全文获取类型
收费全文 | 16879篇 |
免费 | 4133篇 |
国内免费 | 4659篇 |
专业分类
测绘学 | 313篇 |
大气科学 | 20篇 |
地球物理 | 3843篇 |
地质学 | 19188篇 |
海洋学 | 851篇 |
天文学 | 6篇 |
综合类 | 1186篇 |
自然地理 | 264篇 |
出版年
2024年 | 133篇 |
2023年 | 489篇 |
2022年 | 736篇 |
2021年 | 732篇 |
2020年 | 571篇 |
2019年 | 688篇 |
2018年 | 485篇 |
2017年 | 564篇 |
2016年 | 603篇 |
2015年 | 701篇 |
2014年 | 1048篇 |
2013年 | 813篇 |
2012年 | 1021篇 |
2011年 | 971篇 |
2010年 | 809篇 |
2009年 | 880篇 |
2008年 | 926篇 |
2007年 | 741篇 |
2006年 | 801篇 |
2005年 | 675篇 |
2004年 | 790篇 |
2003年 | 767篇 |
2002年 | 806篇 |
2001年 | 844篇 |
2000年 | 742篇 |
1999年 | 768篇 |
1998年 | 751篇 |
1997年 | 712篇 |
1996年 | 725篇 |
1995年 | 715篇 |
1994年 | 670篇 |
1993年 | 576篇 |
1992年 | 608篇 |
1991年 | 522篇 |
1990年 | 479篇 |
1989年 | 386篇 |
1988年 | 88篇 |
1987年 | 84篇 |
1986年 | 43篇 |
1985年 | 33篇 |
1984年 | 21篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 17篇 |
1980年 | 17篇 |
1979年 | 24篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1954年 | 7篇 |
1948年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
982.
《国务院关于支持福建省加快建设海峡西岸经济区的若干意见》出台后,福建省煤田地质局随即出台了18条贯彻实施意见,提出要努力实现地质找矿的重大突破,“十一五”期间,提交煤炭资源储量2.8亿t以上,超额完成提交2.2亿t的目标任务;“十二五”期间,提交煤炭资源储量2.5亿t以上; 相似文献
983.
On tectonic movement in the South China Sea during the Cenozoic 总被引:1,自引:1,他引:0
The tectonic movement taking place at the end of Cretaceous and the beginning of Cenozoic had opened the Cenozoic phase of polycyclic tectonic movements, then the whole crust of the South China Sea had been mainly subjected to the regional stress field of tectonic tension, which was characterized by rifting depression. Seven times of regional tectonic movement and sedimentation had been assembled into a geological development history of polycyclic oscillation. Especially, the tectonic movements were strongly intensified at the end of Cretacious and the beginning of Paleagene, between Late Eocene and MidOligocene, during Mid and Late Miocene. These three times of tectonic movement had built the most important regional tectonic interfaces in the South China Sea. Crust movements of the South China Sea were the result and epitome of interaction of the Eurasia, Pacific and IndoAustralia plates, that is, they were introduced by polycyclic changes of directions, rates and strengths of lithospheric movements and asthenospheric flows across the Pacific and IndoAustralia plates. 相似文献
984.
南海北部神狐海域天然气水合物形成及分布的地质因素 总被引:6,自引:0,他引:6
从天然气水合物发育的地质构造条件、沉积条件、气源条件、温压条件等分析了神狐海域影响水合物形成及分布的地质因素.指出神狐海域处在洋陆壳的过渡带上,断裂-褶皱构造及流体底辟构造发育,对水合物的形成具有重要的控制作用.受等深流和海底滑塌双重作用,研究区沉积异常体发育,沉积厚度大、沉积速率高,有利于水合物发育.通过对神狐海域附近钻探结果及区内地质调查站位资料的分析表明:目标区具有含巨量的生物气和热成因气资源潜力,具备形成天然气水合物的气源条件,气源为文昌-恩平组烃源岩.此外,受热流值北高南低的分布格局的影响,神狐海域BSR埋深也表现为北部浅南部深,且BSR分布区整体处在天然气水合物稳定存在的温压范围内,满足水合物形成及保存所需的温压条件.神狐海域的地质构造条件、沉积特征、气源条件、温压条件等都非常有利于天然气水合物发育. 相似文献
985.
HUANG Yulong WANG Pujun CHEN Shuming .College of Earth Sciences Jilin University Changchun China.Daqing Oilfield Corporation PetroChina Daqing Heilongjiang China 《东北亚地学研究》2009,12(2):64-79
About forty productive oil/gas fields hosted in volcanic reservoirs have been found since 1957 in fourteen basins of China. They can be simply subdivided into two groups, the east and the west. Reservoir volcanic rocks of the east group are predominantly composed of Late Jurassic to Early Cretaceous rhyolite and Tertiary basalt, preferred being considered as rift type volcanics developed in the circum-Pacific tectonic regime. Those of the west are Permo-Carboniferous intermediate/basic volcanic rocks, being island-arc type ones developed in paleo-Asian Ocean tectonic regime. 相似文献
986.
Since Late Proterozoic era, the Korean Peninsula has been evolved into a state with relatively stable regions and orogenic belts which were developed differently each other. The Late Paleozoie (Late Carboniferous-Early Triassic) sediments are well developed in the Korean Peninsula, and called the Pyongan System. The Pyongan System from Late Carboniferous to Lower Triassic is distributed in the Pyongnan and Hyesan-Riwon Basins, and Rangrim Massif, and divided into Hongjom ( C2 ), Ripsok ( C2 ), Sadong ( C2-P1 ), Kobangsan and Rokam (Taezhawon) (P2-T1) sequences. The sediments of the Tumangang Orogenic Belt are called Tuman System which is composed of the Amgi Series, consisting of elastic formation with mafic effusive material, overlaid by the Kyeryongsan Series, consisting mainly of marie volcano sediments. The Songsang Series which rests on the Kyeryongsan Series mainly consists of elastic formation with minor felsic effusive material. In the Tumangang Orogenic Belt the tectonic movement, called Tumangang Tectonic Movement, occurred in the Lower Permian-Lower Triassic. 相似文献
987.
Based on a synthesis of zircon inheritance from Mesozoic igneous rocks in the eastern portion of the North China Craton (NCC) , it is proposed that inherited zircons with Neoproterozoie ages identified from these rocks are of a heterogenous derivation from the Yangtze/South China block, rather than from the NCC itself. The mechanism that introduces these zircons incorporated into the NCC is likely by tectonic underplating during the Triassic continental subduction of the Yangtze block beneath the NCC. Tectonic addition of abundant crustal materials represented by the heterogenous zircons into the NCC, probably along Moho or weak interfaces within the NCC's crust, led to the crustal thickening in the NCC. These heterogenous materials, either as (partial) source rocks or as contaminants of the magmas generated during an extension environment following the crustal thickening, were reworked and therefore have significant contribution to petrogenesis of the Mesozoic igneous rocks. The crustal thickening resulted from the tectonic underplating, as indicated by the distribution extent of the heterogenous zircons, is spatially similar to that of the lithospheric thinning, with both mainly occurring in the eastern segment of the NCC. This is probably suggestive of an intrinsic relation between the thickening and thinning events during the Mesozoic evolution of the NCC. 相似文献
988.
PANG Jungang LI Wenhou XIAO Li. School of Petroleum Resources Xi'an Shiyou University Xi'an China. Geological Department Northwest University Xi'an China. State Key Laboratory of Continental Dynamics China. Geological Research Institute of Shengli Oilfield Co. Ltd. SINOPEC Dongying Sh ong China 《东北亚地学研究》2009,(4):183-188
Lacustrine turbidite of Chang-7 Member in the studied area consists of sihstone and fine sandstone with respect to grain size, which is feldspathic lithie sandstone, syrosem arkose and arkose with respect to mineral constitution affected by provenance. There are such apparent signatures as lithology, sedimentary structure, sedimentary sequence and well logs, to recognize turbidite. During the paleogeographic evolution of Chang-7 Member, lake basin and deep lake are both at their maximum extent during Chang-73 stage, resulting in the deposition of Zhangjiatan shale with widespread extent and of turbidite with fragmental-like. Deep lake line is gradually moving toward lake center and turbidite sand bodies are gradually turning better with better lateral continuity, connectivity and more thickness, from stages of Chang-73, Chang-72 and Chang-7t, which can be favorable reservoir in deep-water. 相似文献
989.
探索热液矿床成矿作用的方向性,是勘查矿床和寻找盲矿体时,一个迫切需要解决的研究课题.早在20世纪80年代,中国地矿界便面临寻找隐伏矿、半隐伏矿的挑战,就需要开展"区域成矿作用方向性的理论找矿",以已知预测未知. 相似文献
990.
耿达短水准异常与汶川8.0级地震 总被引:2,自引:1,他引:1
结合龙门山断裂带其他跨断层资料,对耿达短水准在汶川8.0级地震前后的观测资料进行了重新分析,发现耿达短水准在汶川地震前后的异常为当地居民修建生活小区所致,不应视为地震前兆异常。 相似文献