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排序方式: 共有464条查询结果,搜索用时 15 毫秒
1.
1.引言 在人工智能领域中,产生式系统是一种比较有效的知识表示方法,并得到了广泛应用。目前许多较为成功的专家系统都是用产生式系统实现的~[1]。随着应用领域的不断扩士其知识座的抓橄称渐增 相似文献
2.
Zheng Jiao Minghong Wu Jianzhong Gu Zheng Qin 《IEEE sensors journal》2003,3(4):435-438
Zinc ferrite is a promising sensor material. In this paper, thin films of nanocrystalline zinc ferrite were deposited on alumina substrates by nebulization of a 0.01-M solution of a mixture of ZnCl/sub 2/ and FeCl/sub 3/ in ethanol (Zn:Fe=1:2) followed by pyrolysis and annealing in flowing air. The resulting films were characterized by X-ray diffraction and scanning electron microscopy, and the gas-sensing properties of as-deposited films were also investigated. 相似文献
3.
Minghong Wang Zheng Liang Ziqiang Yang 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(6):1023-1033
Dispersion equation of planar-wiggler free-electron laser with background plasma is derived using linear fluid theory. The characteristic of this plasma FEL is analyzed in detail. It is shown that reasonable background plasma density tends to improve FEL growth rate. We also find there exits a critical plasma density for FEL operating. When the background plasma density is higher than critical density, the FEL can no longer be excited. 相似文献
4.
Stochastic analysis of file-swarming systems 总被引:1,自引:0,他引:1
File swarming (or file sharing) is one of the most important applications in P2P networks. In this paper, we propose a stochastic framework to analyze a file-swarming system under realistic setting: constraints in upload/download capacity, collaboration among peers and incentive for chunk exchange. We first extend the results in the coupon system [L. Massoulie, M. Vojnovic, Coupon replication systems, in: Proc. ACM SIGMETRICS, Banff, Alberta, Canada, 2005] by providing a tighter performance bound. Then we generalize the coupon system by considering peers with limited upload and download capacity. We illustrate the last-piece problem and show the effectiveness of using forward error-correction (FEC) code and/or multiple requests to improve the performance. Lastly, we propose a framework to analyze an incentive-based file-swarming system. The stochastic framework we propose can serve as a basis for other researchers to analyze and design more advanced features of file-swarming systems. 相似文献
5.
Juncong Lin Xing Gao Minghong Liao Jiazhi Xia Guilin Li Ying He 《Computers & Electrical Engineering》2014
Releasing sky lanterns is a popular way of celebrating festivals and ceremonies in the Asian countries. This paper presents a computer-aided approach to help novice users to design flyable sky lantern with desired shape. Given a closed up-right 3D model with a user-specified cutting on the bottom, our system optimizes the shape by regularizing the boundary, smoothing the geometry and improving the volume-to-area ratio to make it feasible for flying. The optimized shape is then approximated by a set of developable patches. Next, through a physical analysis step that tests the flying condition and determines the optimal size, the approximated shape is flattened into 2D patches, which can be printed out and glued together to form the airbag. Finally, the user can attach the airbag to a bamboo frame and assemble the fuel cell. We successfully apply our prototype system to design and construct real sky lanterns. 相似文献
6.
Floc architecture of bioflocculation sediment by ESEM and CLSM 总被引:1,自引:0,他引:1
Sediment flocculation is a critical component for the understanding of cohesive sediment dynamics. Traditionally, the referred study has largely been devoted to forming mechanism, influencing factors and physicochemical sediment conditions of all kinds of organic-flocculation and inorganic-flocculation. However, during the last decade, the bioflocculation of sediment by biological activity has been given increasing attention. But most studies have focused on the interrelations between biological and sedimentological variables. With the assistance of a newly developed field kit and correlative microscopy (which includes environmental scanning electron microscopy and confocal laser scanning microscopy), this article begins to bridge the resolution gap between sediment particles and biological activities as well as its metabolic products biofilm, in order to better understand the role of polymeric material biofilm in floc ultrastructure and outward floc behavior of bioflocculation sediment. Results have demonstrated that bioflocculation sediment was observed to be composed of complex networks of biofilm and appeared to be of complicated physical floc structures. The biofilm was found to embed particles and permeate the void space, representing the dominant physical bridging mechanism of the flocs and contributed to the extensive surface area, architecture characteristics, and mechanical properties of bioflocculation sediment. 相似文献
7.
Yu Gu Zheng Jiao Minghong Wu Bin Luo Yong Lei Yong Wang Lianzhou Wang Haijiao Zhang 《Nano Research》2017,10(1):121-133
The assembly of hybrid nanomaterials has opened up a new direction for the construction of high-performance anodes for lithium-ion batteries (LIBs). In this work, we present a straightforward, eco-friendly, one-step hydrothermal protocol for the synthesis of a new type of Fe2O3-SnO2/graphene hybrid, in which zero-dimensional (0D) SnO2 nanoparticles with an average diameter of 8 nm and one-dimensional (1D) Fe2O3 nanorods with a length of ~150 nm are homogeneously attached onto two-dimensional (2D) reduced graphene oxide nanosheets, generating a unique point-line-plane (0D-1D-2D) architecture. The achieved Fe2O3-SnO2/graphene exhibits a well-defined morphology, a uniform size, and good monodispersity. As anode materials for LIBs, the hybrids exhibit a remarkable reversible capacity of 1,530 mA·g?1 at a current density of 100 mA·g?1 after 200 cycles, as well as a high rate capability of 615 mAh·g?1 at 2,000 mA·g?1. Detailed characterizations reveal that the superior lithium-storage capacity and good cycle stability of the hybrids arise from their peculiar hybrid nanostructure and conductive graphene matrix, as well as the synergistic interaction among the components. 相似文献
8.
The natural calculation region in fluid dynamics involves complex boundaries. When using the Cartesian grid to approximate complex boundaries, two difficulties develop: the boundary zigzag effect and disagreement of direction of grid line and velocity. The multidimensional upwind scheme of the diagonal Cartesian method (DCM), using both Cartesian grid lines and diagonal lines segments, is presented in this paper to simulate the complex boundaries of the multiple-layer quasi 3D model equations. The DCM improves the simulation accuracy for the boundaries and calculation time increases only slightly compared to the Cartesian method. In order to verify the new scheme, a test case is presented which rotates the cavity flow at 45° to compare the numerical calculation results at different Reynolds numbers. The test case shows that the scheme is accurate and efficient in improving the simulation results. Then the three-dimensional advection-diffusion processes in the tidal water of the Hongyanhe Power Plant are simulated using this model. Numerical results show that the scheme is not only efficient on an experiment basis, but also efficient and reliable when applied to a large scale natural water area. 相似文献
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