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991.
《水文科学杂志》2013,58(1):66-82
Abstract An adaptive model for on-line stage forecasting is proposed for river reaches where significant lateral inflow contributions occur. The model is based on the Muskingum method and requires the estimation of four parameters if the downstream rating curve is unknown; otherwise only two parameters have to be determined. As the choice of the forecast lead time is linked to wave travel time along the reach, to increase the lead time, a schematization of two connected river reaches is also investigated. The variability of lateral inflow is accounted for through an on-line adaptive procedure. Calibration and validation of the model were carried out by applying it to different flood events observed in two equipped river reaches of the upper-middle Tiber basin in central Italy, characterized by a significant contributing drainage area. Even if the rating curve is unknown at the downstream section, the forecast stage hydrographs were found in good agreement with those observed. Errors in peak stage and time to peak along with the persistence coefficient values show that the model has potential as a practical tool for on-line flood risk management. 相似文献
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AbstractThe rating curve model (RCM) proposed by Moramarco and co-authors is modified here for flood forecasting purposes without using rainfall information. The RCM is a simple approach for discharge assessment at a river site of interest based on relating the local recorded stage and the remote discharge monitored at an upstream gauged river site located some distance away. The proposed RCM for real-time application (RCM-RT), involves only two parameters and can be used for river reaches where significant lateral flows occur. The forecast lead time depends on the mean wave travel time of the reach. The model is found to be accurate for a long reach of the Po River (northern Italy) and for two branches of the Tiber River (central Italy) characterized by different intermediate drainage areas and wave travel times. Moreover, the assessment of the forecast uncertainty coming from the model parameters is investigated by performing a Monte Carlo simulation. Finally, the model capability to accurately forecast the exceedence of fixed hydrometric thresholds is analysed.Editor D. Koutsoyiannis; Associate editor C. Perrin 相似文献
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Seven temperature‐based equations, each representing a typical form, were evaluated and compared for determining evaporation at two climatological stations (Rawson Lake and Atikokan) in north‐western Ontario, Canada. The comparison was first made using the original constant values involved in each equation, and then using the recalibrated constant values. The results show that when the original constant values were used, larger biases existed for most of the equations for both stations. When recalibrated constant values were substituted for the original constant values, six of the seven equations improved for both stations. Using locally calibrated parameter values, all seven equations worked well for determining mean seasonal evaporation values. For monthly evaporation values, the modified Blaney–Criddle method produced least error for all months for both stations, followed by the Hargreaves and Thornthwaite methods. The Linacre, Kharrufa and Hamon methods showed a significant bias in September for both stations. With properly determined constant values, the modified Blaney–Criddle, the Hargreaves and Thornthwaite methods can be recommended for estimating evaporation in the study region, as far as temperature‐based methods are concerned. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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This paper presents a detailed analysis of a real‐time pseudodynamic test system using a system transfer function. The analysis considers the actuator control scheme, the dynamics of the actuator, test structure, and actuator reaction frame, the influence of actuator time delay on response computation, and methods to compensate for the time‐lag errors. It has been observed that the system can achieve an excellent performance with optimum control gains. The two error‐compensation methods presented here are also proven to be effective. Further, it has been demonstrated that the adverse effect of the inertia force developed by the test structure can be corrected for during a real‐time test, and that the influence of the reaction frame flexibility is small when the frame is reasonably massive and stiff as compared to the test structure. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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研究了面向小样本分类的高光谱影像特征提取技术,提出了一种用于小样本分类的投影寻踪指标和基于SVMPP的高光谱影像特征提取方法;并借助误差校正输出码,将两类问题的特征提取推广到多类情况。通过高光谱影像分类实验证明,该方法具有很强的小样本学习能力,能够在先验信息很少的情况下较准确地提取地物的分类特征。 相似文献
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