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81.
三峡库区巫山新县城库岸再造模式及塌岸预测   总被引:1,自引:0,他引:1  
简要介绍了三峡库区巫山新县城地质环境,分析了库岸再造模式,对最终库坡塌岸宽度进行了预测。  相似文献   
82.
基于GM(1,1)模型的矿井瓦斯涌出量预测研究   总被引:5,自引:0,他引:5  
应用灰色系统理论,建立了预测矿井瓦斯涌出量的灰色系统GM(1,1)模型,并用残差序列对预测模型进行了修正。实例表明,该模型的计算精度符合工程实际,可用于矿井瓦斯涌出量的预测。  相似文献   
83.
以综放面支承压力分布规律研究成果为基础,建立了济三煤矿3下煤层开采沉陷预测模型。利用不同深度、不同工作面长度的两个工作面的开采沉陷实测结果耦合,解决了济三煤矿3下煤层开采沉陷预测模型中有关“常数”的确定问题。现场实测证明,所建立的开采沉陷预测模型的预测精度能满足客观实际的要求。  相似文献   
84.
The importance of applying unsaturated soil mechanics to geotechnical engineering design has been well understood. However, the consumption of time and the necessity for a specific laboratory testing apparatus when measuring unsaturated soil properties have limited the application of unsaturated soil mechanics theories in practice. Although methods for predicting unsaturated soil properties have been developed, the verification of these methods for a wide range of soil types is required in order to increase the confidence of practicing engineers in using these methods. In this study, a new permeameter was developed to measure the hydraulic conductivity of unsaturated soils using the steady-state method and directly measured suction (negative pore-water pressure) values. The apparatus is instrumented with two tensiometers for the direct measurement of suction during the tests. The apparatus can be used to obtain the hydraulic conductivity function of sandy soil over a low suction range (0–10 kPa). Firstly, the repeatability of the unsaturated hydraulic conductivity measurement, using the new permeameter, was verified by conducting tests on two identical sandy soil specimens and obtaining similar results. The hydraulic conductivity functions of the two sandy soils were then measured during the drying and wetting processes of the soils. A significant hysteresis was observed when the hydraulic conductivity was plotted against the suction. However, the hysteresis effects were not apparent when the conductivity was plotted against the volumetric water content. Furthermore, the measured unsaturated hydraulic conductivity functions were compared with predictions using three different predictive methods that are widely incorporated into numerical software. The results suggest that these predictive methods are capable of capturing the measured behavior with reasonable agreement.  相似文献   
85.
An artificial neural network based system (NN earth) is developed for construction practitioners as a simple tool for predicting earthmoving operations, which are modelled by back propagation neural networks with four expected parameters and seven affecting factors. These networks are then trained using the data patterns obtained from simulation because there are insufficient data available from industrial sources. The trained network is then incorporated as the computation engine of NN earth. To engender confidence in the results of neural computation, a validation function is implemented in NN earth to allow the user to apply the engine to historic cases prior to applying it to a new project. An equipment database is also implemented in NN earth to provide default information, such as internal cost rate, fuel cost, and operator's cost. User interfaces are developed to facilitate inputting project information and manipulating the system. The major functions and use of NN earth are illustrated in a sample application. In practice, NN earth can assist the user either in selecting a crew to minimize the unit cost of a project or in predicting the performance of a given crew.  相似文献   
86.
Based on experimental results concerning the compressive strength development of concrete containing fly ash, the authors derived an estimation equation for compressive strength development. The equation can express coefficient , which indicates the activity of fly ash as a binder, in the form of a function of age, fly-ash content, and Blaine specific surface area of fly ash.

This equation is capable of explaining the increases in the early strength due to fly ash in place of part of fine aggregate, the decreases in the early strength due to fly ash in place of part of cement, the increases in the long-term strength due to pozzolanic reaction, the relationship between the fly-ash replacement ratio and the ratio of strength increase/decrease, and the effect of fly ash's Blaine specific surface area on the strength.  相似文献   

87.
Abstract. We consider the problem of predicting and interpolating linearly a time series which can be represented as the sum of a model process with known spectral density and a noise process. The spectral density of the noise process is unknown with the exception of an upper bound for its integral. Some partial information of quite general kind about the cross spectral density of model and noise is available. We prove the existence of a robust predictor which minimizes the maximal mean-square error, where the maximum is taken over all spectral densities which may arise from the circumstances described above as spectral density of the predicted time series. An analogous result holds for the related interpolation problem. We describe how to derive the minimax robust predictor and interpolator in concrete situations. The method is illustrated by determining the robust predictor explicitly for three examples where model and noise may be arbitrarily, only causally or not at all correlated.  相似文献   
88.
运用线性回归对预测数据进行分析,剔除异常数据,用GM(1,1)模型进行预测,有效降低了数据相对误差,提高了预测数据的精度。选用印刷包衬压缩变形的压缩变形量值,用线性回归进行数据分析并剔除异常数据后用GM(1,1)进行预测,使得预测数据具有更高的准确性和适应性。实验及仿真结果表明,经过前期数据分析整理后的灰色预测模型,其预测期望值远优于单纯的回归模型和GM(1,1)模型。  相似文献   
89.
A new model to predict the adsorption equilibrium of mixtures containing supercritical components was presented. The difference in the adsorption mechanism between the supercritical components and the condensable components was accounted for in the new model. Lateral interaction in the adsorbed phase was also considered in the local isotherm. The new model was verified by the experimental data of the mixture CH4/CO2/C2H6 on activated carbon JX101 collected for 283-313 K and pressures up to . It was also verified with the experimental data published previously in literature. Considerable improvement in the prediction precision was achieved in using the new model to predict the adsorption of mixtures on activated carbon.  相似文献   
90.
移动对象的运动基本是在障碍空间里进行的。近几年,已有较多针对障碍空间中范围查询、近邻查询、聚类查询等的研究,但是目前尚没有对障碍空间中移动对象的位置预测进行研究。为此,研究了障碍空间中移动对象的位置预测;采用灰模型与线性模型相结合的办法,提出了一种基于R树的高效的剪枝算法;根据移动对象的运动规律性,提出了几条剪枝策略,从而大大减少了需要处理的障碍对象个数。最后,通过实验验证了算法的准确性和高效性。  相似文献   
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