全文获取类型
收费全文 | 872篇 |
免费 | 53篇 |
国内免费 | 17篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 239篇 |
金属工艺 | 28篇 |
机械仪表 | 31篇 |
建筑科学 | 41篇 |
矿业工程 | 3篇 |
能源动力 | 54篇 |
轻工业 | 64篇 |
水利工程 | 19篇 |
石油天然气 | 28篇 |
无线电 | 68篇 |
一般工业技术 | 190篇 |
冶金工业 | 26篇 |
原子能技术 | 14篇 |
自动化技术 | 123篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 25篇 |
2021年 | 48篇 |
2020年 | 37篇 |
2019年 | 52篇 |
2018年 | 84篇 |
2017年 | 56篇 |
2016年 | 67篇 |
2015年 | 38篇 |
2014年 | 49篇 |
2013年 | 105篇 |
2012年 | 58篇 |
2011年 | 54篇 |
2010年 | 55篇 |
2009年 | 36篇 |
2008年 | 24篇 |
2007年 | 17篇 |
2006年 | 18篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 2篇 |
2002年 | 12篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有942条查询结果,搜索用时 15 毫秒
1.
H. Safiri M. Ahmadi G.A. Jullien W.C. Miller 《The Journal of VLSI Signal Processing》2002,31(2):91-100
A new algorithm based on Genetic Programming (GP) for the problem of optimization of Multiple constant Multiplication (MCM) by Common Subexpression Elimination(CSE) is developed. This method is used for hardware optimization for DSP systems. A solution based on Genetic Programming is shown in this paper. The performance of the technique is demonstrated in one- and multi-dimensional digital filters with constant coefficients. 相似文献
2.
K. K. Gupta C. L. Lawson A. R. Ahmadi 《International journal for numerical methods in engineering》1992,33(8):1611-1623
The paper first presents the details of the development of a new six-noded plane triangular finite dynamic element. A block Lanczos algorithm is developed next for the accurate and efficient solution of the quadratic matrix eigenvalue problem associated with the finite dynamic element formulation. The resulting computer program fully exploits matrix sparsity inherent in such a discretization and proves to be most efficient for the extraction of the usually required first few roots and vectors, including repeated ones. Most importantly, the present eigenproblem solution effort is shown to be comparable to that of the corresponding finite element analysis, thereby rendering the associated dynamic element method rather attractive owing to superior convergence characteristics of such elements, presented herein. 相似文献
3.
Goodarz Ahmadi 《International Journal of Engineering Science》1985,23(1):1-25
A continuum theory for multiphase particulate suspensions in a fluid media is formulated. The generalized fundamental balance laws for the particulate phases as well as for the continuous suspending fluid phase are presented. The thermodynamics of a multiphase system is studied and the method of Lagrangian multipliers is employed to include the constraints of incompressibility of materials of the constituents and the criterion for fully saturated media. Constitutive equations are developed which include microrotational and microdilatational effects. The basic equations of motion of different phases are derived and discussed. Special considerations are given to the case of incompressible constituents. Examples of applications of the present theory to dilute suspension flows and multiphase sedimentations are also discussed. 相似文献
4.
Samar Shetaban Mir Mehdi Seyyed Esfahani Abbas Saghaei Abbas Ahmadi 《Computational Intelligence》2021,37(1):435-460
Today, air pollution, smoking, use of fatty acids and ready‐made foods, and so on, have exacerbated heart disease. Therefore, controlling the risk of such diseases can prevent or reduce their incidence. The present study aimed at developing an integrated methodology including Markov decision processes (MDP) and genetic algorithm (GA) to control the risk of cardiovascular disease in patients with hypertension and type 1 diabetes. First, the efficiency of GA is evaluated against Grey Wolf optimization (GWO) algorithm, and then, the superiority of GA is revealed. Next, the MDP is employed to estimate the risk of cardiovascular disease. For this purpose, model inputs are first determined using a validated micro‐simulation model for screening cardiovascular disease developed at Tehran University of Medical Sciences, Iran by GA. The model input factors are then defined accordingly and using these inputs, three risk estimation models are identified. The results of these models support WHO guidelines that provide medicine with a high discount to patients with high expected LYs. To develop the MDP methodology, policies should be adopted that work well despite the difference between the risk model and the actual risk. Finally, a sensitivity analysis is conducted to study the behavior of the total medication cost against the changes of parameters. 相似文献
5.
Hajipour Abdol R. Khorsandi Zahra Ahmadi Mehnoosh Jouypazadeh Hamidreza Mohammadi Bahareh Farrokhpour Hossein 《Catalysis Letters》2021,151(10):2842-2850
Catalysis Letters - Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds... 相似文献
6.
Javidan Kazemi Kordestani Ali Ahmadi Mohammad Reza Meybodi 《Applied Intelligence》2014,41(4):1150-1169
A new variant of Differential Evolution (DE), called ADE-Grid, is presented in this paper which adapts the mutation strategy, crossover rate (CR) and scale factor (F) during the run. In ADE-Grid, learning automata (LA), which are powerful decision making machines, are used to determine the proper value of the parameters CR and F, and the suitable strategy for the construction of a mutant vector for each individual, adaptively. The proposed automata based DE is able to maintain the diversity among the individuals and encourage them to move toward several promising areas of the search space as well as the best found position. Numerical experiments are conducted on a set of twenty four well-known benchmark functions and one real-world engineering problem. The performance comparison between ADE-Grid and other state-of-the-art DE variants indicates that ADE-Grid is a viable approach for optimization. The results also show that the proposed ADE-Grid improves the performance of DE in terms of both convergence speed and quality of final solution. 相似文献
7.
Hamed Ahmadi Saman Zad Tootaghaj Mahmoud Reza Hashemi Shervin Shirmohammadi 《Multimedia Systems》2014,20(5):485-501
The widespread availability of broadband internet access and the growth in server-based processing have provided an opportunity to run games away from the player into the cloud and offer a new promising service known as cloud gaming. The concept of cloud gaming is to render a game in the cloud and stream the resulting game scenes to the player as a video sequence over a broadband connection. To meet the stringent network bandwidth requirements of cloud gaming and support more players, efficient bit rate reduction techniques are needed. In this paper, we introduce the concept of game attention model (GAM), which is basically a game context-based visual attention model, as a means for reducing the bit rate of the streaming video more efficiently. GAM estimates the importance of each macro-block in a game frame from the player’s perspective and allows encoding the less important macro-blocks with lower bit rate. We have evaluated nine game video sequences, covering a wide range of game genre and a spectrum of scene content in terms of details, motion and brightness. Our subjective assessment shows that by integrating this model into the cloud gaming framework, it is possible to decrease the required bit rate by nearly 25 % on average, while maintaining a relatively high user quality of experience. This clearly enables players with limited communication resources to benefit from cloud gaming with acceptable quality. 相似文献
8.
The effect of electrostatic and capillary forces on bumpy particle adhesion and removal in turbulent flows is studied. We use the JKR theory and account for the increase of adhesion by capillary force. The effects of electrostatic forces and nonlinear hydrodynamic drag are included in the analyses. The criteria for incipient rolling and sliding detachments and electrostatic lifting removal are evaluated. A turbulence burst model is used for evaluating the peak air velocity near the substrate. The critical shear velocities for detaching particles of different sizes under different conditions are evaluated. The electric field strength needed for electrostatic removal of particles with different charges is also estimated. The results are compared with those obtained in the absence of the capillary force. Comparisons of the model predictions with the available experimental data are also presented. 相似文献
9.
Electropolymerization of pyrrole on lead substrate electrode was studied. Due to electrochemical activity of Pb in acidic media, this process is only possible at basic pHs. For this purpose, electropolymerization process was performed in an aqueous solution of Na2SO4 with pH 12. Potentiodynamic cycling shows the Pb oxidation at the first cycles. In subsequent cycles, polypyrrole film grows on the oxidized lead substrate. Of course, as the passive film is highly porous, a composite of polypyrrole/PbSO4 is formed in the first layers. However, subsequent cycling leads to the formation of pure polypyrrole film. According to this structure and strong connection of the polymer film to the substrate surface via this composite layer, the polypyrrole film deposited on the lead surface has enhanced mechanical stability. AFM measurements showed peculiar smoothness of both composite and lateral polypyrrole films. This synthesis approach is of particular interest for the preparation of highly stable polymer films and fabrication of supercapacitors with a polymer/PbSO4 conductive structure. 相似文献
10.
Behzad Biglarbegian Mohammad‐Reza Nezhad‐Ahmadi Amin Enayati Guy A. E. Vandenbosch Walter De Raedt Safieddin Safavi‐Naeini 《国际射频与微波计算机辅助工程杂志》2014,24(2):155-160
A new millimeter‐wave antenna structure on a low‐cost, production platform integrated passive device technology is presented. The antenna consists of a 2‐by‐1 array of slot antennas at 60 GHz. An in‐house developed on‐chip antenna measurement setup was used to characterize the fabricated antenna. The measurement results show an antenna gain of more than 5 dBi with a return loss of 18 dB at 60 GHz. The better‐than‐10‐dB impedance bandwidth of the antenna covers the 60‐GHz unlicensed band from 57 to 64 GHz. The 3‐dB beamwidths of the antenna are 105° and 76° at E‐plane and H‐plane at 60 GHz, respectively. The size of the die of the antenna is 2 mm × 4.5 mm. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:155–160, 2014. 相似文献