首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   78篇
  免费   17篇
  国内免费   1篇
测绘学   3篇
大气科学   2篇
地球物理   55篇
地质学   17篇
海洋学   9篇
天文学   5篇
综合类   5篇
  2021年   1篇
  2020年   2篇
  2018年   4篇
  2017年   4篇
  2016年   4篇
  2015年   6篇
  2014年   6篇
  2013年   3篇
  2012年   5篇
  2011年   6篇
  2010年   6篇
  2009年   7篇
  2008年   6篇
  2007年   5篇
  2006年   7篇
  2005年   2篇
  2004年   4篇
  2003年   3篇
  2002年   4篇
  2001年   3篇
  2000年   1篇
  1999年   2篇
  1997年   2篇
  1994年   1篇
  1993年   1篇
  1985年   1篇
排序方式: 共有96条查询结果,搜索用时 15 毫秒
91.
A series of pseudo‐dynamic tests (PDTs) of a full‐scale 3‐story 3‐bay buckling‐restrained braced frame (BRBF) using concrete‐filled tube columns was tested in the Taiwan National Center for Research on Earthquake Engineering using networked PDT techniques in October 2003. During the tests, real‐time experimental responses and video were webcasted to Internet viewers. The input ground motions adopted for the PDTs were chosen from the 1999 Chi‐Chi and the 1989 Loma Prieta earthquakes and scaled to represent three seismic hazard levels. This paper is in two parts, focusing on the investigations of the overall structure and the local members. This paper constitutes Part I and discusses the design, analytical investigations, and key experimental results of the specimen frame, such as the buckling of the brace‐to‐gusset joints. Part II of the paper, the companion paper, describes the gusset stiffening schemes and detailed experimental behavior of the BRBs and their connections. Experimental peak inter‐story drifts of 0.019 and 0.023 radians, prescribed for the design basis and the maximum credible earthquakes, respectively, are within the target design limits of 0.020 and 0.025 radians. These tests confirmed that the PISA3D and OpenSees nonlinear structural analysis computer programs can simulate the experimental peak shears and floor displacements well. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
92.
A comparison of the diurnal and seasonal variations in the ionospheric equivalent slab thickness (τ) and bottomside slab thickness (B0) is presented based on the observation during high solar activities at a mid-latitude station—Wuhan (114.4°E, 30.6°N). The investigated data include foF2, hmF2, B0, B1, and TEC, and are derived from the measured ionogram and GPS receiver over Wuhan from April 1999 to March 2000. The results show that τ and B0 are highly/weakly correlated during the day/night, respectively. Furthermore, a comprehensive discussion of the relation between τ, B0, and hmF2 for geomagnetic storm events is provided in this paper.  相似文献   
93.
This paper covers the blast-resistant analysis for a tunnel passing beneath Taipei Shongsan airport. It briefly discusses the overall analysis process to obtain the maximum lining thrust caused by a bomb explosion for use in the structural lining design. Because there have not been any established common standards or practices governing the design of such a structure, a series of parametric studies have been carried out in order to evaluate the significance and sensitivity of several parameters on the lining thrust. The parameters evaluated are: intensity of blast loading, size of crater, dynamic undrained shear strength, dynamic Young’s modulus, and soil-damping ratio. It was concluded that a designer should adopt dynamic soil parameters, obtained from good ground investigation and soil testing, as favorable dynamic soil properties can result in a more economical analysis. For parameters (e.g. bomb type) that are beyond the control of the designer, an additional protective layer over the tunnel structure may be considered in order to minimize the impact of the explosion, instead of designing a more costly rigid structure.  相似文献   
94.
95.
Special concentrically braced frames (SCBFs) are commonly used as the lateral‐load resisting system in buildings. SCBFs primarily sustain large deformation demands through inelastic action in the brace, including compression buckling and tension yielding; secondary yielding may occur in the gusset plate and framing elements. The preferred failure mode is brace fracture. Yielding, buckling, and fracture behavior results in highly nonlinear behavior and accurate analytical modeling of these frames is required. Prior research has shown that continuum models are capable of this level of simulation. However, those models are not suitable for structural engineering practice. To enable the use of accurate yet practical nonlinear models, a research study was undertaken to investigate modeling parameters for line‐element models, which is a more practical modeling approach. This portion of the study focused on methods to predict brace fracture. A fracture modeling approach simulated the nonlinear, cyclic response of SCBFs by correlating onset of fracture to the maximum strain range in the brace. The model accounts for important brace design parameters including slenderness, compactness, and yield strength. Fracture data from over 40 tests was used to calibrate the model and included single‐brace component, single story frame, and full‐scale multistory frame specimens. The proposed fracture model is more accurate and simpler than other, previously proposed models. As a result, the proposed model is an ideal candidate for practical performance simulation of SCBFs. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
96.
Hazard assessment model for debris flow prediction   总被引:4,自引:3,他引:1  
Debris flow disasters have plagued Taiwan in recent decades, and caused casualties and destruction of property. Several methods, including the numerical method, statistical method, and experimental method, have been adopted in recent years to predict debris flow, and more recently, the neural network (NN) and the genetic algorithm (GA) methods have been introduced to simulate the occurrence of debris flows. This study proposes using the GA to weigh seven important variables according to principles similar to natural selection. The study then simultaneously inputs these variables into a NN model to predict debris flow occurrences based on relevant factors. There were 154 potential cases of debris flow collected from eastern Taiwan and fed into the model for testing. The average ratio of successful prediction reached 94.94%, which demonstrates that the proposed model can provide stable and reliable results for predicting debris flow in hazard mitigation and guard systems.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号