全文获取类型
收费全文 | 639篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 67篇 |
金属工艺 | 7篇 |
机械仪表 | 20篇 |
建筑科学 | 6篇 |
能源动力 | 36篇 |
轻工业 | 33篇 |
水利工程 | 1篇 |
石油天然气 | 9篇 |
无线电 | 182篇 |
一般工业技术 | 82篇 |
冶金工业 | 70篇 |
原子能技术 | 3篇 |
自动化技术 | 122篇 |
出版年
2023年 | 2篇 |
2022年 | 12篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 64篇 |
2012年 | 20篇 |
2011年 | 17篇 |
2010年 | 22篇 |
2009年 | 19篇 |
2008年 | 32篇 |
2007年 | 38篇 |
2006年 | 28篇 |
2005年 | 27篇 |
2004年 | 15篇 |
2003年 | 23篇 |
2002年 | 27篇 |
2001年 | 22篇 |
2000年 | 15篇 |
1999年 | 13篇 |
1998年 | 39篇 |
1997年 | 22篇 |
1996年 | 22篇 |
1995年 | 9篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 21篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有646条查询结果,搜索用时 15 毫秒
41.
In this paper, we develop an integrated model for the joint determination of both economic production quantity and level of preventive maintenance (PM) for an imperfect production process. This process has a general deterioration distribution with increasing hazard rate. The effect of PM activities on the deterioration pattern of the process is modelled using the imperfect maintenance concept. In this concept, it is assumed that after performing PM, the ageing of the system is reduced in proportion to the PM level. After a period of time in production, the process may shift to out-of-control states, either type I or type II. A minimal repair will remove the type I out-of-control state. If a type II out-of-control state occurs, the production process has to stop, and then restoration work is carried out. Examples of Weibull shock models are given to show that the use of PM reduces costs. 相似文献
42.
This paper presents a coordinated reverse logistics (CRL) management system for the treatment of multi-source hazardous wastes in a given region, in this case, a specific high-technology manufacturing zone. A linear multi-objective analytical model is formulated that systematically minimizes both the total reverse logistics operating costs and corresponding risks. In addition to inter-organizational logistics operating factors, environmental concerns are considered and formulated as corresponding risk-related constraints. Using the proposed model, results of numerical studies indicate that when the aspect of risk-induced penalties is not considered, the operational costs of regional hazardous-waste management can be efficiently reduced by 58%, compared to the existing operational costs at the study site. In addition, it is also observed that the corresponding weight associated with the risk-induced objective function embedded in the proposed model seems to have a significant effect on the CRL costs. 相似文献
43.
Chang Yuan-Ming Sung Chia-Yu Sheu Yu-Chien Yu Meng-Shiun Hsu Min-Yih Lee Jenq-Kuen 《The Journal of supercomputing》2021,77(9):10065-10096
The Journal of Supercomputing - With growing applications such as image recognition, speech recognition, ADAS, and AIoT, artificial intelligence (AI) frameworks are becoming popular in various... 相似文献
44.
Steve H. Jen Bing J. Sheu Yoichi Oshima 《Analog Integrated Circuits and Signal Processing》1997,12(2):107-118
A unified single-equation approach for the MOS transistordrain current modeling for energy-efficient submicron MOS circuitsis presented. Instead of three sets of separate equations forthe triode, saturation, and weak inversion regions, only a continuousexpression which is valid to describe the behavior of drain currentand the derivatives in all operation regions can be realizedby using a combination of hyperbola, sigmoid, and interpolationmethods. The model expression can predict accurate results forthe current, output conductance, and transconductance with continuousand smooth characteristics. The simulation results agree wellwith experimental data. 相似文献
45.
Hui-Yu Fang Uvarani Chokkalingam Shu-Fen Chiou Tsong-Long Hwang Shu-Li Chen Wei-Lung Wang Jyh-Horng Sheu 《International journal of molecular sciences》2015,16(1):736-746
A new chromene derivative, 2-(4'',8''-dimethylnona-3''E,7''-dienyl)-8-hydroxy-2,6-dimethyl-2H-chromene (1) together with four known natural products, methylfarnesylquinone (2), isololiolide (3), pheophytin a (4), and β-carotene (5) were isolated from the brown alga Homoeostrichus formosana. The structure of 1 was determined by extensive 1D and 2D spectroscopic analyses. Acetylation of 1 yielded the monoacetylated derivative 2-(4'',8''-dimethylnona-3''E,7''-dienyl)-8-acetyl-2,6-dimethyl-2H-chromene (6). Compounds 1–6 exhibited various levels of cytotoxic, antibacterial, and anti-inflammatory activities. Compound 2 was found to display potent in vitro anti-inflammatory activity by inhibiting the generation of superoxide anion (IC50 0.22 ± 0.03 μg/mL) and elastase release (IC50 0.48 ± 0.11 μg/mL) in FMLP/CB-induced human neutrophils. 相似文献
46.
47.
Taking advantage of the structure of logical representations, we report an algorithm that evaluates conjunctive queries in a massively parallel environment under an object-based representation for deductive databases. By distributing objects in a database, we show that parallel evaluation of a query can be achieved in a cooperative way so that the conventional tuple-by-tuple, operation-by-operation evaluation strategy can be replaced by a global, parallel matching approach. With the proposed scheme, all conjuncts of a given query can be examined at the same time, which enables us to eliminate the need of any temporary relation. On the other hand, compared with the interpretive method, we show that any data dependency imposed by shared variables is no longer a major problem in achieving AND-parallelism by the proposed scheme 相似文献
48.
In this article we consider the scalar transport governed by the convection-diffusion equation with linear production in two dimensions. The underlying idea in the development of a steady discretization scheme is to incorporate the analytical solution, obtained within a one-dimensional context, into the formulation. The method adopted here features exponential character in the weighted coefficients of the matrix equation, which generates a scheme with high accuracy. The analysis is followed by extending this discretization scheme to solve the convection-diffusion-production equation with a source term. In this article we present an analytical validation study of the method applied to two classes of model equations. Having verified that the method applies equally well for a transport scalar in either case with constant or variable flow velocity, we employ the one-dimensional scheme in the predictor and corrector steps to obtain the two-dimensional solution in an alternating direction-implicit fashion. The result obtained for the test considered in this article follows the trend of analytic data. 相似文献
49.
Abstract Numerical calculations are reported for the transient cooling of a solidified intrusion embedded in a water-saturated porous layer. Heat transfer rates are increased greatly when the intrusion undergoes thermal cracking as it cools. The effects of a uniform heat flux into the porous layer from below are considered. Solutions are obtained for porous layers that are initially above or below the critical-layer Rayleigh number for thermal convection. For conditions considered in this study, the effects on the cooling intrusion of initial convection and layer aspect ratio are small. Results are correlated by scaling velocities with the intrusion Rayleigh number. 相似文献
50.
A model for preventive maintenance operations and forecasting 总被引:1,自引:1,他引:1
Equipment costs constitute the greatest majority of overall costs for semiconductor manufacturing. Therefore, maintaining
high equipment availability has been regarded as one of the major goals in the industry. The ability to forecast correctly
equipment preventive maintenance (PM) timing requirements not only can help optimizing equipment uptime but also minimizing
negative impacts on manufacturing production efficiency. This research used grey theory and evaluation diagnosis to construct
a PM forecasting model for prediction of PM timing of various machines. The results showed significant improvements of PM
timing predictions compared to the existing method based on experience and an alternative method proposed by Li and Chang
(Semiconductor Manufacturing Technology Workshop 2002: 10–11, pp. 275–277) for the same fab cases.
Received: June 2005 / Accepted: December 2005 相似文献