全文获取类型
收费全文 | 2253篇 |
免费 | 63篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 46篇 |
综合类 | 1篇 |
化学工业 | 363篇 |
金属工艺 | 46篇 |
机械仪表 | 50篇 |
建筑科学 | 34篇 |
矿业工程 | 1篇 |
能源动力 | 72篇 |
轻工业 | 61篇 |
水利工程 | 5篇 |
无线电 | 533篇 |
一般工业技术 | 515篇 |
冶金工业 | 168篇 |
原子能技术 | 16篇 |
自动化技术 | 412篇 |
出版年
2023年 | 10篇 |
2022年 | 31篇 |
2021年 | 40篇 |
2020年 | 24篇 |
2019年 | 30篇 |
2018年 | 38篇 |
2017年 | 28篇 |
2016年 | 49篇 |
2015年 | 36篇 |
2014年 | 74篇 |
2013年 | 195篇 |
2012年 | 130篇 |
2011年 | 138篇 |
2010年 | 105篇 |
2009年 | 109篇 |
2008年 | 143篇 |
2007年 | 90篇 |
2006年 | 88篇 |
2005年 | 82篇 |
2004年 | 77篇 |
2003年 | 73篇 |
2002年 | 59篇 |
2001年 | 59篇 |
2000年 | 51篇 |
1999年 | 63篇 |
1998年 | 84篇 |
1997年 | 61篇 |
1996年 | 69篇 |
1995年 | 34篇 |
1994年 | 38篇 |
1993年 | 29篇 |
1992年 | 21篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有2323条查询结果,搜索用时 15 毫秒
81.
Chia-Hsiung Kao Chun-Chieh Tseng Fong-Ming Lee Mao-Fu Lai 《Advanced Packaging, IEEE Transactions on》2006,29(1):140-148
A useful and rather new simulation technique for connectors up to 6.25 GHz is presented and discussed in this paper. The proposed model extracts electrical parameters of a connector using time-domain reflectometry (TDR) measurements. A new technique was developed to obtain accurate impedance profiles using TDR and a multisegment approach that is effectively a distributed coupled model. The parameter extraction and characterization of connectors are discussed. The performance of the proposed segmented transmission line model is verified by simulation of the model in SPICE and by experimental measurement. The results show that the proposed model can simulate the electrical characteristics, including crosstalk and impedance, of high-density and high-speed connectors with satisfactory accuracy. Based on the proposed modeling and CAD simulators, the design and analysis of complicated high-density and high-speed connectors can be executed accurately and effectively. Compared with other previous models, the proposed model can significantly improve the accuracy of simulation. 相似文献
82.
Yi-Cheng Liou Chi-Ting Wu Ko-Hao Tseng Tzu-Chin Chung 《Materials Research Bulletin》2005,40(9):1483-1489
Synthesis of BaTi4O9 ceramics by a reaction-sintering process was investigated. The mixture of raw materials for stoichiometric BaTi4O9 were pressed and sintered into ceramics without any calcination stage involved. Pure BaTi4O9 phases were obtained at 1150-1280 °C. High-sintered density, 98.2-99.5% of theoretical value (4.533 g/cm3), can be obtained for pellets sintered at 1200-1280 °C for 2-6 h. Some rod-shaped grains 3-7 μm in the longitudinal axis appear in pellets sintered at 1230 °C. Both the size and the amount of these rod-shaped grains increase at higher sintering temperature. 相似文献
83.
Yen-Shin Lai Fu-San Shyu Shian Shau Tseng 《Industry Applications, IEEE Transactions on》2003,39(2):485-491
This paper presents a new detection technique of initial position for a three-phase brushless DC motor which does not require any current and position sensors, and thereby significantly reduces the cost. The fundamental principle of the technique is to determine the initial position of the permanent magnet by the time periods of discharge of stator windings, which are excited before discharge. As compared to previous approaches, the presented technique does not cause any rotation during detection, and it is therefore very promising for particular kinds of applications, which do not allow the motor to rotate potentially in the wrong direction during initial position detection, e.g., electrical vehicles. As compared to earlier techniques, the presented technique dramatically simplifies the detection procedures and cost. Experimental results derived from a field-programmable gate-array-based control system are presented to demonstrate the feasibility of the presented technique. 相似文献
84.
Shu-Feng Tseng 《Decision Support Systems》1997,20(4):357-383
Diverse reasoning supports a dynamic integration of various reasoning methods in a computerized system. This paper describes a control blackboard approach to simulate the control features observed in the expert's model formulation protocols. The diverse reasoning concept is incorporated so that the model formulation process is dynamically in a plan-directed, action-directed, or data-directed fashion. The diverse reasoning concept facilitates the control features simulation. By analyzing the diverse reasoning behavior in the proposed system, this paper contributes to a better understanding of and support to the modeling process for the design of intelligent decision support systems. The usefulness of the prototype system is also evaluated using an empirical experiment. 相似文献
85.
Product family modeling for mass customization 总被引:64,自引:0,他引:64
Jianxin Jiao Mitchell M. Tseng Vincent G. Duffy Fuhua Lin 《Computers & Industrial Engineering》1998,35(3-4):495-498
With growing reliance on modeling in product development, it is imperative to describe product families in a cohesive way. In particular, mass customization calls for a close integration of product life cycle from customer recognition to delivery and services. This paper proposes a triple-view scheme for modeling product families. Technical challenges are discussed by comparing product family modeling with modeling single products. Individual modeling formalisms for different views are discussed. An example of product family modeling in power supply design is presented to illustrate the feasibility and potential of the proposed approach. 相似文献
86.
87.
Kevin K. Tseng 《Canadian Metallurgical Quarterly》2004,130(5):547-550
Many materials exhibit elasto–visco–plastic behavior when subjected to loadings with certain strain rate. Examples include natural materials such as metals, clays, and soils and manmade materials such as some biomimic materials. Some voids may exist or be introduced in these materials. The effects of the voids on the material response are important in predicting the strength, reliability, and service life of structural systems containing these materials. This paper presents the results of applying a statistical micromechanical approach to describe the macroscopic behavior of elasto–visco–plastic materials containing many randomly dispersed spherical voids. Most existing micromechanics based models are only applicable to monotonic proportional loadings. The limitation is removed by integrating the material model into the framework of continuum plasticity. With the discrete integration algorithm and local return mapping algorithm, the proposed computation method is applicable to any loading and unloading histories and is ready for implementing into finite element analysis. 相似文献
88.
The orthogonal neural network is a recently developed neural network based on the properties of orthogonal functions. It can avoid the drawbacks of traditional feedforward neural networks such as initial values of weights, number of processing elements, and slow convergence speed. Nevertheless, it needs many processing elements if a small training error is desired. Therefore, numerous data sets are required to train the orthogonal neural network. In the article, a least‐squares method is proposed to determine the exact weights by applying limited data sets. By using the Lagrange interpolation method, the desired data sets required to solve for the exact weights can be calculated. An experiment in approximating typical continuous and discrete functions is given. The Chebyshev polynomial is chosen to generate the processing elements of the orthogonal neural network. The experimental results show that the numerical method in determining the weights gives as good performance in approximation error as the known training method and the former has less convergence time. © 2004 Wiley Periodicals, Inc. Int J Int Syst 19: 1257–1275, 2004. 相似文献
89.
90.
Yun-Han Su Cheng-Tang Pan Yu-Sheng Tseng Ji Zhang Wen-Fan Chen 《Ceramics International》2021,47(14):19414-19423
Cerium (Ce)-substituted diopsides (CaMgSi2O6) with enhanced mechanical strength and bioactivity were fabricated by precipitation method, followed by annealing at 1000 °C for 4 h. The mineralogical, morphological, in vitro biomineralization, degradation, and mechanical properties were investigated in order to assess the factors and mechanisms affecting the resultant properties. The X-ray diffractometer results showed that the onset of substitutional solid solubility in 0.25 mol Ce would result in new phase formation (cerium dioxide [CeO2], and magnesium silicate [MgSiO3]) further causing lattice instability. With increasing Ce dopant levels to 1.00 mol, the initial CaMgSi2O6 phase was completely replaced by new phases. The field-emission scanning electron microscopy results indicated that the 0.25 mol Ce had the best biomineralization performance in vitro, while less hydroxyapatite precipitates were found with further increasing Ce dopant levels, suggesting the new phases led to the hindrance of precipitates. The weight loss values indicated that the high dissolution rate of ions in the matrix was observed in the pure sample, while the high readsorption rate of ions in the simulated body fluid (SBF) occurred with increasing Ce dopant levels. The pH value and the inductively coupled plasma-mass spectrometer results suggested that the release of Ca and Mg ions controlled the pH value. The mechanical strength of matrices before SBF immersion was related to the phase transformation, the elastic modulus of CeO2 and CaMgSi2O6, and the release of Mg ions, while the mechanical strength of matrices after SBF immersion was dominated by the structure of matrices. 相似文献