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101.
This article analyzes the structural composition of the chicana/o novel …y no se lo tragó la tierra, by Tomás Rivera, a book that has become a collective point of reference for chicana/o culture and community. Its structure will be explained, including the importance of personal and collective memory as elements that evolve every chapter as a fragmentary part of a whole. The classical concept of "art of memory" joined to the rhetoric of discourse opens a new perspective to analyze this fragmentation and helps the reader to understand the connection of its elements. Finally, the idea of "theater of memory" may be applied to the novel's chicana/o universe as a dramatic device for structuring the narrator's personal memories, achieving a final literary composition similar to a memorable, collective altarpiece full of impressive images from this community's daily struggle in the 1960s.  相似文献   
102.
The deformation of beam-column joints may contribute significantly to drift of reinforced concrete (RC) frames. In addition, failure may occur in the joints due to cumulative concrete crushing from applied beam and column moments, bond slip of embedded bars or shear failure as in the case of existing frames with nonductile detailing. When subjected to earthquake loading, failure in RC structural wall is similar to failure of frame joints as it may occur due to cumulative crushing from high flexural stresses, bond slip failure of lap splice, shear failure or a combination of various mechanisms of failure. It is important to include these behavioural characteristics in a simple model that can be used in the analysis of RC frames and RC walls to predict their response under earthquake loading and determine their failure modes.

Global macro models for the beam-column joint and for RC structural walls are developed. The proposed models represent shear and bond slip deformations as well as flexural deformations in the plastic hinge regions. The models are capable of idealising the potential failure mechanism due to crushing of concrete, bond slip or shear with allowance for the simultaneous progress in each mode. The model predictions are compared with available experimental data and good correlation is observed between analytical results and the test measurements.  相似文献   
103.
A new approach has been developed for finding optimal location of sensors in 3D multi-storeyed buildings. This approach is based on the compact probabilistic representation of acceleration response in terms of its covariance matrix. For a specified number of sensors, the optimal location has been taken to be the one for which the computed covariance matrix is closest to the exact covariance matrix of the random field constituted by the acceleration response process. It has been found that the determined sensor locations match favourably with those predicted by earlier studies for the special case of shear buildings. Further, the optimality of the determined sensor locations has also been verified by identifying the system parameters from the time series data and comparing them with those of the Finite Element Model.  相似文献   
104.
Due to lack of strong motion records, point-source and finite-fault models have been used to simulate far-field motions at Memphis and St. Louis Cities from earthquake events in the New Madrid Seismic Zone. However, near-field rock motions and their associated uncertainties have never been studied within this zone. The objectives of this study are to develop a simple procedure to account for the uncertainty effect of earthquake source parameters, to analyze the sensitivity of near-field rock motions to input source parameters, and finally, to generate rock motions at two sites located within 11 km from the southwestern segment (strike-fault) and a third site bove the Reelfoot Rift (reverse fault) using a well-validated finite-fault simulation program; FINSIM. An equal-weight logic tree was developed to ensure that the assumed uncertainties are within physical, geological, and seismological constraints. For each site, 100 acceleration time histories with various combinations of parameter uncertainties were respectively simulated for an earthquake of M w 7.0, 7.5, and 8.0 from each of the two faults. Their average spectral accelerations were in good agreement with those derived from the attenuation relation-ships representative to the Central and Eastern United States. Numerical simulations indicated that spectral accelerations are sensitive to the slip velocity, depth to top of fault, fault strike, slip distribution, and hypocentre location along the strike.  相似文献   
105.
In this paper, an effective active control algorithm is developed for the vibration control of non-linear structural systems subjected to earthquake excitation. It is an attempt to include the non-linear characteristics of the structural behaviour throughout the entire analysis (design and validation), accounting for the eventual cumulative structural damage and energy dissipation. This is a very important factor since, in current design practice, structures are assumed to behave nonlinearly when subjected to strong ground motion. The proposed algorithm focusses on the instantaneous optimal control approach for the development of the control algorithm where the nonlinearities are brought into the analysis through a non-linear state vector and a non-linear open loop term. A performance index that is quadratic in the control force and in the non-linear states and is subjected to a non-linear constraint equation, is minimised at every time step. The effectiveness of the proposed non-linear instantaneous optimal control (NIOC) strategy is critically evaluated in comparison with currently available active control techniques. Numerical simulation results indicate that the proposed approach provides a significant reduction of the peak response quantities, such as maximum response deformation, maximum response acceleration, ductility of the system, associated with a reduced maximum control force.  相似文献   
106.
Increasing carnivory is frequently cited as one of the key trajectories in the course of hominin evolution, yet the ethnographic record demonstrates that hunting is a high-variance, risky strategy necessitating a fundamental re-organisation of the foraging pattern. Hunter-gatherers rely on intra-band sharing of hunted resources as well as inter-band insurance mechanisms to mitigate against the risk of resource failure. It is suggested that logistical mobility functions to increase encounter rates with both prey and representatives of neighbouring groups, and is thus a fundamental part of the hunting adaptation. Implementation of an ideal gas model of encounter rate demonstrates that, when logistical mobility is regarded as a basic group fission pattern, it increases encounter rates for all groups relying on greater than 34% hunting. This equates to a shift in the optimal hunting percentage, as defined by encounter rates, from 24% under residential mobility to 35% under a logistical mobility strategy. These results are discussed in relation to fission–fusion social systems in primates and social carnivores, with a view to highlighting the specific aspects in which these differ from human foraging strategies.  相似文献   
107.
This article describes the development of a GIS-based model of historical drought and population change in western Canada, designed to support qualitative field research into drought adaptation and migration. The model combines digitized census data and recently available modeled historical climate data at a 10 km2 grid cell scale and can be used to generate maps of ‘hotspots’ where historical declines in rural populations may be associated with extended periods of heat and lack of precipitation. The results suggest a promising avenue for expanding and refining GIS-based modeling of historical human–climate interactions to support qualitative research and to potentially serve as a stepping stone toward forecasting future risk areas of drought-related migration in continental dryland areas.  相似文献   
108.
Hydro-political dependencies between countries are widely regarded as having important implications for international water cooperation and conflict. Quantitative ex-post empirical research on the subject so far uses very simple characterizations of international river geography to proxy for such dependencies, though. The authors developed a new geo-spatial dataset for water catchments worldwide. This dataset combines elevation models, flow accumulation approaches, hydrological data, and data on international boundaries to generate more precise and nuanced measures of hydro-political dependencies among riparian countries. The paper discusses these measurement concepts, illustrates how dependencies are distributed worldwide, and revisits three prominent quantitative studies on the issue to show how using improved data affects empirical findings. In contrast to a very popular presumption, upstream–downstream dependencies turn out to have a very small to insignificant effect on international water cooperation or conflict.  相似文献   
109.
In this paper we use non-ambiguous collections and sightings data from the 18th century to generate potential distribution models of three species of South American ungulates. These ungulates (Lama guanicoe -guanaco-; Ozotoceras bezoarticus -pampas deer- and Blastoceros dichotomus -marsh deer-) have different and specific environmental requirements. Through MaxEnt software, twenty-two environmental variables that characterize the distribution area of each species are defined. Once the models are generated, they are compared with the faunal associations found at Late Holocene archaelogical sites in order to infer paleoenvironmental conditions. We also discuss the role played by humans in the faunal associations which are "anomalous" or inconsistent with those models, like the spatial overlap of guanaco and marsh deer.  相似文献   
110.
This paper investigates the impact of the main criterion employed by the European Commission for the allocation of the largest portion of Structural Funds, based on the threshold of the 75% of European Union (EU) average gross domestic product (GDP) per capita. We focus on the 2014–2020 programming period and on EU-15 regions to analyze if this criterion has penalized some of them, as a consequence of the 2004 EU enlargement, which has represented an exogenous shock in the allocation process, due to the economic backwardness of new member states. Through the application of Synthetic Control Methods and Difference-in-Differences estimators at different geographical scales, we show that regions that did not obtain the less developed status in both the programming period 2007–2013 and 2014–2020, but that would have obtained it in the period 2014–2020 without the 2004 EU enlargement, experienced a significantly lower GDP per capita growth between −10.5% and −5.7%. Conversely, territories that in the period 2014–2020 lost the less developed status, previously obtained in the time frame 2007–2013, were not characterized by a significantly lower economic growth, providing some evidence of the effectiveness of the safety net.  相似文献   
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