全文获取类型
收费全文 | 850篇 |
免费 | 206篇 |
国内免费 | 91篇 |
专业分类
测绘学 | 116篇 |
大气科学 | 19篇 |
地球物理 | 647篇 |
地质学 | 246篇 |
海洋学 | 74篇 |
综合类 | 28篇 |
自然地理 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 10篇 |
2022年 | 38篇 |
2021年 | 32篇 |
2020年 | 60篇 |
2019年 | 54篇 |
2018年 | 29篇 |
2017年 | 31篇 |
2016年 | 28篇 |
2015年 | 25篇 |
2014年 | 46篇 |
2013年 | 45篇 |
2012年 | 52篇 |
2011年 | 68篇 |
2010年 | 75篇 |
2009年 | 62篇 |
2008年 | 44篇 |
2007年 | 65篇 |
2006年 | 89篇 |
2005年 | 50篇 |
2004年 | 48篇 |
2003年 | 42篇 |
2002年 | 37篇 |
2001年 | 34篇 |
2000年 | 15篇 |
1999年 | 16篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
排序方式: 共有1147条查询结果,搜索用时 46 毫秒
51.
Fragility curves express the probability of structural damage due to earthquakes as a function of ground motion indices, e.g., PGA, PGV. Based on the actual damage data of highway bridges from the 1995 Hyogoken‐Nanbu (Kobe) earthquake, a set of empirical fragility curves was constructed. However, the type of structure, structural performance (static and dynamic) and variation of input ground motion were not considered to construct the empirical fragility curves. In this study, an analytical approach was adopted to construct fragility curves for highway bridge piers of specific bridges. A typical bridge structure was considered and its piers were designed according to the seismic design codes in Japan. Using the strong motion records from Japan and the United States, non‐linear dynamic response analyses were performed, and the damage indices for the bridge piers were obtained. Using the damage indices and ground motion indices, fragility curves for the bridge piers were constructed assuming a lognormal distribution. The analytical fragility curves were compared with the empirical ones. The proposed approach may be used in constructing the fragility curves for highway bridge structures. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
52.
第二亚欧大陆桥已成为国际社会关注的焦点之一,但各国对其走向有着不同的见解和主张。本文概述了第二亚欧大陆桥各种走向的有关问题,并强调对其沿线环境灾害必须重视加以治理。 相似文献
53.
本文通过总结多年来桥梁工程勘察的实践经验,针对上海地区的工程地质特点,建造桥梁对勘察的要求,对桥梁墩、台基础型式,基础持力层的选择,地基土特性,勘察方法,土工试验项目的确定,勘察报告的编写等作了分析,论述 。 相似文献
54.
以HDR隔震梁桥多自由度(MDOF)模型和等效双线性单自由度(SDOF)模型为研究对象,以典型近场地震动作为输入,研究HDR支座双向耦合效应对HDR隔震梁桥地震响应的影响。研究结果表明:不考虑双向耦合效应的HDR支座滞回曲线呈典型双线性;考虑双向耦合效应的HDR支座滞回曲线面积小于不考虑双向耦合效应的HDR支座滞回曲线面积。不考虑双向耦合效应的顺桥向HDR支座位移峰值db大于考虑双向耦合效应时,但横桥向的结果相反。近场地震作用下,对梁桥进行HDR支座隔震设计时,忽略双向耦合效应计算得到的墩底剪力峰值和弯矩峰值均偏于保守。可忽略HDR支座双向耦合效应对HDR隔震梁桥近场地震能量的影响。 相似文献
55.
The objective of this paper is to describe the lessons learned and actions that have been taken related to the seismic design
of bridge structures after the Chi-Chi, Taiwan earthquake. Much variable near-fault ground motion data was collected from
the rupture of Chelungpu fault during the Chi-Chi earthquake, allowing the seismic response of bridge structures subjected
to these near-fault ground motions to be carefully examined. To study the near-fault ground motion effect on bridge seismic
design codes, a two-level seismic design of bridge structures was developed and implemented. This design code reflects the
near-fault factors in the seismic design forces. Finally, a risk assessment methodology, based on bridge vulnerability, is
also developed to assist in decisions for reducing seismic risk due to failure of bridges.
Director of Center for Research on Earthquake Engineering.
Supported by: the Science Council, Chinese Taipei, under grant no. SC 90-2211-E-002-028. 相似文献
56.
Limitations associated with deterministic methods to quantify demands and develop rational acceptance criteria have led to the emergence of probabilistic procedures in performance‐based seismic engineering. The Pacific Earthquake Engineering Research performance‐based methodology is one such approach. In this paper, the impact of certain modelling decisions made at different stages of the evaluation process on the performance assessment of a typical multi‐bent viaduct is examined. Modelling, in the context of this paper, covers hazard modelling, structural modelling and loss modelling. The specific application considered in this study is a section of an existing viaduct in California: the I‐880 interstate highway. Several simulation models of the viaduct are developed, a series of nonlinear time‐history analyses are carried out to predict demands, measures of damage are evaluated and the probability of closure of the viaduct is estimated using the specified hazard for the site. It is concluded that the methodology offers several advantages over existing deterministic performance‐based procedures. Results of the investigation indicate that the assessment methodology is particularly sensitive to the reliability of decisions made by bridge inspectors following a seismic event, and to the dispersion in the demand estimation, which in turn is influenced by several factors including soil–structure interaction effects and ground motion scaling procedures. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
57.
文章主要对使用大比例尺进行海底地形测量方法进行了简要的描述,测量过程中的方法技术、数据处理方法、测量效果说明多波束在复杂地形条件下可以取得良好的效果。 相似文献
58.
59.
60.
钢筋混凝土桥墩非线性地震反应分析 总被引:2,自引:0,他引:2
采用Takeda滞回曲线模型,对三个不同周期的桥墩,分别输入多条具有相同反应谱的地震波,计算了桥墩的线性和非线性时程响应,通过比较线性和非线性最大地震位移响应发现,在这些地震波作用下,虽然线性位移响应最大值基本相同,但非线性位移响应最大值差别很大。 相似文献