全文获取类型
收费全文 | 299篇 |
免费 | 110篇 |
国内免费 | 48篇 |
专业分类
测绘学 | 1篇 |
地球物理 | 277篇 |
地质学 | 161篇 |
海洋学 | 3篇 |
综合类 | 9篇 |
自然地理 | 6篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 15篇 |
2019年 | 27篇 |
2018年 | 30篇 |
2017年 | 14篇 |
2016年 | 24篇 |
2015年 | 14篇 |
2014年 | 20篇 |
2013年 | 34篇 |
2012年 | 30篇 |
2011年 | 27篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 21篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 18篇 |
2004年 | 13篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
排序方式: 共有457条查询结果,搜索用时 78 毫秒
151.
152.
153.
混凝土小砌块约束砌体结构,由于加入芯柱、构造柱、圈梁,使结构整体性提高,因此具有较好的抗震性能和发展前景。通过整理94个混凝土小砌块约束砌体墙片试验数据,考虑权重,统计了混凝土小砌块约束砌体墙片延性系数,给出了延性系数与高度、延性系数比与高宽的关系,同时给出了层间开裂位移角、层间极限位移角公式,以及接近倒塌时混凝土小砌块约束砌体结构层间位移的计算公式,并与一个八层混凝土小砌块约束砌体结构的动力时程分析结果进行了对比,结果显示,最大误差在顶层,为17.7%,因此,所提层间位移计算公式是可以满足工程精度需要的,为混凝土小砌块约束砌体结构基于性态的抗震分析提供参考。 相似文献
154.
地下水易污染性分析是合理开发利用地下水资源、保护地下水环境的一项重要的基础性工作.长期以来针对潜水含水层易污染性的研究进行的较为深入,而对承压含水层易污染性的研究较为少见.同时,易污染性评价方法又以经验方法为主,受人为主观因素影响较大,因此需要通过对承压含水层污染机理进行研究,以减少人为主观因素对评价结果的影响.本文以单井开采承压含水层为例,通过分析承压含水层受污染的原因,以单位面积上越流补给量占开采量的比重为承压含水层易污染性指数,在建立越流区承压水向完整井稳定运动的微分方程的基础上,得到易污染性指数的解析表达式,并分析了各参数对易污染性的影响,使承压含水层易污染性评价有了一定的理论依据,对合理开发利用承压含水层有一定的指导意义. 相似文献
155.
Building pounding damages observed in the February 2011 Christchurch earthquake are described in this paper. The extent and severity of pounding damage is presented based on a street survey of Christchurch's central business district. Six damage severity levels and two confidence levels are defined to classify the observed damage. Generally, pounding was observed to be a secondary effect. However, over 6% of the total surveyed buildings were observed to have significant or greater pounding damage. Examples of typical and exceptional pounding damage are identified and discussed. Extensive pounding damage was observed in low‐rise unreinforced masonry buildings that were constructed with no building separation. Modern buildings were also endangered by pounding when building separations were infilled with solid architectural flashings. The damage caused by these flashings was readily preventable. The observed pounding damage is compared to that observed in the September 2010 Darfield earthquake to explore if the damage could have been predicted. It is found that pounding prone buildings can be identified with reasonable accuracy by comparing configurations to characteristics previously noted by researchers. However, detailed pounding damage patterns cannot currently be precisely predicted by these methods. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
156.
A shaking table testing program was undertaken with the main objective of providing basic information for the calibration of analytical models, and procedures for determining seismic response of typical stone masonry temples of the 16–18th centuries stone masonry construction in Mexico. A typical colonial temple was chosen as a prototype. A model at a 1:8 geometric scale was built with the same materials and techniques as the prototype, and was subjected to horizontal and vertical motions of increasing intensities. The maximum applied intensity corresponded to a base shear force of about 58 of the total building weight. Vertical component of the base motion significantly affected the response and increased the damage of the model. Damage patterns were similar to those observed in actual temples. Damping coefficients of the response ranged from 7 for undamaged state, reached about 14 for severe damage. The main features of the measured response were compared with those computed using a nonlinear, finite element model; for the latter, a constitutive law developed for plain concrete was adopted for reproducing cracking and crushing of the irregular stone masonry. Observed damage patterns as well as measured response could be reproduced with reasonable accuracy by the analytical simulation, except for some local vibrations, as those at the top of the bell towers. It can be concluded that the simple constitutive law adopted for the simulation was able to reproduce the experimental response with reasonable level of accuracy. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
157.
?????й????363????????λ???????????????????????????NAKAI???????3???????????????????????????????9?????????????????????????????????????????????????????????A??B??C??D??E????????????????????????? 相似文献
158.
A field reconnaissance mission was led to the areas affected by the disaster caused by the Magnitude 7.9 earthquake event
of 15/08/2007 near the city of Pisco in Peru. The main objectives of the mission were to collect data and make observations
leading to improvements in design methods and techniques for strengthening and retrofit, and to assist the phase of reconstruction.
The mission focused on the behaviour of non-engineered structures, in particular those of adobe constructions. The findings
of the mission confirmed that most of the damage was observed on adobe houses constructed with traditional non anti-seismic
techniques which either collapsed or nearly collapsed, causing 519 deaths, 1,366 injuries and more than 58,000 houses destroyed.
The mission also confirmed that buildings constructed according to modern earthquake resistant design standards performed
with no evident damage. All the parties contacted during the mission, especially the EC Delegation, showed particular interest
in the results of the present mission report, which will be taken into consideration when planning the reconstruction phase,
especially of the most distant rural areas, where close collaboration between the Governmental Institutions, International
Organizations, Universities and NGO’s, will be needed to assist the population for the adoption of earthquake resistant designs
in the reconstruction of the destroyed houses. 相似文献
159.
160.