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   250篇
  免费   59篇
  国内免费   9篇
测绘学   38篇
大气科学   4篇
地球物理   225篇
地质学   36篇
海洋学   4篇
天文学   1篇
综合类   4篇
自然地理   6篇
  2023年   2篇
  2022年   10篇
  2021年   7篇
  2020年   14篇
  2019年   21篇
  2018年   18篇
  2017年   12篇
  2016年   12篇
  2015年   10篇
  2014年   12篇
  2013年   14篇
  2012年   22篇
  2011年   20篇
  2010年   10篇
  2009年   15篇
  2008年   15篇
  2007年   14篇
  2006年   16篇
  2005年   17篇
  2004年   9篇
  2003年   14篇
  2002年   10篇
  2001年   4篇
  2000年   5篇
  1999年   3篇
  1998年   2篇
  1997年   2篇
  1996年   6篇
  1992年   1篇
  1991年   1篇
排序方式: 共有318条查询结果,搜索用时 15 毫秒
101.
超高层建筑动态特性监测方法研究   总被引:1,自引:0,他引:1  
围绕超高层建筑动态特性监测方法展开研究,重点解决超高层建筑施工控制网竖向传递倾斜偏差改正这一关键性技术难题。结果表明,数字正垂仪法、CCD法、倾斜仪法均可准确获取超高层建筑的周日摆动规律,为投点时机选择和投点纠偏提供决策支持。  相似文献   
102.
高层隔震结构非线性地震响应分析及设计方法研究   总被引:3,自引:0,他引:3  
高层隔震结构的分析理论和设计方法是目前隔震技术向高层建筑推广的2个关键理论问题。本文以高烈度区宿迁市已经竣工的高层隔震建筑阳光大厦为工程实例,对高层隔震结构的非线性地震响应分析方法进行了研究,包括隔震支座竖向不同拉压刚度的模拟、各种类型的隔震支座水平力学特性的准确模拟,以及不同地震动输入方式和输入角度对隔震支座受拉情况的影响分析等;在此基础上,对隔震层的设计方法进行了分析,提出了隔震层设计的基本原则,进而给出了控制隔震层设计的基本指标,包括隔震支座的长期面压、极值面压、隔震层偏心率等;最后,对高层隔震结构的相关构造要求进行了必要的说明。  相似文献   
103.
用数值模拟方法研究北京盆地对3~10s地震动的放大效应   总被引:1,自引:0,他引:1  
以北京盆地为例,针对不同的设定地震,研究了不同震源条件对盆地放大效应的影响。结果表明:尽管震源因素可对计算结果带来一些不确定性,但盆地内沉积物的厚度是控制3~10 s周期段地震动加速度反应谱的主要因素。因此,计算了盆地对3~10 s周期段地震动加速度反应谱的平均放大系数,并通过回归分析得到了平均放大系数与盆地等效沉积物厚度之间的函数关系。最后,结合北京盆地内高层建筑的分布,初步探讨了高层建筑地震致灾风险水平与盆地结构的关系。  相似文献   
104.
To explore the seismic performance of a high-rise pile cap foundation with riverbed scour, a finite element model for foundations is introduced in the OpenSees finite element framework. In the model, a fiber element is used to simulate the pile shaft, a nonlinear p-y element is used to simulate the soil-pile interaction, and the p-factor method is used to reflect the group effects. A global and local scour model is proposed, in which two parameters, the scour depth of the same row of piles and the difference in the scour depth of the upstream pile and the downstream pile, are included to study the influence of scour on the foundation. Several elasto-plastic static pushover analyses are performed on this finite element model. The analysis results indicate that the seismic capacity (or supply) of the foundation is in the worst condition when the predicted deepest global scout depth is reached, and the capacity becomes larger when the local scour depth is below the predicted deepest global scout depth. Therefore, to evaluate the seismic capacity of a foundation, only the predicted deepest global scout depth should be considered. The method used in this paper can be also applied to foundations with other soil types.  相似文献   
105.
介绍了柳州市某小区高层商住楼各个勘察阶段的岩土工程地质条件,重点通过对基础方案的技术可行性和经济成本两方面对比,探讨了该商住楼地基基础的选型问题,以工程实例告诫地质技术人员从事岩土工程勘察需要注意细节工作。  相似文献   
106.
In this paper, the configuration and working mechanism of the recently developed double spherical seismic isolation (DSSI) bearing are introduced in detail. Then, vertical displacement of the DSSI bearing due to sliding on a spherical surface is analyzed. The results from seismic performance testing of the bearing are given, and a numerical analysis of a four span continuous girder bridge is performed. The numerical analysis compares the influence of three different bearing arrangement schemes on the structural seismic response, and the results show that the DSSI bearing is effective in increasing the vertical load bearing capacity, reducing the vertical displacement, and controlling the energy dissipation capacity within a certain range.  相似文献   
107.
In this paper the rocking response of slender/rigid structures stepping on a viscoelastic foundation is revisited. The study examines in depth the motion of the system with a non‐linear analysis that complements the linear analysis presented in the past by other investigators. The non‐linear formulation combines the fully non‐linear equations of motion together with the impulse‐momentum equations during impacts. The study shows that the response of the rocking block depends on the size, shape and slenderness of the block, the stiffness and damping of the foundation and the energy loss during impact. The effect of the stiffness and damping of the foundation system along with the influence of the coefficient of restitution during impact is presented in rocking spectra in which the peak values of the response are compared with those of the rigid block rocking on a monolithic base. Various trends of the response are identified. For instance, less slender and smaller blocks have a tendency to separate easier, whereas the smaller the angle of slenderness, the less sensitive the response to the flexibility, damping and coefficient of restitution of the foundation. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
108.
本文提出了一种基于叠层橡胶支座的大高宽比高层建筑分段隔震结构形式,并对同一高层建筑结构分别采用基础隔震、层间隔震和分段隔震三种不同形式时进行了数值模拟对比分析。结果表明,采用分段隔震形式可明显减小高层建筑结构的顶层侧向位移、中间隔震层的相对位移和下支柱端应力,使结构的侧向位移集中于两个隔震层上,耗散了大部分地震输入能量,保障了与隔震层相连的构件的安全性,防止了由于支座受拉或剪压破坏导致上部结构倾覆倒塌现象的发生。  相似文献   
109.
Modelling assumptions, boundary and loading conditions have a significant effect on analytical assessment of ductility supply and demand measures for RC bridges, a structural form which had suffered extensively in recent earthquakes. In recognition of the important role played by analysis in advancing seismic design of bridges, this paper is concerned with assessing the effect of model characteristics and earthquake strong-motion selection on analytical action and deformation seismic design parameters. This is of particular significance when viewed in the light of the large capital investment and problems with the satisfaction of dynamic similitude encountered in physical testing of piers and pier-deck assemblies. The models studied range between simple fixed-base cantilever and inclusion of both soil and deck effects, represented by assemblies of springs in translational and rotational degrees of freedom. Moreover, two sets of earthquake records are used in dynamic analysis, each comprising six records covering low, intermediate and high a/v, where a and v are the peak ground acceleration and velocity, respectively. The two sets differ in the scaling procedure employed to bring them to a common level of severity; the first set is obtained by direct acceleration scaling whilst the second utilizes the concept of velocity spectral intensity. The results from static and dynamic analysis, using advanced material characterization and solution procedures, are assessed and discussed. Subject to the limitations of the study, outlined in the paper, the results indicate that the inclusion of deck stiffness and/or soil representation is essential to avail of accurate seismic response parameters. However, the effect of variations in soil stiffness and/or deck torsional rigidity applied in the analysis is rather small, compared to the inclusion/exclusion of the model feature. Moreover, it is also observed that using acceleration scaling leads to much larger scatter in the results than when velocity spectral intensity scaling is used. Finally, the results from two particular earthquakes, Friuli and El Centro, highlight the peril of using a small number of records selected without due consideration to the relationship between their wave form, predominant periods and spectral shapes on the one hand and the response periods of the structure on the other.  相似文献   
110.
混凝土高层建筑结构地震破坏抗毁能力评估   总被引:4,自引:4,他引:0       下载免费PDF全文
许立强 《地震工程学报》2018,40(1):14-19,47
提出基于构件性能的混凝土高层建筑结构地震破坏抗毁能力评估方法,采用强度与延性法分析混凝土高层建筑构件强度和变形,以对强震作用下混凝土高层建筑结构性能实施准确描述。基于建筑结构性能以及多条地震波情况下高层建筑结构倒塌极限状态的分析规范,采用IDA方法设置建筑结构抗倒塌能力系数,并依据该系数获取基于构件性能的混凝土高层建筑结构地震破坏抗毁能力评估流程,实现建筑结构地震破坏抗毁能力的准确评估。实验结果说明,所提方法实现了混凝土高层建筑结构地震破坏抗毁能力的准确评估。  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