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171.
The local design and construction practices in the United Arab Emirates(UAE),together with Dubai’s unique rate of development,warrant special attention to the selection of Lateral Force-Resisting Systems(LFRS).This research proposes four different feasible solutions for the selection of the LFRS for tall buildings and quantifies the impact of these selections on seismic performance and cost.The systems considered are: Steel Special Moment-Resisting Frame(SMRF),Concrete SMRF,Steel Dual System(SMRF with Special Steel Plates Shear Wall,SPSW),and Concrete Dual System(SMRF with Special Concrete Shear Wall,SCSW).The LFRS selection is driven by seismic setup as well as the adopted design and construction practices in Dubai.It is found that the concrete design alternatives are consistently less expensive than their steel counterparts.The steel dual system is expected to have the least damage based on its relatively lesser interstory drifts.However,this preferred performance comes at a higher initial construction cost.Conversely,the steel SMRF system is expected to have the most damage and associated repair cost due to its excessive flexibility.The two concrete alternatives are expected to have relatively moderate damage and repair costs in addition to their lesser initial construction cost. 相似文献
172.
This paper studies the temporal and spatial distribution of great global earthquakes( M W≥8.0) since 1900.We compare the two periods of upsurges of great earthquakes occurring in the middle of last century and beginning of this century.The former period took place between 1950 and 1965 during which 13 great earthquakes( M W≥ 8.0) occurred,including three events with moment magnitude greater than 9.0.The largest magnitude in this period reached 9.6.The latter period starts from the beginning of this century.In less than 12 years,15 great earthquakes have attacked the world with the largest magnitude being M W9.1.On the basis of comparison between these two upsurges of global earthquake activity,we infer that the ongoing high level of earthquake activity may continue for another five years or so.Numerous great earthquakes( M W≥8.0) and many large earthquakes( M W6.0~7.0) will occur globally in these five years.In addition,this paper also discusses the relationships between earthquake activity along the Sumatra segment of the Indian-Australia plate boundary and that in the Bayankala block in the middle of Qinghai-Tibetan plateau as well as in the blocks of the southern plateau.The results indicate that the Qinghai-Tibetan plateau,in particular its middle and southern parts,is a likely place for future earthquakes of magnitude over 7.0. 相似文献
173.
Spatial sensitivity of seismic hazard results to different models with respect to background seismic activity and earthquake occurrence in time is investigated. For the contribution of background seismic activity to seismic hazard, background area source with uniform seismicity and spatially smoothed seismicity models are taken into consideration. For the contribution of faults, through characteristic earthquakes, both the memoryless Poisson and the time dependent renewal models are utilized. A case study, involving the assessment of seismic hazard for the Bursa province in Turkey, is conducted in order to examine quantitatively the influence of these models on seismic hazard results. The spatial variation of the difference in Peak Ground Acceleration (PGA) values obtained from these different models is presented in the form of difference maps for return periods of 475 and 2475 years. Best estimate seismic hazard maps for PGA and Spectral Accelerations (SA) at 0.2 and 1.0 s are obtained by using the logic tree method. 相似文献
174.
基于区域构造背景、应力场状态及动力学环境等,将青藏高原北部地区划分为4个相对独立的统计单元,即祁连山地震带、甘东南地区、柴达木一共和地块及库玛地震带.通过地震频度和b值拟合确定了各个地区不同下限震级的地震目录完整性起始时间;确定了各构造单元中强以上地震活跃与平静交替活动的特征;定量计算了在平均状态中强以上地震活动特征参数及平静阶段与活跃阶段地震活动特征参数;分别获得了各个区域在平均、活跃与平静状态下的小震活动状态参数. 相似文献
175.
Véronique Léonardi François Arthaud Achkhen Tovmassian Arkadi Karakhanian 《Geodinamica Acta》2013,26(2-3):85-103
AbstractThis study presents the relationship between local seismicity and springs discharge, in which the microseismicity modifies the state of stress of the aquifer matrix and these modifications of the local stress control the aquifer behaviour from an example of a basaltic reservoir crossed by a seismic fault.Along the right-lateral Garni seismic wrench fault, the distribution in space and time of more than 500 micro-earthquakes has been studied providing a pattern of stress distribution. Together with this tectonic survey, the hydrographs of springs issuing from an aquifer located in basaltic lava flows and crossed by the fault have been gauged for 4 years. According to its tectonic, geologic and hydrodynamic properties, the reservoir has been divided in to several parts. The hydrological behaviour of the reservoir and of each of its parts has been modelled, based on the rainfall and hydrodynamic properties of the basaltic reservoir and of nearby reservoirs.The model allows us to define the ‘normal behaviour’ of the springs, when their discharge is not affected by an earthquake. Anomalies to the normal hydrometric curves are defined, and correlated to small (M < 3.5) earthquakes along the Garni fault. We propose that the circulation of underground water in the area around the fault depends largely on the fracture pattern of the basalts and the aquifer basement, as pointed out from field observations. Changes in spring discharges are explained by variations in the state of stress around the Garni fault, induced by the alternation of elastic strain and stick-slip movement on the fault, and by creep far from the fault. A model of stress distribution is proposed which explains changes in fracture charateristics before and after earthquakes. © Elsevier, Paris 相似文献
176.
177.
Earthquake swarms are often assumed to be caused by magmatic or fluid intrusions, where the stress changes in the vicinity
of the intrusion control the position, strength and rate of seismicity. Fracture mechanical models of natural intrusions or
man-made hydrofractures pose constraints on orientation, magnitude, shape and growing rate of fractures and can be used to
estimate stress changes in the vicinity of the intrusions. Although the idea of intrusion-induced seismicity is widely accepted,
specific comparisons of seismicity patterns with fracture models of stress changes are rarely done.
The goal of the study is to review patterns of intrusion-induced earthquake swarms in comparison to the observations of the
swarm in NW Bohemia in 2000. We analyse and discuss the theoretical 3D shape of intrusions under mixed mode loading and apparent
buoyancy. The aspect ratio and form of the intrusion is used to constrain parameters of the fluid, the surrounding rock and
stress. We conclude that the 2000 NW Bohemia swarm could have been driven by a magmatic intrusion. The intrusion was, however,
inclined to the maximal principal stress and caused shear displacement additional to opening. We estimate that the density
diference between magma and rock was small. The feeding reservoir was possibly much larger than the area affected from earthquakes
and may be a vertical dike beneath the swarm region. 相似文献
178.
179.
Comparison of source parameters estimated in the frequency and time domains for seismic events at the Rudna copper mine,Poland 总被引:3,自引:0,他引:3
Source parameters estimated in the frequency domain for 100 selected seismic events from the Rudna copper mine, with moment
magnitude ranging from 1.4 to 3.6, were collected to study their scaling relations and to compare them with the parameters
estimated in the time domain. The apparent stress and static stress drop, corrected for the limited bandwidth recording, increase
slightly in a similar manner with increasing seismic moment. The ratio of apparent stress to static stress drop, a measure
of radiation efficiency, is practically constant and its mean value is close to 0.1.
For 37 seismic events, with moment magnitude between 1.9 and 3.4, source parameters were estimated in the time domain from
relative source time functions, that displayed unilateral rupture propagation, and their rupture velocity could be estimated.
It ranges from 0.23 to 0.80 of shear wave velocity and is almost independent of seismic moment. The fault length, estimated
from the average source pulse width and rupture velocity, is clearly dependent on seismic moment and is smaller than the source
radius estimated from the corner frequency on the average by about 25 percent. There is no correlation between the values
of static stress drop estimated in the frequency and time domains, but the time domain stress drop is in general similar to
that estimated in the frequency domain. The apparent stress increases with increasing rupture velocity, and the ratio of apparent
stress to static stress drop seems also to depend on rupture velocity. 相似文献
180.