全文获取类型
收费全文 | 226篇 |
免费 | 72篇 |
国内免费 | 14篇 |
专业分类
测绘学 | 8篇 |
大气科学 | 6篇 |
地球物理 | 172篇 |
地质学 | 97篇 |
海洋学 | 15篇 |
天文学 | 5篇 |
综合类 | 4篇 |
自然地理 | 5篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 15篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 8篇 |
2012年 | 14篇 |
2011年 | 6篇 |
2010年 | 6篇 |
2009年 | 17篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 15篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1986年 | 1篇 |
1978年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有312条查询结果,搜索用时 15 毫秒
91.
通过对博罗可努断裂精河—阿拉山口段微地貌的实地调查 ,发现该断裂错断精河东南到阿拉山口之间的晚更新世冲洪积扇 ,地表留下了冲沟和山脊同步右旋位错、断层陡坎、断层鼓包、拉分盆地等与断层活动有关的微地貌。精河东南冲洪积扇上大冲沟的最大右旋位移为 50 0m ,平均4 0 0m。断层陡坎上的纹沟右旋位移为 2 6~ 4 0m ,较大级别的纹沟位移可分为 5 7m ,8 3m和 15 3m3组。它们大致为 3的整数倍。实测断层陡坎的高度分别为 1 2m ,2 51m和 3 6 3m ,大致是 1 2的整数倍 ,阿拉山口西南断层的水平位移为 1~ 1 7m ;垂直位移可分为两组 ,一组为 0 55m ,另一组为 1 2~ 1 5m。这些数据可能揭示了该断裂段的特征地震水平位移为 3m ,垂直位移为 1 2m。区域地貌对比和年代学分析得出 ,精河东南冲洪积扇的最后形成时代为距今 7万a左右 ,右旋滑动速率为4 7mm/a。 相似文献
92.
The I ingwu fault is in the eastern boundary of the southern section of Yinchuan graben. It hasa close relation to seismicity in the Lingwu-Wuzhong region.Few researches have been done.In this Paper,on the basis of tee data obtained from field investigation,the activity features inLate Quaternary have been discussed.The vertical displacement and its slip rate have been alsoestimated.The fault is 48km in length,being divided into 3 segments according to geologicaland topographical characteristics.The last rupture along its northern and middle segments wasoccurred in late of Late Pleistocene or early Holocene while that along the southern segmentwas occurred in midle Holocene.The vertical slip rate is estimated as 0.23~025mm/a sinceabout 66ka B.P.based on the vertical displacements of terracesⅠ,Ⅱ and Ⅲ and their ages. 相似文献
93.
利用干酷根镜质体反射率等多项指标分析了吐哈盆地杜家台构造侏罗系生油岩的热演化特性,认为该构造上生油岩生油门际在3560m左右。侏罗系七克台组、三间房组、三工河组的生油岩处于未成熟阶段,西山窑组和八道湾组也尚进入生油阶段。八道湾组煤系地层成熟度高,是入亮煤阶段,煤成气生成量多,是重点勘探层。 相似文献
94.
重组鱼类生长激素对中国对虾成活率及促生长作用的研究 总被引:2,自引:0,他引:2
11999933年年后后暴暴发发性性对对虾虾病病毒毒病病的的流流行行 ,,严严重重制制约约着着对对虾虾养养殖殖的的进进一一步步发发展展。。如如何何通通过过促促进进中中国国对对虾虾生生长长 ,,提提高高其其抗抗病病力力已已成成为为目目前前亟亟待待解解决决的的问问题题 ;;其其中中通通过过在在对对虾虾人人工工饵饵料料中中加加入入一一些些生生长长因因子子 ( (如如生生长长激激素素等等 ))或或满满足足对对虾虾的的各各种种营营养养需需求求 ,,提提高高中中国国对对虾虾的的生生长长速速度度与与抗抗病病力力是是解解决决这这… 相似文献
95.
96.
97.
Estimation of Longshore Sediment Transport Rate for a Typical Pocket Beach Along West Coast of India
Estimation of Longshore Sediment Transport Rate (LSTR) in the littoral zone is essential for managing and developing any coastal zone. Numerical models are powerful tool to understand and investigate various processes responsible for LSTR in a systematic manner since direct measurement of LSTR is a difficult task. A one dimensional LITDRIFT model was implemented along the Vengurla coast for estimation of LSTR and to analyze the sensitivity of each input parameters towards the computation of LSTR. Major input parameters required for the estimation of LSTR are nearshore wave climate, bathymetry, and sediment characteristics. The nearshore wave data at a depth of 15 m were collected using wave rider buoy in 2015 is used in the present study. Field observations were carried out to survey the regional bathymetry and sediment characteristics. Annual net LSTR along Vengurala coast is relatively less and varies from ?7778 to ?9015 m3 with an average of ?8511 m3. The net direction of LSTR is towards south and gross LSTR is 1.18 × 105 m3/year. The LSTR reveals more sensitivity to coastline orientation and wave direction. A 1° changes in coastline angle and wave direction causes approximately 3000 m3/month difference in LSTR. Moreover, wave height, wave period, and bed roughness has an important role for controlling LSTR. The model results help to identify the role of each parameter contributing towards LSTR estimation and a similar model approach can be applied to other coasts for estimating LSTR in an accurate way. 相似文献
98.
99.
2021年5月22日青海玛多MW7.4地震作为发生在巴颜喀拉块体内部的一次强震,再次引起了人们对该地区地震活动性的强烈关注.本文基于震后GNSS流动观测和区域连续GNSS站资料,解算了106个站点的同震形变及其中17个站点的高频形变波形.同震形变场显示玛多地震具有典型的左旋走滑特征,GNSS观测到的最大同震位移达到1.2 m.GNSS与InSAR数据相符度较高,GNSS提供了准确的近场形变信息.基于GNSS同震形变场,本文反演了断层滑动分布,并计算了发震断层上产生的库仑应力变化.结果表明,发震断层的滑动破裂存在多个凹凸体,破裂分段特征明显且出露地表,与野外地表破裂考察和余震分布吻合,主体破裂位于断层面0~10 km的浅部区域,最大滑动量达到4.6 m,地震矩1.63×1020N·m,矩震级为MW7.4;发震断层上静态库仑应力增加区域与余震分布具有一致性,说明余震主要是由静态库仑应力加载而触发的. 相似文献
100.
Sheath folds are highly non-cylindrical structures often associated with shear zones. We investigate the formation of sheath folds around a weak inclusion acting as a slip surface in simple shear by means of an analytical model. We present results for different slip surface orientations and shapes. Cross-sections perpendicular to the shear direction through the sheath fold display closed contours, so called eye-structures. The aspect ratio of the outermost closed contour is strongly dependent on the initial slip surface configuration. The center of the eye-structure is subject to change in height with respect to the upper edge of the outermost closed contour for different cross-sections perpendicular to the shear direction. This results in a large variability in layer thickness across the sheath fold length, questioning the usefulness of eye-structures as shear sense indicators. The location of the center of the eye structure is largely invariant to the initial configurations of the slip surface as well as to strain. The values of the aspect ratios of the closed contours within the eye-pattern are dependent on the strain and the cross-section location. The ratio (R′) of the aspect ratios of the outermost closed contour (Ryz) and the innermost closed contour (Ry′z′) shows values above and below 1. R′ shows dependence on the slip surface shape and orientation but not on the number of involved contours. Using R′ measurements to deduce the bulk strain type may be erroneous. 相似文献