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991.
西部凹陷南部沙三段储层沉积特征及含油气性分析 总被引:12,自引:9,他引:12
西部凹陷南部为辽河油田的重点探区之一,具有十分优越的石油地质条件。本区在沙三期断陷活动强烈,发育了巨厚的深水泥岩和多期次缓坡型湖底扇沉积,为油气聚集成藏提供了丰富的油气源条件和储集条件。沙三段沉积时期,在西部凹陷南部发育有齐家-杜家台和锦州-欢喜岭两大湖底扇沉积体系。受物源区的距离、基底构造和主干断层活动的控制,湖底扇平面上具有分带性,可划分为内扇、中扇和外扇三个亚相带。齐杜和锦欢湖底扇在沙三早期规模较小,中期规模最大,晚期萎缩。本区沙三段储层物性普遍较差,以低孔-低渗、特低孔-特低渗储层为主,其中湖底扇中扇辫状沟道微相砂体储集性能最好,平面上依中扇辫状沟道→中扇前缘→外扇亚相储层物性由好变差。储集性能的优劣主要受母岩区岩性、沉积作用、成岩作用等多种因素控制。沙三段湖底扇砂体在区内分布广泛,处于成熟生油岩的包围之中,位于油气运移的有利指向上,成藏条件优越,勘探前景广阔。 相似文献
992.
跨入新世纪 迎接新挑战 总被引:1,自引:0,他引:1
本文分析了21世纪铀矿地质科研面临的新形势,提出今后工作的总体方针是认真贯彻中央精神,具体落实中核集团提出的目标任务,在成矿理论的创新与发展,传统与非传统矿产资源的勘查与开发利用,矿业开发与环境保护的协调发展等研究领域有新的突破。文章强调了大规模成矿作用及大型矿集区预测研究的重要性,认为应加强学科交叉和学术交流活动,争取良好的政策环境,保持必要的投资强度,培养和造就一批年轻的技术骨干和学科带头人,以崭新的姿态迎接21世纪的挑战。 相似文献
993.
A LINEAR THEORY FOR DISTURBANCE OF COHERENT STRUCTURE AND MECHANISM OF SAND WAVES IN OPEN-CHANNEL FLOW 总被引:3,自引:0,他引:3
Yuchuan BAI Andreas MALCHEREK Changbo JIANG Institute for Sedimentation on River Coast Engineering Tianjin University Tianjin China. E-Mail: Ychbai@tiu.edu.cn Federal Waterways Engineering Research Institute 《国际泥沙研究》2001,16(2)
1 INTRODUCTIONT'he early theory for tUrbulent boundare layer assumed that the now adjacent to the wall is a lndnar innature and is named lndnar bottom layer Its thickness is about V/u*, Where V is the ldnehc viscosityand u* is the fuchon velocity. Towmsend (l956) first suggested the concePt of tUrbulent strUctUre andpointod out that there are isotroPic small scale nuctUation and quasi-periodic large scale strUcture in theshear flow Einstein and Li (l956) discovered by the flow moving… 相似文献
994.
VELOCITY PROFILES OF TURBULENT OPEN CHANNEL FLOWS 总被引:1,自引:0,他引:1
WANG Dianchang WANG Xingkui YU Mingzhong LI Danxun Doctor Prof Dept. of Hydraulic Engineering Tsinghua University Beijing China 《国际泥沙研究》2001,16(1)
1 INTRODUCTIONThe vertical velocity profile of open channel flows is the most basic infOrmation for the stUdy of flowresistance, channel bed stability, river nuvial process and sediment transport. Although it has been asubject of great interest for many years, there does not exist a consensus on some perPlexing questions,such as the position of the theoretical bed level. In order to investigate the properties of velocity profile,data measured in open channel nows from eight sources were … 相似文献
995.
The impact of wastewater flow on the channel bed morphology was evaluated in four ephemeral streams in Israel and the Palestinian Territories: Nahal Og, Nahal Kidron, Nahal Qeult and Nahal Hebron. Channel changes before, during and after the halting of wastewater flow were monitored. The wastewater flow causes a shift from a dry ephemeral channel with intermittent floods to a continuous flow pattern similar to that of humid areas. Within a few months, nutrient‐rich wastewater flow leads to rapid development of vegetation along channel and bars. The colonization of part of the active channel by vegetation increases flow resistance as well as bank and bed stability, and limits sediment availability from bars and other sediment stores along the channels. In some cases the established vegetation covers the entire channel width and halts the transport of bed material along the channel. During low and medium size flood events, bars remain stable and the vegetation intact. Extreme events destroy the vegetation and activate the bars. The wastewater flow results in the development of new small bars, which are usually destroyed by flood flows. Due to the vegetation establishment, the active channel width decreases by up to 700 per cent. The deposition of fine sediment and organic material changed the sediment texture within the stable bar surface and the whole bed surface texture in Nahal Hebron. The recovery of Nahal Og after the halting of the wastewater flow was relatively fast; within two flood seasons the channel almost returned to pre‐wastewater characteristics. The results of the study could be used to indicate what would happen if wastewater flows were introduced along natural desert streams. Also, the results could be used to predict the consequences of vegetation removal as a result of human intervention within the active channel of humid streams. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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流动型态对曼宁糙率系数的影响研究 总被引:7,自引:0,他引:7
根据明渠水流流动型态的概念,通过对实验资料的分析,得到均匀流时糙率系数随水深增加而减小,形成M1型水面线的非均匀流时糙率系数随水深、水力坡度的增大而增大的规律。提出的糙率系数的二步计算法,可以解决因非均匀流水深沿程变化,难以建立糙率系数与水深关系的困难,为在水力计算中修正糙率系数提供了依据。 相似文献
1000.