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91.
92.
Ji-Hoon Choi Yong-Woon Park Jae-Bok Song In-So Kweon 《International Journal of Control, Automation and Systems》2011,9(4):716-725
GPS/INS integrated systems do not guarantee robustness and accuracy of localization, because GPS has vulnerability to external
disturbances. However, the overall performance and reliability of the system can be significantly improved by fusing multiple
sensors with a different operating principle. In outdoor environments where GPS may be blocked, there are many features compared
to the open space and these features can provide much information for UGV localization. Thus, this paper proposes an improved
localization algorithm based on the hierarchical federation of three measurement layers, i.e., GPS, INS, and visual localization,
to overcome the shortcomings of GPS/INS integrated systems. The proposed algorithm automatically switches the operation modes
according to GPS status and a network of a ground-based reference station. A vocabulary tree with SURF is used in the visual
localization method. In the data fusion of visual localization and INS, an asynchronous and time-delayed data fusion algorithm
is presented because visual localization is always time-delayed compared with INS. By using DGPS to obtain the reference position
under the dynamic conditions of the reference station, the restrictions of the conventional DGPS are overcome and all UGVs
within WiBro communication range of the reference station can accurately estimate the position with a common GPS. The experiment
results with a predefined path demonstrate enhancement of the robustness and accuracy of localization in outdoor environments. 相似文献
93.
The least squares support vector machine (LSSVM), like standard support vector machine (SVM) which is based on structural
risk minimization, can be obtained by solving a simpler optimization problem than that in SVM. However, local structure information
of data samples, especially intrinsic manifold structure, is not taken full consideration in LSSVM. To address this problem
and inspired by manifold learning technique, we propose a novel iterative least squares classifier, coined optimal locality
preserving least squares support vector machine (OLP-LSSVM). The idea is to combine structural risk minimization and locality
preserving criterion in a unified framework to take advantage of the manifold structure of data samples to enhance LSSVM.
Furthermore, inspired by the recent development of simultaneous optimization technique, adjacent graph of locality preserving
criterion is optimized simultaneously to give rise to improved discriminative performance. The resulting model can be solved
by alternating optimization method. The experimental results on several publicly available benchmark data sets show the feasibility
and effectiveness of the proposed method. 相似文献
94.
Esben Lindgaard Erik Lund 《Computer Methods in Applied Mechanics and Engineering》2010,199(37-40):2319-2330
The paper presents an approach to nonlinear buckling fiber angle optimization of laminated composite shell structures. The approach accounts for the geometrically nonlinear behaviour of the structure by utilizing response analysis up until the critical point. Sensitivity information is obtained efficiently by an estimated critical load factor at a precritical state. In the optimization formulation, which is formulated as a mathematical programming problem and solved using gradient-based techniques, a number of the lowest buckling factors are included such that the risk of “mode switching” during optimization is avoided. The presented optimization formulation is compared to the traditional linear buckling formulation and two numerical examples, including a large laminated composite wind turbine main spar, to clearly illustrate the pitfalls of the traditional formulation and the advantage and potential of the presented approach. 相似文献
95.
Resource service optimal-selection based on intuitionistic fuzzy set and non-functionality QoS in manufacturing grid system 总被引:4,自引:1,他引:3
In manufacturing grid (MGrid) system, according to functional requirements of a task, there exist a lot of resource services
which have similar functional characteristics. Multiple resource services with similar functional characteristics raise the
concern over resource service optimal-selection (RSOS). It is important to select the optimal resource service according to
their non-functionality characteristics or quality of service (QoS). However, QoS attributes are not easy to measure due to
their complexity and involvement of ill-structured information. In this study, user’s feeling is taken into account in RSOS
in an MGrid system. The non-functionality QoS evaluation of resource services is based on users’ feeling and transaction experiences
using intuitionistic fuzzy set (IFS). Furthermore, the dynamics of non-functionality QoS is considered, and a time-decay function
is introduced into non-functionality QoS evaluation. A new method is proposed for RSOS based on IFS and non-functionality
QoS, and the procedures are presented in detail. A practice case study is used to illustrate the proposed method and procedure.
The performance and advantage of the proposed method are discussed. 相似文献
96.
97.
Alexander I. Iliev Michael S. Scordilis João P. Papa Alexandre X. Falcão 《Computer Speech and Language》2010,24(3):445-460
A new method for the recognition of spoken emotions is presented based on features of the glottal airflow signal. Its effectiveness is tested on the new optimum path classifier (OPF) as well as on six other previously established classification methods that included the Gaussian mixture model (GMM), support vector machine (SVM), artificial neural networks – multi layer perceptron (ANN-MLP), k-nearest neighbor rule (k-NN), Bayesian classifier (BC) and the C4.5 decision tree. The speech database used in this work was collected in an anechoic environment with ten speakers (5 M and 5 F) each speaking ten sentences in four different emotions: Happy, Angry, Sad, and Neutral. The glottal waveform was extracted from fluent speech via inverse filtering. The investigated features included the glottal symmetry and MFCC vectors of various lengths both for the glottal and the corresponding speech signal. Experimental results indicate that best performance is obtained for the glottal-only features with SVM and OPF generally providing the highest recognition rates, while for GMM or the combination of glottal and speech features performance was relatively inferior. For this text dependent, multi speaker task the top performing classifiers achieved perfect recognition rates for the case of 6th order glottal MFCCs. 相似文献
98.
N. Lilić I. Obradović A. Cvjetić 《Engineering Applications of Artificial Intelligence》2010,23(4):453-462
Analysis of safety in surface coal mines represents a very complex process. Published studies on mine safety analysis are usually based on research related to accidents statistics and hazard identification with risk assessment within the mining industry. Discussion in this paper is focused on the application of AI methods in the analysis of safety in mining environment. Complexity of the subject matter requires a high level of expert knowledge and great experience. The solution was found in the creation of a hybrid system PROTECTOR, whose knowledge base represents a formalization of the expert knowledge in the mine safety field. The main goal of the system is the estimation of mining environment as one of the significant components of general safety state in a mine. This global goal is subdivided into a hierarchical structure of subgoals where each subgoal can be viewed as the estimation of a set of parameters (gas, dust, climate, noise, vibration, illumination, geotechnical hazard) which determine the general mine safety state and category of hazard in mining environment. Both the hybrid nature of the system and the possibilities it offers are illustrated through a case study using field data related to an existing Serbian surface coal mine. 相似文献
99.
Meysar Zeinali Amir Khajepour 《Engineering Applications of Artificial Intelligence》2010,23(8):1408-1419
The precision, performance, and robustness of model-based controllers depend, to a large extent, on the accuracy of the inverse dynamic model which is incorporated in the design of the controller. Due to complex nature of the laser cladding process and presence of time-varying uncertainties, derivation of an accurate mathematical inverse dynamic model of the process is very difficult, and involves many unknown parameters. The inverse dynamic model of the complex nonlinear laser cladding process, which is difficult to be described mathematically, can be described by a fuzzy logic-based inverse dynamic model constructed form input–output data. In this paper, the development of an adaptive fuzzy inverse dynamic model of the laser cladding process, using a systematic fuzzy modelling approach is presented. In a closed-loop laser cladding process, the scanning speed of the substrate is required to produce a clad with desired geometry and quality. In this paper, a fuzzy inverse dynamic model that describes the scanning speed as a function of the cladding parameters in particular the clad height is developed. The developed fuzzy model is validated by comparing the model output with experimental data. The results are very promising and show that fuzzy models can accurately describe the process dynamics. 相似文献
100.
The vehicle routing problem with simultaneous pickups and deliveries and time windows (VRP-SPDTW) is the problem of optimally integrating forward (good distribution) and reverse logistics (returning materials) for cost saving and environmental protection. We constructed a general mixed integer programming model of VRP-SPDTW. The model contained some classical vehicle routing problems as special cases. We proposed an improved differential evolution algorithm (IDE) for solving this problem. In the algorithm, we firstly adopted the novel decimal coding to construct an initial population, then used some improved differential evolution operators unlike the existing algorithm, and in mutation operation, we used an integer order criterion based on natural number coding method. We introduced a penalty technical to publish the infeasible solution. In addition, in the crossover operation, we designed a self-adapting crossover probability that varied with iteration. We did some numerical experiments, and the results showed that the proposed method is effective for solving VRP-SPDTW. 相似文献