全文获取类型
收费全文 | 723篇 |
免费 | 13篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 128篇 |
金属工艺 | 21篇 |
机械仪表 | 31篇 |
建筑科学 | 2篇 |
能源动力 | 18篇 |
轻工业 | 33篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
无线电 | 98篇 |
一般工业技术 | 147篇 |
冶金工业 | 91篇 |
原子能技术 | 9篇 |
自动化技术 | 159篇 |
出版年
2024年 | 2篇 |
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 23篇 |
2018年 | 24篇 |
2017年 | 29篇 |
2016年 | 25篇 |
2015年 | 7篇 |
2014年 | 21篇 |
2013年 | 50篇 |
2012年 | 22篇 |
2011年 | 30篇 |
2010年 | 28篇 |
2009年 | 29篇 |
2008年 | 22篇 |
2007年 | 29篇 |
2006年 | 18篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 17篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 19篇 |
1999年 | 18篇 |
1998年 | 32篇 |
1997年 | 24篇 |
1996年 | 20篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1954年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有747条查询结果,搜索用时 15 毫秒
711.
M. Venkatesh S. Patra K. Ramakrishnan G. Ray 《International journal of systems science》2018,49(12):2586-2600
This paper is concerned with the stability analysis of a linear system with interval time-varying delay using an augmented Lyapunov–Krasovskii (LK) functional approach. A delay-dependent stability criterion is developed in LMI framework to estimate the maximum allowable bound of the time-delay within which the system remains asymptotically stable in the sense of Lyapunov. Conservatism in the proposed delay-dependent stability analysis is reduced by introducing a new LK functional along with the Wirtinger's inequality and extended reciprocally convex matrix inequality. Finally, two numerical examples and the load frequency control problem have been solved to validate the superiority of the proposed stability criterion compared to existing literature. 相似文献
712.
713.
Wireless Personal Communications - A major issue in VANETs is the high mobility of the nodes. Broadcasting helps in improving the performance of the VANETs in terms of secure routing. However,... 相似文献
714.
Ramakrishnan M Nair Ray‐Yu Yang Warwick J Easdown Dil Thavarajah Pushparajah Thavarajah Jacqueline d'A Hughes JDH Keatinge 《Journal of the science of food and agriculture》2013,93(8):1805-1813
Mungbean (Vigna radiata (L.) R. Wilczek var. radiata) is one of the most important pulse crops grown in South, East and Southeast Asia. It provides significant amounts of protein (240 g kg?1) and carbohydrate (630 g kg?1) and a range of micronutrients in diets. Mungbean protein and carbohydrate are easily digestible and create less flatulence than proteins derived from other legumes. In addition, mungbean is lower in phytic acid (72% of total phosphorus content) than pigeonpea (Cajanus cajan L. Millsp.), soybean (Glycine max L.) and cereals; phytic acid is commonly found in cereal and legume crops and has a negative impact on iron and zinc bioavailability in plant‐based diets. Owing to its palatable taste and nutritional quality, mungbean has been used as an iron‐rich whole food source for baby food. The wide genetic variability of mineral concentrations (e.g. 0.03–0.06 g Fe kg?1, 0.02–0.04 g Zn kg?1) in mungbean indicates possibilities to improve its micronutrient content through biofortification. Therefore biofortification of existing mungbean varieties has great potential for enhancing the nutritional quality of diets in South and Southeast Asia, where protein and micronutrient malnutrition are among the highest in the world. This review paper discusses the importance of mungbean in agricultural production and traditional diets and the potential of enhancing the nutritional quality of mungbean through breeding and other means, including agronomic practices. © 2013 Society of Chemical Industry 相似文献
715.
S. Ramakrishnan M. Ferrando L. Aceña-Muñoz M. Mestres S. De Lamo-Castellví C. Güell 《Food and Bioprocess Technology》2014,7(7):1959-1972
Encapsulation of fish oil is an effective way to protect it against oxidation and masking its fishy odor. One of the possible ways to produce fish oil microcapsules is to produce an oil-in-water (O/W) emulsion followed by spray drying. This study compares the production of the O/W emulsion by mechanical homogenization (rotor–stator) with membrane emulsification and examines the effect of the type and amount of wall material added before drying. The membrane emulsification process selected for the emulsion production is premix membrane emulsification (ME), which consists of the production of a coarse emulsion by mechanical means followed by droplet breakup when the coarse emulsion is forced through a membrane. The emulsions produced had an oil load of 10 and 20 % and were stabilized using whey protein (isolate and hydrolyzate at 1 or 10 %) and sodium caseinate with concentrations of 2 and 10 %. Regarding the material used to build the microcapsule wall, whey protein, maltodextrin, or combinations of them were used at three different oil/wall ratios (1:1, 1:2, 1:3). The results clearly show that premix ME is a suitable technology for producing O/W emulsions stabilized with proteins, which have a smaller droplet size and are more monodisperse than those produced by rotor–stator emulsification. However, protein concentrations of 10 % are required to reduce the droplet size down to 2–3 μm. Small and monodisperse emulsions have been found to produce microcapsules with lower surface oil content, which increases oil encapsulation efficiency and presents lower levels of oxidation during storage at 30 °C. Of all the possible combinations studied, the one with the highest oil encapsulation efficiency is the production of a 20 % O/W emulsion stabilized with 10 % sodium caseinate followed by the addition of 50 % maltodextrin and drying. 相似文献
716.
In this paper, we consider the problem of robust stability for a class of linear systems with interval time-varying delay under nonlinear perturbations using Lyapunov-Krasovskii (LK) functional approach. By partitioning the delay-interval into two segments of equal length, and evaluating the time-derivative of a candidate LK functional in each segment of the delay-interval, a less conservative delay-dependent stability criterion is developed to compute the maximum allowable bound for the delay-range within which the system under consideration remains asymptotically stable. In addition to the delay-bi-segmentation analysis procedure, the reduction in conservatism of the proposed delay-dependent stability criterion over recently reported results is also attributed to the fact that the time-derivative of the LK functional is bounded tightly using a newly proposed bounding condition without neglecting any useful terms in the delay-dependent stability analysis. The analysis, subsequently, yields a stable condition in convex linear matrix inequality (LMI) framework that can be solved non-conservatively at boundary conditions using standard numerical packages. Furthermore, as the number of decision variables involved in the proposed stability criterion is less, the criterion is computationally more effective. The effectiveness of the proposed stability criterion is validated through some standard numerical examples. 相似文献
717.
A. M. Hermann C. Gonzalez P. A. Ramakrishnan D. Balzar N. Popa P. Rice C. H. Marshall J. N. Hilfiker T. Tiwald P. J. Sebastian M. E. Calixto R. N. Bhattacharya 《Solar Energy Materials & Solar Cells》2001,70(3)
This work reports the growth and characterization of thin films of Cu(In,Ga)Se2 (CIGS), which were grown by sequential sputtering, electrodeposition, and physical vapor deposition. Photovoltaic cells have been fabricated using these films with CdS heterojunction partners and the performance has been characterized. The effect of annealing conditions (temperature and duration) on the CIGS film microstructure and corresponding device performance has been investigated. Structure-property correlations were made using diffraction studies and Rietveld analysis. SEM studies were carried out to understand the effect of microstructure of the CIGS films on the solar cell efficiency. Cell efficiencies in excess of 10% have been achieved by using optimized annealing conditions. In addition, the optical properties of the sputtered CIGS films were characterized using variable angle spectroscopic ellipsometry and sputtered CIGS films were found to have optimum band gap. 相似文献
718.
719.
Dhananjay Mishra Clifford A. Shaffer Naren Ramakrishnan Layne T. Watson Kyung K. Bae Jian He Alex A. Verstak William H. Tranter 《Software》2007,37(14):1539-1558
This work describes the Site‐Specific System Simulator for Wireless System Design (S4W), a problem‐solving environment (PSE) that integrates visualization and computational tools with a high‐level graphical user interface. S4W improves the ability of wireless system engineers to design an indoor wireless system by encouraging them to think in terms of designing the system for optimal performance. Issues of computation management, data management, and location of resources are hidden from the user. The complex nature of data sets in the domain of wireless simulations calls for a customized set of visualization tools. Therefore, a number of ad hoc visualizations were developed for S4W. A study comparing the integrated system with an earlier, unintegrated version is presented. This helps to demonstrate the productivity gains that a PSE provides. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
720.
Summary The properties of guar seed oil (Cyammopsis Psoralioides) were studied, and it was found that it may be satisfactory for edible purposes. An interesting observation has been made
that the unsaponifiable fraction of guar oil may be used as a stabilizer for oils. 相似文献