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961.
The Pt–Si binary system was thermodynamically assessed using the CALPHAD method based on the available experimental data from the literature. The solution phases, including Liquid, Fcc_A1 (Pt) and Diamond_A4 (Si), were treated as substitutional solution phases, of which the excess Gibbs energies were expressed with Redlich–Kister polynomial functions. Meanwhile, the intermetallic compounds, PtSi, Pt6Si5, Pt2Si, Pt17Si8, Pt5Si2, Pt3Si and Pt25Si7, were modeled as stoichiometric compounds. Subsequently, a set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases were obtained and the calculated values of phase diagram and thermodynamics were found to be in reasonable agreement with experimental data. 相似文献
962.
The conventional fault-tolerant sensor systems would fail when outputs from incorporated sensors are either noisy or drifting. This paper presents a novel real-time fault compensation method, which uses state estimation and compensation techniques, that the sensor system can perform robust measurements even when outputs from every incorporated sensor are noisy and drifting. In a simulation example, the proposed design can detect and correct the sensor errors (dc bias and drift) in real time. For the dc bias, the minimum detectable offset value is 0.1, which is the same as the standard deviation of the sensor noise. The compensated sensor output is biased at values smaller than 0.02. For the sensor drifts, the proposed method can compensate drifts for the change rate of drifts up to four times faster than that of the signal to be measured. The highest change rate of drifts, that can be compensated by this method, is determined by the standard deviation of the sensor noise. 相似文献
963.
This paper describes the design and modelling of ultrasonic tomography for two-component high-acoustic impedance mixture such as liquid/gas and oil/gas flow which commonly found in chemical columns and industrial pipelines. The information obtained through this research has proven to be useful for further development of ultrasonic tomography. This includes acquiring and processing ultrasonic signals from the transducers to obtain the information of the spatial distributions of liquid and gas in an experimental column. Analysis on the transducers’ signals has been carried out to distinguish between the observation time and the Lamb waves. The information obtained from the observation time is useful for further development of the image reconstruction. 相似文献
964.
The aircraft lap joints are inspected with an enhanced visual inspection technique named “Edge of Light”, which is patented
by the NRC Institute for Aerospace Research. This technique is applicable for rapid detection of possible hidden corrosion
in lap joints. The surface deformation due to hidden corrosion can be characterized by this optical-based inspection method.
In this study, a calibration procedure is developed to quantify the lap joint surface deformation. The effect of surface reflectivity
is investigated with the solid film highlighting technique (SolidHiTM), which helps achieve a uniform reflectivity during the inspection. The efficiency of the technique is demonstrated with
the experimental results.
This work is supported by NRC-IAR New Initiative Research Funding. 相似文献
965.
A. Z. Kouzani 《Machine Vision and Applications》2008,19(4):223-248
There has been an increasing interest in face recognition in recent years. Many recognition methods have been developed so
far, some very encouraging. A key remaining issue is the existence of variations in the input face image. Today, methods exist
that can handle specific image variations. But we are yet to see methods that can be used more effectively in unconstrained
situations. This paper presents a method that can handle partial translation, rotation, or scale variations in the input face
image. The principal is to automatically identify objects within images using their partial self-similarities. The paper presents
two recognition methods which can be used to recognise objects within images. A face recognition system is then presented
that is insensitive to limited translation, rotation, or scale variations in the input face image. The performance of the
system is evaluated through four experiments. The results show that the system achieves higher recognition rates than those
of a number of existing approaches.
The author would like to thank the Australian Research Council (ARC) which supports this research with a Discovery Grant. 相似文献
966.
An automatic road sign recognition system first locates road signs within images captured by an imaging sensor on-board of
a vehicle, and then identifies the detected road signs. This paper presents an automatic neural-network-based road sign recognition
system. First, a study of the existing road sign recognition research is presented. In this study, the issues associated with
automatic road sign recognition are described, the existing methods developed to tackle the road sign recognition problem
are reviewed, and a comparison of the features of these methods is given. Second, the developed road sign recognition system
is described. The system is capable of analysing live colour road scene images, detecting multiple road signs within each
image, and classifying the type of road signs detected. The system consists of two modules: detection and classification.
The detection module segments the input image in the hue-saturation-intensity colour space, and then detects road signs using
a Multi-layer Perceptron neural-network. The classification module determines the type of detected road signs using a series
of one to one architectural Multi-layer Perceptron neural networks. Two sets of classifiers are trained using the Resillient-Backpropagation
and Scaled-Conjugate-Gradient algorithms. The two modules of the system are evaluated individually first. Then the system
is tested as a whole. The experimental results demonstrate that the system is capable of achieving an average recognition
hit-rate of 95.96% using the scaled-conjugate-gradient trained classifiers. 相似文献
967.
968.
Zafer Iscan Ayhan Yüksel Zümray Dokur Mehmet Korürek Tamer Ölmez 《Digital Signal Processing》2009,19(5):890-901
In this study, a novel incremental supervised neural network (ISNN) is proposed for the segmentation of medical images. Performance of the ISNN is investigated for tissue segmentation in medical images obtained from various imaging modalities. Two feature extraction methods based on transform and moments are comparatively investigated to segment the tissues in medical images. Two-dimensional (2D) continuous wavelet transform (CWT) and the moments of the gray-level histogram (MGH) are computed in order to form the feature vectors of ultrasound (US) bladder and phantom images, X-ray computerized tomography (CT) and magnetic resonance (MR) head images. In the 2D-CWT method, feature vectors are formed by the intensity of one pixel of each wavelet-plane of different energy bands. The MGH represents the tissues within the sub-windows by using the spatial variation of image intensities. In this study, the ISNN and Grow and Learn (GAL) network are employed for the segmentation task. It is observed that the ISNN has significantly eliminated the disadvantages of the GAL network in the segmentation of the medical images. 相似文献
969.
Kaiser K.A. Gebraeel N.Z. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2009,39(4):840-849
This paper presents a sensory-updated degradation-based predictive maintenance policy (herein referred to as the SUDM policy). The proposed maintenance policy utilizes contemporary degradation models that combine component-specific real-time degradation signals, acquired during operation, with degradation and reliability characteristics of the component's population to predict and update the residual life distribution (RLD). By capturing the latest degradation state of the component being monitored, the updating process provides a more accurate of the remaining life. With the aid of a stopping rule, maintenance routines are scheduled based on the most recently updated RLD. The performance of the proposed maintenance policy is evaluated using a simulation model of a simple manufacturing cell. Frequency of unexpected failures and overall maintenance costs are computed and compared with two other benchmark maintenance policies: a reliability-based and a conventional degradation-based maintenance policy (without any sensor-based updating). 相似文献
970.
In this article, the adaptive integral method (AIM) is used to analyze large‐scale planar structures. Discretization of the corresponding integral equations by method of moment (MoM) with Rao‐Wilton‐Glisson (RWG) basis functions can model arbitrarily shaped planar structures, but usually leads to a fully populated matrix. AIM could map these basis functions onto a rectangular grid, where the Toeplitz property of the Green's function would be utilized, which enables the calculation of the matrix‐vector multiplication by use of the fast Fourier transform (FFT) technique. It reduces the memory requirement from O(N2) to O(N) and the operation complexity from O(N2) to O(N log N), where N is the number of unknowns. The resultant equations are then solved by the loose generalized minimal residual method (LGMRES) to accelerate iteration, which converges much faster than the conventional conjugate gradient method (CG). Furthermore, several preconditioning techniques are employed to enhance the computational efficiency of the LGMRES. Some typical microstrip circuits and microstrip antenna array are analyzed and numerical results show that the preconditioned LGMRES can converge much faster than conventional LGMRES. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. 相似文献