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51.
Ohad Gur Manav Bhatia William H. Mason Joseph A. Schetz Rakesh K. Kapania Taewoo Nam 《Structural and Multidisciplinary Optimization》2011,44(2):277-298
The paper describes the development of a multidisciplinary design optimization framework for conceptual design of truss-braced
wing configurations. This unconventional configuration requires specialized analysis tools supported by a modular and flexible
framework to accommodate different configurations. While the previous framework developed at Virginia Tech was a monolithic
Fortran-77 code, the need for more flexibility for complex truss-braced wing configurations was addressed by the development
of this new framework, which is based on Phoenix Integration ModelCenterTM environment. The framework uses updated structural and aerodynamic design modules that enable a more general geometry definition.
The new framework, thus, provides a foundation for future design concepts, especially multi-member truss-braced wing configurations.
The fuel saving potential of these truss-braced wing configurations is presented by comparing different truss designs with
gradually increased level of complexity. 相似文献
52.
Tien Van Do 《Acta Informatica》2010,47(1):67-75
In this paper we introduce the new M/M/1 retrial queue with working vacations which is motivated by the performance analysis
of a Media Access Control function in wireless systems. We give a condition for the stability of the model, which has an important
impact on setting the retrial rate for such systems. We derive the closed form solution in equilibrium for the retrial M/M/1
queue with working vacations, and we also show that the conditional stochastic decomposition holds for this model as well. 相似文献
53.
Yong‐Kyu Jang Seong Jun Lee Jae Young Lee Yi Li Jae Hoon Hwang Sang Woo Kim Chang Woo Shim Ju Yeon Seo Nam Jin Kim Yi Joon Ahn Nam Hee Kim Seon Hong Ahn Seong Ryong Lee Dae Hee Park Chi Woo Kim 《Journal of the Society for Information Display》2011,19(3):253-257
Abstract— A novel pixel design for vertical‐alignment LCDs with superior transmittance has been developed. The new liquid‐crystal mode, refered to as the hole‐induced vertical‐alignment mode (Hi‐VA), uses a via hole of an organic layer on a TFT substrate to achieve multi‐domain alignment. Compared to the conventional design, the Hi‐VA mode has a transmittance of up to 135% with a contrast ratio of 2000:1. Moreover, the new structure is free from ITO patterning or protrusion on the color‐filter side, which makes the fabrication process simple and low cost. 相似文献
54.
This article addresses the issue of visual landmark recognition in autonomous robot navigation along known routes, by intuitively
exploiting the functions of the human visual system and its navigational ability. A feedforward–feedbackward architecture
has been developed for recognising visual landmarks in real time. It integrates the theoretical concepts from the pre-attentive
and attentive stages in the human visual system, the selective attention adaptive resonance theory neural network and its
derivatives, and computational approaches towards object recognition in computer vision. The architecture mimics the pre-attentive
and attentive stages in the context of object recognition, embedding neural network processing paradigm into a computational
template-matching approach in computer vision. The real-time landmark recognition capability is achieved by mimicking the
pre-attentive stage, where it models a selective attention mechanism for optimal computational resource allocation, focusing
only on the regions of interest to address the computational restrictive nature of current computer processing power. Similarly,
the recognition of visual landmarks in both clean and cluttered backgrounds is implemented in the attentive stage by developing
a memory feedback modulation (MFM) mechanism that enables knowledge from the memory to interact and enhance the efficiency
of earlier stages in the architecture. Furthermore, it also incorporates both top-down and bottom-up facilitatory and inhibition
pathways between the memory and the earlier stages to enable the architecture to recognise a 2D landmark, which is partially
occluded by adjacent features in the surroundings. The results show that the architecture is able to recognise objects in
cluttered backgrounds using real-images in both indoor and outdoor scenes. Furthermore, the architecture application in autonomous
robot navigation has been demonstrated through a number of real-time trials in both indoor and outdoor environments. 相似文献
55.
Martijn H. A. Bonte Lionel Fourment Tien-tho Do A. H. van den Boogaard J. Huétink 《Structural and Multidisciplinary Optimization》2010,42(5):797-810
During the last decades, simulation software based on the Finite Element Method (FEM) has significantly contributed to the
design of feasible forming processes. Coupling FEM to mathematical optimization algorithms offers a promising opportunity
to design optimal metal forming processes rather than just feasible ones. In this paper Sequential Approximate Optimization (SAO) for optimizing forging processes is discussed. The algorithm
incorporates time-consuming nonlinear FEM simulations. Three variants of the SAO algorithm—which differ by their sequential
improvement strategies—have been investigated and compared to other optimization algorithms by application to two forging
processes. The other algorithms taken into account are two iterative algorithms (BFGS and SCPIP) and a Metamodel Assisted
Evolutionary Strategy (MAES). It is essential for sequential approximate optimization algorithms to implement an improvement
strategy that uses as much information obtained during previous iterations as possible. If such a sequential improvement strategy
is used, SAO provides a very efficient algorithm to optimize forging processes using time-consuming FEM simulations. 相似文献
56.
We present a new rapid prototyping method designed for simple fabrication of 3D microfluidics using a maskless direct writing technique on polymer substrates. The entire process is enabled by a commercial cutter plotter with 10 μm resolution precision and high speed. A CAD design of top and bottom microstructures is directly written on a polymer substrate using a cutter plotter after setting up the suitable force. The smallest channel width of 20 μm was obtained with the minimum force and 100 μm from the maximum. Also the written depth increased linearly with force from 30 to 130 μm. Several 3D microfluidic devices are demonstrated using a maskless writing technique. The entire fabrication process from CAD layout to a final 3D device can be completed in 30 min outside the clean room facilities. 相似文献
57.
Palanisamy GomathiAuthor VitaeMin Kwan KimAuthor Vitae Jung Je ParkAuthor VitaeDhanusuraman RagupathyAuthor Vitae Annamalai RajendranAuthor VitaeSoo Chool LeeAuthor Vitae Jae Chang KimAuthor VitaeSang Hak LeeAuthor Vitae Han Do GhimAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(2):897-902
Multiwalled carbon nanotubes (MWNTs) grafted chitosan (CS) nanowire (NW) was prepared by phase separation method. Glucose oxidase (GOx) was sequentially immobilized into MWNT-CS-NW to obtain MWNT-CS-NW/GOx biosensor. Field emission scanning electron microscopy (FESEM) images of MWNT-CS-NW/GOx reveals the existence of MWNT and CS. Cyclic voltammetry and amperometry were used to evaluate the electrochemical determination of glucose. The MWNT-CS-NW/GOx biosensor shows an excellent performance for glucose at +0.34 V with a high sensitivity (5.03 μA/mM) and lower response time (3 s) in a wide concentration range of 1-10 mM (correlation coefficient of 0.9988). In addition, MWNT-CS-NW/GOx biosensor possesses better reproducibility, storage stability and there is negligible interference from other electroactive components. 相似文献
58.
Nam Gyu ChoAuthor Vitae In-Sung HwangAuthor VitaeHo-Gi KimAuthor Vitae Jong-Heun LeeAuthor VitaeIl-Doo KimAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(1):366-371
This work presents a simple and versatile route to produce macroporous p-type metal oxide thin films. Two-dimensional arrays of p-type NiO films with a hollow hemisphere structure were fabricated by colloidal templating and RF-sputtering followed by a subsequent heat treatment. The diameter and shell thickness of the NiO hemisphere were 800 nm and 20 nm, respectively. X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the pure NiO phase with grain size of 10 nm was obtained at calcination temperatures that exceeded 450 °C. Close-packed arrays of hollow NiO hemispheres were found to exhibit p-type gas sensing properties against (CO, H2, C3H8, CH4, NO2, and C2H5OH), leading to significantly enhanced responses to C2H5OH (Rgas/Rair = 5.0 at 200 ppm). 相似文献
59.
Autonomous topological modeling of a home environment and topological localization using a sonar grid map 总被引:1,自引:0,他引:1
This paper presents a method of autonomous topological modeling and localization in a home environment using only low-cost
sonar sensors. The topological model is extracted from a grid map using cell decomposition and normalized graph cut. The autonomous
topological modeling involves the incremental extraction of a subregion without predefining the number of subregions. A method
of topological localization based on this topological model is proposed wherein a current local grid map is compared with
the original grid map. The localization is accomplished by obtaining a node probability from a relative motion model and rotational
invariant grid-map matching. The proposed method extracts a well-structured topological model of the environment, and the
localization provides reliable node probability even when presented with sparse and uncertain sonar data. Experimental results
demonstrate the performance of the proposed topological modeling and localization in a real home environment. 相似文献
60.
In this paper, an automatic diagnosis system for diabetes on Linear Discriminant Analysis (LDA) and Morlet Wavelet Support Vector Machine Classifier: LDA–MWSVM is introduced. The structure of this automatic system based on LDA-MWSVM for the diagnosis of diabetes is composed of three stages: The feature extraction and feature reduction stage by using the Linear Discriminant Analysis (LDA) method and the classification stage by using Morlet Wavelet Support Vector Machine (MWSVM) classifier stage. The Linear Discriminant Analysis (LDA) is used to separate features variables between healthy and patient (diabetes) data in the first stage. The healthy and patient (diabetes) features obtained in the first stage are given to inputs of the MWSVM classifier in the second stage. Finally, in the third stage, the correct diagnosis performance of this automatic system based on LDA–MWSVM for the diagnosis of diabetes is calculated by using sensitivity and specificity analysis, classification accuracy, and confusion matrix, respectively. The classification accuracy of this system was obtained at about 89.74%. 相似文献