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81.
Seismic performance of an unreinforced masonry building: An experimental investigation 总被引:1,自引:0,他引:1
This paper presents the results of an experimental investigation carried out to investigate the seismic performance of a two storey brick masonry house with one room in each floor. A half‐scale building constructed using single wythe clay brick masonry laid in cement sand mortar and a conventional timber floor and timber roof clad with clay tiles was tested under earthquake ground motions on a shaking table, first in the longitudinal direction and then in the transverse direction. In each direction, the building was subjected to different ground motions with gradually increasing intensity. Dynamic properties of the system were assessed through white‐noise tests after each ground motion. The building suffered increasing levels of damage as the excitations became more severe. The damage ranged from cracking to global/local rocking of different piers and partial out‐of‐plane failure of the walls. Nevertheless, the building did not collapse under base excitations with peak ground acceleration up to 0.8g. General behaviour of the tested building model during the tests is discussed, and fragility curves are developed for unreinforced masonry buildings based on the experimental results. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
82.
The parameter estimation methods of (1) moments, (2) maximum‐likelihood, (3) probability‐weighted moments (PWM) and (4) self‐determined PWM are applied to the probability distributions of Gumbel, general extreme values, three‐parameter log‐normal (LN3), Pearson‐3 and log‐Pearson‐3. The special method of computing parameters so as to make the sample skewness coefficient zero is also applied to LN3, and hence, altogether 21 candidate distributions resulted. The parameters of these distributions are computed first by original sample series of 14 successive‐duration annual extreme rainfalls recorded at a rain‐gauging station. Next, the parameters are scaled by first‐degree semi‐log or log‐log polynomial regressions versus rainfall durations from 5 to 1440 min (24 h). Those distributions satisfying the divergence criterion for frequency curves are selected as potential distributions, whose better‐fit ones are determined by a conjunctive evaluation of three goodness‐of‐fit tests. Frequency tables, frequency curves and intensity–duration–frequency curves are the outcome. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
83.
Faulting is one type of permanent ground displacement (PGD); tunnels are at the risk of damage when they are susceptible to faulting. The present study proposes an experimental approach to create the fragility curves for shallow segmental tunnels in alluvial deposits subjected to normal surface faulting. Centrifuge testing was carried out in order to achieve this purpose. The proposed approach allows evaluation of new fragility curves considering the distinctive features of tunnel geometry and fault specifications. The comparison between the new fragility curves and the existing empirical curves was discussed as well. Compared to tunnels in rock, tunnels in alluvial deposits are more susceptible to failure because of different mechanisms of collapse into tunnel at large exerted PGD. 相似文献
84.
《The Professional geographer》2013,65(3):321-326
A regret frequently expressed at International Geographical Congresses concerns the lack of summary information about the nature of geographic research in the host country. During a discussion of this point with members of the Association of Japanese Geographers, the idea of publishing a series of reports on various aspects of Japanese research surfaced. The concept was later enthusiastically supported by the United States National Committee for the International Geographical Union. This first report, “Historical Geography in Japan,” has been modified for the benefit of the English-speaking readers of THE PROFESSIONAL GEOGRAPHER. Although the reports will be of particular interest to those planning to attend the 1980 IGC in Tokyo, they should prove of general interest as well.—H. Jesse Walker, Member, U.S. National Committee, IGU. 相似文献
85.
86.
Using experimental data to reduce the single-building sigma of fragility curves: case study of the BRD tower in Bucharest, Romania 总被引:1,自引:0,他引:1
Matthieu Perrault Philippe Gueguen Alexandru Aldea Sorin Demetriu 《地震工程与工程振动(英文版)》2013,12(4):643-658
The lack of knowledge concerning modelling existing buildings leads to significant variability in fragility curves for single or grouped existing buildings. This study aims to investigate the uncertainties of fragility curves, with special consideration of the single-building sigma. Experimental data and simplified models are applied to the BRD tower in Bucharest, Romania, a RC building with permanent instrumentation. A three-step methodology is applied: (1) adjustment of a linear MDOF model for experimental modal analysis using a Timoshenko beam model and based on Anderson's criteria, (2) computation of the structure's response to a large set of accelerograms simulated by SIMQKE software, considering twelve ground motion parameters as intensity measurements (IM), and (3) construction of the fragility curves by comparing numerical interstory drift with the threshold criteria provided by the Hazus methodology for the slight damage state. By introducing experimental data into the model, uncertainty is reduced to 0.02 considering Sd ) as seismic intensity IM and uncertainty related to the model is assessed at 0.03. These values must be compared with the total uncertainty value of around 0.7 provided by the Hazus methodology. 相似文献
87.
Issa E. Issa 《水文科学杂志》2013,58(7):1456-1466
AbstractMosul Dam is one of the biggest hydraulic structures in Iraq. Its storage capacity is 11.11 × 109 m3 at a maximum operation level of 330 m a.s.l. The dam became operational in 1986 and no survey has been conducted to determine its storage capacity and establish new operational curves since this date. A topographic map of scale 1:50 000 dated 1983 was converted into triangulated irregular network (TIN) format using the ArcGIS program to evaluate the operational curves. Then the reservoir was surveyed in 2011 to establish the reduction in its storage capacity and to develop new operational curves. The results indicated that the reduction in the storage capacity of the reservoir was 14.73%. This implies that the rate of sedimentation within the reservoir was 45.72 × 106 m3 year?1. These results indicate that most of the sediment was deposited within the upper zone of the reservoir where the River Tigris enters the reservoir.Editor D. KoutsoyiannisCitation Issa, E.I., Al-Ansari, N., and Knutsson, S., 2013. Sedimentation and new operational curves for Mosul Dam, Iraq. Hydrological Sciences Journal, 58 (7), 1456–1466. 相似文献
88.
ABSTRACTRecession curves are widely used in hydrological studies and projects, such as in rivers, streams or springs. However, no cave drip water has been analysed with recession curves. In this paper, four cave drips were monitored in the Velika Pasica Cave, in order to discover the water flow and storage properties of the epikarst. Various methods were applied in the recession analysis, combining the hydrological characteristics of the four drips: for the slow water in the epikarst, the matching strip method was the identified as the appropriate model for the drip water recession analysis. According to the recession coefficient k, the water flow in the epikarst was divided into fast flow, intermediate flow and slow flow. The volume of water retained in the reservoir (the epikarst storage) could be presented as a function of its specific recession coefficient.
EDITOR D.Koutsoyiannis; ASSOCIATE EDITOR X. Chen 相似文献
89.
90.
ABSTRACTRecords of precipitation extremes are essential for hydrological design. In urban hydrology, intensity–duration–frequency curves are typically estimated from observation records. However, conventional approaches seldom consider the areal extent of events. If they do, duration-dependent area reduction factors are used, but precipitation is measured at only a few locations. Due to the high spatial variability of precipitation, it is relatively unlikely that a gauged observation network will capture the extremes that occur during a precipitation event. Therefore, the area reduction approach cannot be regarded as the reduction of an observed maximum. To investigate precipitation extremes, spatial aspects need to be considered using different approaches. Here, we both address the conventional practice of area reduction and consider a within-area chance of increased precipitation, defined as the maximum precipitation intensity observed in a cluster within a selected domain. The results show that (1) the risk of urban flooding is routinely underestimated in current design practice, and (2) traditional calculations underestimate extremes by as much as 30–50%. We show how they can be revised sensibly. 相似文献