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71.
72.
Jamie E. Padgett 《地震工程与结构动力学》2011,40(15):1743-1761
Deteriorating highway bridges in the United States and worldwide have demonstrated susceptibility to damage in earthquake events, with considerable economic consequences due to repair or replacement. Current seismic loss assessment approaches for these critical elements of the transportation network neglect the effects of aging and degradation on the loss estimate. However, the continued aging and deterioration of bridge infrastructure could not only increase susceptibility to seismic damage, but also have a significant impact on these economic losses. Furthermore, the contribution of individual aging components to system‐level losses, correlations between these components, and uncertainty modeling in the risk assessment and repair modeling are all crucial considerations to enhance the accuracy and confidence in bridge loss estimates. In this paper, a new methodology for seismic loss assessment of aging bridges is introduced based on the non‐homogeneous Poisson process. Statistical moments of seismic losses can be efficiently estimated, such as the expected value and variance. The approach is unique in its account for time‐varying seismic vulnerability, uncertainty in component repair, and the contribution of multiple correlated aging components. A representative case study is presented with two fundamentally distinct highway bridges to demonstrate the effects of corrosion deterioration of different bridge components on the seismic losses. Using the proposed model, a sensitivity study is also conducted to assess the effect of parameter variations on the expected seismic losses. The results reveal that the seismic losses estimated by explicitly considering the effects of deterioration of bridge components is significantly higher than that found by assuming time‐invariant structural reliability. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
73.
Multiple-expert hazard/risk assessments have considerable precedent, particularly in the Yucca Mountain site characterization
studies. A certain amount of expert knowledge is needed to interpret the geological data used in a probabilistic data analysis.
As may be the situation in science, experts disagree on crucial points. Consequently, lack of consensus in some studies is
a sure outcome. In this paper, we present a Bayesian approach to statistical modeling in volcanic hazard assessment for the
Yucca Mountain site. Specifically, we show that the expert opinion on the site disruption parameterp is incorporated into the prior distribution, π(p), based on geological information that is available. Moreover, π(p) can
combine all available geological information motivated by conflicting but realistic arguments (e.g., simulation, cluster analysis,
structural control, ..., etc.). The incorporated uncertainties about the probability of repository disruptionp
eventually will be averaged out by taking the expectation over π(p). We use the following priors in the analysis: (1) priors
selected for mathematical convenience: Beta (r,s) for (r,s) = (2, 2), (3, 3), (5, 5), (2, 1),(2, 8), (8, 2), and (1, 1);and (2) three priors motivated by expert knowledge. Sensitivity analysis is performed for each prior distribution. Our study
concludes that estimated values of hazard based on the priors selected for mathematical simplicity are uniformly higher than
those obtained based on the priors motivated by expert knowledge. And, the model using the prior, Beta (8, 2), yields the
highest hazard (=2.97 × 10-2
. The minimum hazard is produced by the “three-expert prior” (i.e., values of
p
are equally likely for
p = 10-3, 10-2,and 10-1
. The estimate of the hazard is 1.39 × 10-3, which is only about one order of magnitude smaller than the maximum value. The term, “hazard, ” is defined as the probability
of at least one disruption of a repository at the Yucca Mountain site by basaltic volcanism for the next 10,000 years. 相似文献
74.
Abstract One of the basic tasks in geomorphologic analysis is to know the probability distributions of the stream lengths of different orders. In practical applications, this information is useful for basin rainfall-runoff modelling. The objective of this study is to determine the length distributions of the Strahler streams. A Poisson process was used to derive the theoretical distributions. The result showed that the length distribution of the first-order stream is an exponential distribution and the second-order or higher order stream length is a gamma distribution. In order to verify the theoretical distributions, a digital elevation model (DEM) was adopted to calculate the stream lengths of four basins in Taiwan. Kolmogorov-Smirnov and chi-square tests were used to test the goodness-of-fit of the data. Results showed that the length distributions of the first- and second-order streams analysed by using DEM correspond with those from the derived distribution method. 相似文献
75.
为了扩大洪水信息,提高洪水模拟精度,研究超定量洪水频率分析模型。介绍了洪水超定量模型的基本理论,假设超定量洪水年发生次数服从Poisson分布,超定量洪水系列服从广义Pareto(GP)分布,给出年最大超定量洪水分布和超定量洪水重现期的计算方法,提出通过模型拟合优度检验来综合确定超定量系列阈值的方法。将超定量模型应用在海河流域小觉站洪峰频率分析中,结果表明:通过模型拟合优度检验确定超定量系列阈值的方法有效且可靠,洪水超定量系列年平均发生次数服从Poisson分布,GP分布洪峰设计值略大于P-Ⅲ分布洪峰设计值,应用在水利工程设计及风险分析中是偏安全的。 相似文献
76.
77.
福建地区平均波速比的测定及初步分析 总被引:2,自引:0,他引:2
选取福建地震台网“十五”观测系统正式运行以来记录的2009-2012年的ML≥2.0级地震事件,根据断裂构造特征和地震的空间分布情况,将研究区域划分为3个地区。采用多台和达法计算波速比研究了福建地区的波速比和泊松比分布情况,并且讨论了2012年4月15日福建仙游ML4.1级地震前后的波速比变化特征。 相似文献
78.
79.
将外界因素对岩石变形的影响考虑为瞬间弹性损伤和长期蠕变损伤,并根据加载瞬间弹性模量及蠕变模量的劣化分别对瞬间弹性损伤变量和蠕变损伤变量进行定义,由此建立了考虑损伤的kBurgers模型。在此基础上,通过假定泊松比和体积模量为常量分别得到了对应的模型三维表达式,并得到了不同建模思路下模型参数间的换算关系。最后结合实际算例,对常体积模量假定下模型参数随含水率变化的损伤演化规律进行了分析,获得了常体积模量假定下模型的瞬间弹性损伤和长期蠕变损伤演化方程,检验了模型参数换算关系的有效性。 相似文献
80.
引入高阶重力场模型作为参考场,削弱局部重力场逼近中线性化误差的影响。以实测的陆地重力异常、船载重力异常及航空重力扰动为基础数据,基于泊松小波径向基函数分析不同参考场对局部重力场逼近的影响。结果表明,引入高阶全球重力场模型代替GRS80参考椭球正常场作为参考场,能更为准确地逼近真实的重力场,有效削弱线性化误差的影响。相比于基于GRS80正常场构建的似大地水准面模型,基于DGM1S重力场模型为参考场构建的似大地水准面的精度,在地形起伏较大的德国、英国及挪威区域分别提高了1.5 mm、3.3 mm和9.0 mm。 相似文献