6m)河湖相岩石地层、生物地层和古地磁等的研 究,将第四系河湖相层新命名为阳原群,进一步划分3个组,即下更新统8泥河湾组(深200.6~107.8m,未见底),由褐灰色粉砂质粘土和粉砂组成;下一中更新统小组成;下一中更新统小渡口组(深107.8~20.6m)由灰、灰黑色粉砂质粘土和粉砂 质粘土和粉砂组成,内含12段纹层,可作为标志层,底界年龄约1000Ka;中一上更新 相似文献
936.
吕梁地区早前寒武纪主要地质事件的年代框架 总被引:37,自引:1,他引:36
通过同位素地质年代学研究初步建立的吕梁山地区早前寒武纪主要地质事件的年代格架是:界河口群形成在2600~2400Ma期间。吕梁群近周峪组火山岩形成在2360~2350Ma期间,2124Ma时野鸡山群白龙山组火山喷发。赤坚岭杂岩约在2150Ma时侵位,随后发生了钾质花岗岩的侵入(2031Ma左右),界河口群和吕梁山群都爱到这次构造热事件的影响。芦芽山紫苏花岗岩在1800Ma左右侵位。 相似文献
937.
CHENG Yuqi LIU Dunyi I.S. WILLIAMS JIAN Ping ZHUANG Yuxun GAO Tianshan Institute of Geology Chinese Academy of Geological Sciences Barwanzhuang Rd. Beijing China Research School of Earth Sciences Australian National University G.P.O Box Canberr A.C.T. Australia Anhui Geological Survey Changjiangdong Rd. Hefei Anhui China 《《地质学报》英文版》2000,74(4):748-765
The paper reports SHRIMP U-Pb zircon data of a dark eclogite and a post-eclogite garnet-bearing gneissic granitic rock from the Bixiling area, Yuexi County, Anhui Province, in the eastern Dabie Mountains. The eclogite, which is metamorphosed basic tuff, contains very scarce zircons in omphacite or garnet, but more zircons in quartz. They usually exhibit a double-layered texture, as shown clearly in cathodoluminescence images. Their inner main parts give a 206Pb/238U age of 757±7 Ma, representing the approximate age of the high-pressure (HP)- ultrahigh-pressure (UHP) metamorphic event during which the eclogite was formed. The outer peripheral parts of the zircons, which have been modified by late-stage fluids, give an age of 223±3 Ma. The granitic rock contains more zircons of anatectic origin found mostly in feldspar and quartz and usually also showing a similar composite texture. The inner main parts of the anatectic zircons with oscillatory zoning give a 206Pb/238U age of 727±15 Ma for the approxim 相似文献
938.
Rejuvenation of Fossil Sutures and Related Mesozoic Intracontinental Orogenies in South China 总被引:4,自引:0,他引:4
The Huanan (South China) subcontinent was created by amalgamation of the Yangtze, Xianggan, Ca-thaysia and Zhemin microcontinents by the Guangxi orogeny in the Early Palaeozoic. The closure of the Tethyan Ocean and subsequent collision event outside the amalgamated continent reactivated fossil sutures and resulted in in-tracontinental (ensialic) orogenies in the Mesozoic. Based on evidence from deformation, molasse and granitoids, the Sichuan-Guizhou-Hunan-southern Hubei and Hunan-Jiangxi-Fujian Yanshanian fold-thrust systems and the Lower Yangtze-northwestern Fujian Indosinian fold-thrust system are thought to be intracontinental orogens. Their main features are as follows: intracontinental orogenies occurred areally, thrusting propagated towards the interior of the continental, they extend parallelly to the strikes of the fossil sutures, and the details of the temporal-spatial evolution of the orogens depend on subduction-collision events. 相似文献
939.
SUN Yuzhuang Basin Reservoir Research Centre University of Petroleum Shuiku Ro Changping Beijing JIN Yujie China University of Mining Technology Beijing 《《地质学报》英文版》2000,74(1):93-101
Previous studies have shown that the oxidizing brines from the Early Permian Rotliegende sequence have influences on the organic matter of Kupferschiefer. However, inside the Rotliegende sequence there are two other black shales: the Lower and Upper Antracosia shales, which have not been studied as much in detail as in Kupferschiefer. In the present study 12 samples from the Lower and Upper Antracosia shales were analyzed by organic geochemical methods in order to clarify the influences of the oxidizing brines on organic matter. The results indicate that the organic matter of the samples from the Upper Antracosia shale and the bottom of the Lower Antracosia shale was oxidized under the influences of the oxidizing brines. The oxidation resulted in a depletion of saturated hydrocarbons and the alky Is of the aromatic compounds. 相似文献
940.
ZHANG Qiuying Bureau of Geology China National Nuclear Corporation P.O. Box Beijing 《《地质学报》英文版》2000,74(3):602-604
: Black shales are marine sediments with argillaceous, silty and siliceous compositions and high contents of organic materials, disseminated pyrite and uranium. Uraniferous black shale has uranium content of more than 20 ppm.Black shales are widely distributed in 17 provinces or autonomous regions in northwestern and southern-central China. Their sedimentary ages are from the Sinian to the Tertiary and uraniferous black shales are mainly exposed in Yunnan, Guizhou, Sichuan, Hunan, Hubei, Jiangxi, and Zhejiang provinces and Guangxi Zhuang Autonomous Region and the economically significant uranium deposits associated with black shale occur in Hunan and Jiangxi provinces and Guangxi Zhuang Autonomous Region.Uranium mineralization associated with black shale has the following main features: (1) forming stratabound deposits; (2) controlled by structures such as interlayer and intersected faults and fractures; (3) associated with different ore-forming processes such as leaching and hydrothermal reworking; (4) 相似文献