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81.
This paper investigates the changes that are required in networking technology for ‘everything over IP’ to become a reality.
Initially the changes that are taking place in the telecommunications industry are reviewed. This review ranges from a discussion
about the companies installing massive global IP networks to the emergence of novel routeing technologies, e.g. multi-protocol
label switching (MPLS) and terabit router technologies. The role of existing telecommunications operators is then discussed,
along with the reasons why they are developing interworking and intelligence layers based on distributed computing principles
to support all their networks — mobile, fixed, broadband and IP. 相似文献
82.
Karim Salahshoor Ehsan Safari Iraj Ahangari 《Engineering Applications of Artificial Intelligence》2013,26(5-6):1512-1531
This paper proposes a new adaptive nonlinear model predictive control (NMPC) methodology for a class of hybrid systems with mixed inputs. For this purpose, an online fuzzy identification approach is presented to recursively estimate an evolving Takagi–Sugeno (eTS) model for the hybrid systems based on a potential clustering scheme. A receding horizon adaptive NMPC is then devised on the basis of the online identified eTS fuzzy model. The nonlinear MPC optimization problem is solved by a genetic algorithm (GA). Diverse sets of test scenarios have been conducted to comparatively demonstrate the robust performance of the proposed adaptive NMPC methodology on the challenging start-up operation of a hybrid continuous stirred tank reactor (CSTR) benchmark problem. 相似文献
83.
Karim Salahshoor Sepide Zakeri Morteza Haghighat Sefat 《Engineering Applications of Artificial Intelligence》2013,26(8):1902-1910
Producing oil from gas-lift wells are often faced with severe producing oscillatory flow regimes. A major source of the oscillations is recognized as casing–heading instability which is caused by dynamic interaction between injection gas and multiphase fluid. This phenomenon poses strict production-related challenges in terms of lower average production and strain on downstream equipment. In this paper, an effective solution is proposed based on integration of an online interpretation dynamic model and a nonlinear model predictive control (NMPC) scheme. The paper uses adaptive growing and pruning radial basis function (GAP-RBF) neural networks (NNs) to recursively capture the essential dynamics of casing–heading instability in a nonlinear model structure. Extended Kalman filter (EKF) and unscented Kalman filter (UKF) are comparatively investigated to adaptively train modified GAP-RBF NNs. NMPC methodology is developed on the basis of the identified nonlinear NN model for real-time stabilization of casing–heading instability in an oil reservoir equipped with a gas-lift production well. A set of test studies has been conducted to explore the superior performance of the proposed adaptive NMPC controller under different scenarios for an oil reservoir simulated in ECLIPSE and linked to a complementary gas-lifted oil well simulated in programming environment. 相似文献
84.
Tatsuyuki Sagawa Etienne Boisnier Teruhisa Komatsu Karim Ben Mustapha Abdalla Hattour Naoko Kosaka 《International journal of remote sensing》2013,34(12):3051-3064
Remote sensing is widely used in coastal management. Lyzenga's model has been traditionally used to explain the relationship between bottom surface reflectance and the radiance level measured by satellite. Due to its central assumption, this model lacks accuracy compared with the other radiative transfer models. Nonetheless, it enables, with a single and simple equation, representation of the multiple optical processes taking place in coastal areas. Mapping processes associated with this model may include radiometric correction, a technique previously pointed out as a major driver of mapping accuracy. Radiometric correction is generally based on a depth-invariant index, efficient for clear waters (Jerlov water type I to II) but largely unsuitable when transparency decreases (Jerlov water type II to III). In order to overcome this problem, we developed a new index for radiometric correction, which combines bathymetry data with attenuation coefficients. The improved efficiency of our model with regard to the traditional depth invariant index was demonstrated through two case studies: Funakoshi Bay (Japan; Jerlov water type II) and the Gabes Gulf part located off Mahares (Tunisia; Jerlov water type II to III). 相似文献
85.
A New Look at the Power Method for Fast Subspace Tracking 总被引:1,自引:0,他引:1
Yingbo Hua Yong Xiang Tianping Chen Karim Abed-Meraim Yongfeng Miao 《Digital Signal Processing》1999,9(4):297
A class of fast subspace tracking methods such as the Oja method, the projection approximation subspace tracking (PAST) method, and the novel information criterion (NIC) method can be viewed as power-based methods. Unlike many non-power-based methods such as the Given's rotation based URV updating method and the operator restriction algorithm, the power-based methods with arbitrary initial conditions are convergent to the principal subspace of a vector sequence under a mild assumption. This paper elaborates on a natural version of the power method. The natural power method is shown to have the fastest convergence rate among the power-based methods. Three types of implementations of the natural power method are presented in detail, which require respectively O(n2p), O(np2), and O(np) flops of computation at each iteration (update), where n is the dimension of the vector sequence and p is the dimension of the principal subspace. All of the three implementations are shown to be globally convergent under a mild assumption. The O(np) implementation of the natural power method is shown to be superior to the O(np) equivalent of the Oja, PAST, and NIC methods. Like all power-based methods, the natural power method can be easily modified via subspace deflation to track the principal components and, hence, the rank of the principal subspace. 相似文献
86.
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88.
The effects of hydrogen (protium) or deuterium absorption∕desorption cycling on the strength and hardness of well-annealed palladium have been evaluated in this study. The results indicate that absorption followed by complete desorption of hydrogen or deuterium increases the strength and hardness characteristics of the palladium matrix while decreasing the metal's ductility. Increasing the amount of hydrogen or deuterium during absorption leads to more pronounced effects on the strength, hardness, and ductility of palladium. The effects of hydrogen absorption∕desorption are more pronounced than those of deuterium absorption∕desorption. The observed results have been explained in terms of the generation of dislocations during hydrogen or deuterium cycling. 相似文献
89.
Molecular quantum-dot cellular automaton (QCA) offers an alternative paradigm for computing at the nano-scale. QCA circuits
require an external clock which can be generated using a network of submerged electrodes to synchronize information flow and
provide the required power to drive the computation. In this paper, the effect of electrode separation and applied potential
on the likelihood of different QCA cell states of molecular cells located above and in between two adjacent electrodes is
analyzed. Using this analysis, estimates of operational ranges are developed for the placement, applied potential, and relative
phase between adjacent clocking electrodes to ensure that only those states that are used in the computation are energetically
favorable. Conclusions on the trade-off between cell size, cell-to-cell distance, and applied clocking potential are drawn
and the temperature dependence of the operation of fundamental QCA building blocks is considered. 相似文献