全文获取类型
收费全文 | 5045篇 |
免费 | 849篇 |
国内免费 | 1042篇 |
专业分类
测绘学 | 782篇 |
大气科学 | 646篇 |
地球物理 | 737篇 |
地质学 | 2725篇 |
海洋学 | 495篇 |
天文学 | 5篇 |
综合类 | 502篇 |
自然地理 | 1044篇 |
出版年
2024年 | 36篇 |
2023年 | 73篇 |
2022年 | 207篇 |
2021年 | 269篇 |
2020年 | 232篇 |
2019年 | 260篇 |
2018年 | 187篇 |
2017年 | 248篇 |
2016年 | 262篇 |
2015年 | 277篇 |
2014年 | 354篇 |
2013年 | 322篇 |
2012年 | 386篇 |
2011年 | 411篇 |
2010年 | 317篇 |
2009年 | 344篇 |
2008年 | 347篇 |
2007年 | 361篇 |
2006年 | 306篇 |
2005年 | 256篇 |
2004年 | 221篇 |
2003年 | 180篇 |
2002年 | 166篇 |
2001年 | 172篇 |
2000年 | 128篇 |
1999年 | 107篇 |
1998年 | 111篇 |
1997年 | 100篇 |
1996年 | 67篇 |
1995年 | 54篇 |
1994年 | 45篇 |
1993年 | 36篇 |
1992年 | 38篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有6936条查询结果,搜索用时 62 毫秒
991.
992.
993.
This paper proposes bi‐directional coupled tuned mass dampers (BiCTMDs) for the seismic response control of two‐way asymmetric‐plan buildings subjected to bi‐directional ground motions. The proposed BiCTMD was developed from the three‐degree‐of‐freedom modal system, which represents the vibration mode of a two‐way asymmetric‐plan building. The performance of the proposed BiCTMD for the seismic response control of elastic two‐way asymmetric‐plan buildings was verified by investigating the reductions of the amplitudes of the associated frequency response functions. In addition, the investigation showed that the proposed BiCTMD is effective in reducing the seismic damage of inelastic asymmetric‐plan buildings. Therefore, the BiCTMD is an effective approach for the seismic response control of both elastic and inelastic two‐way asymmetric‐plan buildings. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
994.
995.
针对大跨度空间结构楼板振动舒适度问题,建立相应的人-板耦合模型,通过理论分析及有限元计算,系统研究了人-板相互作用体系的动力特性.详细分析了板的约束条件、楼板装饰层以及人群荷载密度分布等各种因素对楼板自振特性的影响.以大跨度车站结构为背景,采用人-板耦合体系,进行人行荷载同步、队列、散步等不同方式作用下楼板竖向振动的研... 相似文献
996.
Evaluation model of landslide hazards induced by the 2008 Wenchuan earthquake using strong motion data 总被引:1,自引:0,他引:1
Xiuying Wang Gaozhong Nie Mujun Ma Institute of Crustal Dynamics China Earthquake Administration Beijing China Institute of Geology Beijing China National Earthquake Response Support Service Beijing China 《地震学报(英文版)》2011,(3):311-319
Landslides induced by the 2008 Wenchuan earthquake in the Longmenshan area were relatively well instrumented,which makes it possible to investigate the landslides using ground motion records.Firstly,this paper analyzes the data from Wenchuan earthquake on both regional and local site scale.The analyses show that the Newmark accumulative displacement calculated from the ground motion recorded in a particular geological hazard zone corresponds to the hazard intensity in that zone;the larger the displacemen... 相似文献
997.
This paper summarizes the relevant results of the design, construction, testing, and implementation of a nominal 120 kN magnetorheological damper developed to control a free‐plan tall building in Santiago, Chile, equipped with two 160‐ton tuned masses. Cyclic as well as hybrid simulation tests were performed on the prototype damper. Global building responses using measured MR properties showed good correlation with analytical estimations. Also, a proposed physical controller for the MR damper was validated through hybrid and building pull‐back tests. Its performance is essentially equivalent to that of an LQR controller, but the information needed in its implementation is considerably less. Pull‐back tests of 10 cm amplitude were performed on one mass along the flexible edge of the building and its response controlled using the passive and controlled modes of the MR damper. The MR damper was capable of controlling the TM displacements very effectively, as well as the simulated building response for different ground motions and harmonic excitation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
998.
999.
1000.
21个气候模式对东亚夏季环流模拟的评估II:年际变化 总被引:4,自引:2,他引:2
利用欧洲中期天气预报中心的ERA40再分析资料, 评估了参与政府间气候变化专门委员会第四次评估报告的21个全球海气耦合模式对东亚地区夏季大气环流年际变率的模拟能力,结果表明:(1)模式对东亚地区不同要素的年际变率模拟能力整体偏弱, 500 hPa高度场的模拟能力总体优于海平面气压场及850 hPa风场;(2)两大环流系统年际变率的模拟结果评估表明:就相关系数而言,副高强度、面积的模拟能力优于印度低压,多数模式能正确模拟出副高1970s后期增强的趋势;就标准差来看,模式对印度低压、印度低压东伸槽模拟效果相对较好;(3)评估三种季风指数的模拟能力结果显示,环流异常指数模拟效果略好,但多数模式都不能模拟出海陆气压差、经向风、环流异常季风指数的年际变化。 相似文献