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191.
《Robotics and Autonomous Systems》2014,62(3):330-339
We present a system that is able to autonomously build a 3D model of a robot’s hand, along with a kinematic model of the robot’s arm, beginning with very little information. The system starts by using exploratory motions to locate and centre the robot’s hand in the middle of its field of view, and then progressively builds the 3D and kinematic models. The system is flexible, and easy to integrate with different robots, because the model building process does not require any fiducial markers to be attached to the robot’s hand. To validate the models built by the system we perform a number of experiments. The results of the experiments demonstrate that the hand model built by the system can be tracked with a precision in the order of 1 mm, and that the kinematic model is accurate enough to reliably position the hand of the robot in camera space. 相似文献
192.
Esterification of acrylic acid with methanol by reactive chromatography: Experiments and simulations
The esterification of acrylic acid with methanol using Amberlyst 15 as a stationary phase has been investigated using a chromatographic reactor. Several experimental runs at various operating conditions have been conducted on a batch column. A classical reactive chromatography model including lumped kinetics, a linear driving force transport model and a heterogeneous kinetic model for the catalytic reaction has been developed. The additional dispersion of concentration fronts due to density gradient effects has been accounted for in the model. The model parameters have been determined in a fast and reliable way by directly fitting the batch column experiments. In general, a good agreement between experimental and calculated results is obtained. The evaluation of the covariance of the fitted model parameters reveals important insights about the system behavior.Based on the detailed batch column model, a complete model of a simulated-moving-bed reactor has been implemented and its optimal point of operation for the synthesis of methyl acrylate from acrylic acid has been determined. Particularly when considering the low-operating temperature, we can regard this process as a possible competition for current technologies. 相似文献
193.
《Journal of Process Control》2014,24(6):975-990
Soft sensor technology is an important means to estimate important process variables in real-time. Modeling for soft sensor system is the core of this technology. Most nonlinear dynamic modeling methods integrate the processes of building the dynamic and static relationships between secondary and primary variables, which limits the estimation accuracy for primary variables. To avoid the problem, a kind of soft sensor model consisting of a dynamic model in cascade with a static one is proposed. The model identification and update online are conducted in substep way. In order to improve the model update efficiency, two improved Gauss–Newton recursive algorithms, which avoid nonsingular covariance matrix, are proposed for time-invariant and time-variant soft sensor systems. The uniform convergence for dynamic model parameter and the existence of estimation deviations for static model parameters are proved for time-invariant soft sensor system. The parameters of time-variant soft sensor system would be boundedly convergent. Case study confirms that, on the basis of the proposed model and recursive algorithms, the dynamic and static characteristics of soft sensor system can be described efficiently, and the primary variables are ensured to be estimated accurately. 相似文献
194.
195.
Fault identification for process monitoring using kernel principal component analysis 总被引:2,自引:0,他引:2
In this research, we develop a new fault identification method for kernel principal component analysis (kernel PCA). Although it has been proved that kernel PCA is superior to linear PCA for fault detection, the fault identification method theoretically derived from the kernel PCA has not been found anywhere. Using the gradient of kernel function, we define two new statistics which represent the contribution of each variable to the monitoring statistics, Hotelling's T2and squared prediction error (SPE) of kernel PCA, respectively. The proposed statistics which have similar concept to contributions in linear PCA are directly derived from the mathematical formulation of kernel PCA and thus they are straightforward to understand. The main contribution of this work is that we firstly suggest a fault identification method especially applicable to process monitoring using kernel PCA. To demonstrate the performance, the proposed method is applied to two simulated processes, one is a simple nonlinear process and the other is a non-isothermal CSTR process. The simulation results show that the proposed method effectively identifies the source of various types of faults. 相似文献
196.
为了探究影响GH5家族β-甘露聚糖酶最适pH的各种因素,利用该酶的序列信息,构建了基于氨基酸组成的β-甘露聚糖酶理化性质与其最适pH的相关性模型。结果表明:该酶N端氨基酸序列是影响其最适pH的重要因素,在243个理化性质中有17个呈极显著相关,其中7个呈正相关。优化的转移能量参数相关性最高,为0.78:7个正相关的理化性质中,与螺旋相关的理化性质占3个。优化的转移能量参数和螺旋是影响pH稳定性的最重要的因素。所建立的模型为研究该酶酸碱适应性机理提供了一种简单有效的方法。 相似文献
197.
贺静 《计算机与应用化学》2014,(8):934-936
Volterra模型作为非线性领域的一种非线性模型,由于其对工业过程可以以任意精度逼近,使得该模型有很广泛的应用研究意义。在将该模型运用到实际控制系统中之前,模型的高精度辨识显得尤为重要。在以往针对Volterra模型的辨识算法中,基本上主要是采用通用辨识算法识别模型参数,比如最小二乘法及各种改进的最小二乘法。这些通用的辨识算法在辨识Volterra模型时,不能充分考虑其非线性特点,同样不能在辨识过程中充分利用该特点。本文在充分考虑Volterra模型非线性的前提下,提出了一种基于双阶跃信号输入的Volterra模型辨识算法,该算法辨识原理简单,计算量较小,论文最后将该辨识算法应用到典型非线性CSTR系统的的辨识中,辨识结果证明了算法的有效性。 相似文献
198.
针对纹理防伪标签在光线不足、视力不佳的情况下难以鉴别的问题,提出了一种基于DCT、感知哈希和视觉特征向量的纹理防伪标签鉴别算法.首先通过DCT和感知哈希提取图像的特征向量;然后建立特征数据库,通过特征向量之间的归一化相关系数(NC)实现纹理防伪标签的自动鉴别.实验结果表明,该方法可以有效抵抗常规攻击和几何攻击,可实现自动鉴别技术.与现有的纹理防伪技术相比,该算法可以减小占据的数据库存储空间,具有更好的实用性. 相似文献
199.
基于几何统计差异性的伪造印鉴识别方法 总被引:1,自引:0,他引:1
针对印鉴识别任务中有效印文的提取以及伪造印鉴的识别这两个难点问题,建立在监督分类体系下的印鉴识别系统.利用有效印文与背景的颜色统计差异以及真伪印鉴间的几何统计差异分别解决上述难点.在构建的包含3000个印鉴的印鉴数据库上进行实验,实验结果表明,该方法对于有效印文的提取准确率可达到(95.27±3.73%),对于伪造印鉴的识别准确率可达到97.62%,具有可行性和有效性. 相似文献
200.
为了能够识别多颗卫星故障,提高卫星导航定位系统的可靠性,提出了一种专门针对多故障情况的MHSS(多假设分组)算法。首先介绍了MHSS算法的基本原理,并对其仿真,表明其较传统算法更能满足更高导航完好性的需求;然后提出了MHSS-FDE改进算法,该算法与传统算法比较类似,需要计算检测门限进行有/无故障判决,将MHss方法中不受伪距测量影响的项排除,构造假设验证法的识别判别函数进行故障卫星识别;最后以多颗故障卫星条件为例对改进的MHSS-FDE算法故障识别率进行计算机仿真,并与现有的可用于多星故障识别的FDE算法进行仿真比较,结果显示:改进的MHSS-FDE算法具有较高的故障识别率。 相似文献