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131.
A structure that has a permanent offset from a true vertical line is commonly referred to as being ‘out‐of‐plumb’. Out‐of‐plumb may result from construction tolerances or post‐earthquake permanent deformations in steel buildings. This paper quantifies the displacements of buildings with out‐of‐plumb in subsequent seismic events by means of inelastic dynamic time history analysis. Structures considered have different structural heights, force design reduction factors (R), and target inter‐story drifts. It is shown that buildings with greater out of plumb and force design reduction factor have larger normalized peak inter‐story drift ratio and ratio of residual‐to‐peak drift. Also, the ratio of residual‐to‐peak drift was not strongly dependent on structural height or design drift. A design procedure and example provided, based on the results obtained, show how peak and residual inter‐story drift ratio can be estimated. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
132.
在山东省枣庄市某棚户区改造项目前期的岩土工程勘察和物探勘查中,发现部分建筑物及车库基础下存在采空区及采煤巷道。根据前期工作,对其中一条巷道进行了注浆处理。处理后,利用高密度电阻率法对注浆位置进行了物探勘查,认为该处注浆后视电阻率升高,原低阻异常区明显减小或者消失,注浆采空区与未注浆采空区有明显的电性差异,未注浆区的明显低阻异常为分辨注浆区位置和效果提供了对比参考。但在使用电阻率法对注浆区进行检测时,要保证水泥浆固结,否则无法有效区分原充水采空区及未固结水泥浆引起的视电阻率异常,不利于判断注浆效果。因此,用物探方法检测注浆效果,可为工程顺利施工提供相应的参考依据。 相似文献
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地块—海槽边缘带成油成气新概念 总被引:1,自引:0,他引:1
对准噶尔,塔里木等盆地沉积环境的研究表明,古生代时,中国西北区海相沉积,沉积盆地的基底是一些离散的古老结晶地块,其上海水侵浸,地块之间为大洋或窄大洋的海槽,地块之间的海槽或地块与海槽过渡的边缘带盆地是油气形成的有利地带。 相似文献
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强震加速度记录中50点采样与200点采样之间的差别有多大,能否用50点记录代替200点记录,本文从49组200点记录中采取高通滤波的方法抽取成49组50点的记录,通过最大值对比、加速度时程对比、功率谱对比及滤波后两组数据的相关性共4个方面进行分析研究,发现滤波后的最大值比200点原始记录最大值平均小79.82 Count是原始记录的0.672%,加速度时程方面几乎没有什么差别,功率谱对比方面发现从0.4~90Hz之间谱曲线基本重合,而在该频段以外两端悬殊较大,最后,通过对6组200点与50点数据的相关分析后发现,其平均相关系数达到88%以上。 相似文献
138.
H.-W. Ma 《Stochastic Environmental Research and Risk Assessment (SERRA)》2002,16(6):464-478
There exist many sites with contaminated groundwater because of inappropriate handling or disposal of hazardous materials
or wastes. Health risk assessment is an important tool to evaluate the potential environmental and health impacts of these
contaminated sites. It is also becoming an important basis for determining whether risk reduction is needed and what actions
should be initiated. However, in research related to groundwater risk assessment and management, consideration of multimedia
risk assessment and the separation of the uncertainty due to lack of knowledge and the variability due to natural heterogeneity
are rare. This study presents a multimedia risk assessment framework with the integration of multimedia transfer and multi-pathway
exposure of groundwater contaminants, and investigates whether multimedia risk assessment and the separation of uncertainty
and variability can provide a better basis for risk management decisions. The results of the case study show that a decision
based on multimedia risk assessment may differ from one based on risk resulting from groundwater only. In particular, the
transfer from groundwater to air imposes a health threat to some degree. By using a methodology that combines Monte Carlo
simulation, a rank correlation coefficient, and an explicit decision criterion to identify information important to the decision,
the results obtained when uncertainty and variability are separate differ from the ones without such separation. In particular,
when higher percentiles of uncertainty and variability distributions are considered, the method separating uncertainty and
variability identifies TCE concentration as the single most important input parameter, while the method that does not distinguish
the two identifies four input parameters as the important information that would influence a decision on risk reduction. 相似文献
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从分析钢管的受力及地层可夯性出发,探讨气动夯管法的施工工艺问题,包括施工过程、气动夯管锤及空压机的选用、铺管精度、注浆润滑以及在其它工程中的应用等。 相似文献