全文获取类型
收费全文 | 276篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 62篇 |
金属工艺 | 1篇 |
机械仪表 | 5篇 |
建筑科学 | 21篇 |
矿业工程 | 1篇 |
能源动力 | 28篇 |
轻工业 | 36篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 22篇 |
一般工业技术 | 63篇 |
冶金工业 | 8篇 |
自动化技术 | 36篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 21篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 20篇 |
2012年 | 21篇 |
2011年 | 22篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有293条查询结果,搜索用时 15 毫秒
61.
Risat Mahmud Pathan 《Real-Time Systems》2014,50(4):509-547
The design and analysis of real-time scheduling algorithms for safety-critical systems is a challenging problem due to the temporal dependencies among different design constraints. This paper considers scheduling sporadic tasks with three interrelated design constraints: (i) meeting the hard deadlines of application tasks, (ii) providing fault tolerance by executing backups, and (iii) respecting the criticality of each task to facilitate system’s certification. First, a new approach to model mixed-criticality systems from the perspective of fault tolerance is proposed. Second, a uniprocessor fixed-priority scheduling algorithm, called fault-tolerant mixed-criticality (FTMC) scheduling, is designed for the proposed model. The FTMC algorithm executes backups to recover from task errors caused by hardware or software faults. Third, a sufficient schedulability test is derived, when satisfied for a (mixed-criticality) task set, guarantees that all deadlines are met even if backups are executed to recover from errors. Finally, evaluations illustrate the effectiveness of the proposed test. 相似文献
62.
In a continuing study of the preparation of ampholytic ionomers from the polymerization of ion-pair comonomers (cationic-anionic monomer pairs) with nonionic comonomers, the preparation of such ionomers from methyl methacrylate and n-butyl acrylate is described. For both systems, ionomers of varying ion contents were obtained. In the n-butyl acrylate system, a linear relationship of Tq vs. mol % ion content was found, but this did not occur for the methyl methacrylate ionomers. The solubilities of these materials in a wide variety of solvents is discussed. It appears that for n-butyl acrylate ionomers of high ion content in aqueous solution, a new form of polymeric surfactant is obtained. 相似文献
63.
This article presents the three-dimensional modeling of an induction motor using a magnetic equivalent circuit. The main goal of introducing the three-dimensional model is to include axial fluxes in the machine equations. Furthermore, enhancement of the precision of teeth flux estimation and air-gap permeances, as the most important and dominant factors, is another achievement of this model compared to that of the two-dimensional model. This increases the accuracy of the estimated torque. Although it is possible to include the impact of the bar skew in the two-dimensional modeling using a magnetic equivalent circuit, this can be included more precisely in the three-dimensional model due to the three-dimensional nature of the bar skew. Therefore, the three-dimensional model as an efficient method with rapid computations and suitable precision is used for modeling various types of eccentricity. It is shown that the three-dimensional model results are closer to the experimental results compared to that of the two-dimensional model. This confirms the merit of the three-dimensional model. Also, this method can be a proper substitution to the finite-element method in modeling a machine under fault and fault diagnosis. 相似文献
64.
Asgar Ali Mahmud Tengku Muda Muhammad Kamaruzaman Sijam Yasmeen Siddiqui 《International Journal of Food Science & Technology》2010,45(10):2134-2140
The in vitro and in vivo fungicidal activity of chitosan was studied against Colletotrichum gloeosporioides, the causal agent of anthracnose in papaya fruits. Chitosan at 1.5% and 2.0% concentrations showed a fungistatic effect with 90–100% inhibition (significant at P ≤ 0.05) of the fungal mycelial growth. Changes in the conidial morphology were also observed with the higher chitosan concentrations after 7‐ h incubation. In vivo studies showed that 1.5% and 2.0% chitosan coatings on papaya not only controlled the fruit decay but also delayed the onset of disease symptoms by 3–4 weeks during 5 weeks storage at 12 ± 1 °C and slowed down the subsequent disease development. However, when leaving the fruits to ripen at ambient temperature (28 ± 2 °C), 2.0% chitosan was less effective than 1.5% in controlling the disease development. Chitosan coatings also delayed the ripening process by maintaining the firmness levels, soluble solids concentration and titratable acidity values during and after storage. 相似文献
65.
66.
Siraje Arif Mahmud Keisuke Nagahisa Takashi Hirasawa Katsunori Yoshikawa Kengo Ashitani Hiroshi Shimizu 《Yeast (Chichester, England)》2009,26(1):17-30
To examine the effect of trehalose accumulation on response to saline stress in Saccharomyces cerevisiae, we constructed deletion strains of all combinations of the trehalase genes ATH1, NTH1 and NTH2 and examined their growth behaviour and intracellular trehalose accumulation under non‐stress and saline‐stress conditions. Saline stress was induced in yeast cells by NaCl addition at the exponential growth phase. All deletion strains showed similar specific growth rates and trehalose accumulation to their parent strain under non‐stress conditions. However, under the saline stress condition, one single deletion strain, nth1Δ, two double deletion strains, nth1Δ ath1Δ and nth1Δ nth2Δ, and the triple deletion strain nth1Δnth2Δ ath1Δ, all of which carry the nth1Δ deletion, showed increased trehalose accumulation as compared to the parent and other deletion strains. In particular, our statistical analysis revealed that the triple deletion strain showed a higher growth rate under the saline stress condition than the parent strain. Moreover, some deletion strains showed further trehalose accumulation under non‐stress conditions by overexpression of the TPS1 or TPS2 genes encoding the enzymes related to trehalose biosynthesis at the mid‐exponential phase. Such increased trehalose accumulation prior to NaCl addition could improve the growth of these strains under saline stress. Our results indicate that high trehalose accumulation prior to NaCl addition, rather than after NaCl addition, is necessary to achieve high growth activity under stress conditions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
67.
Osamah L. Barakat Shaiful J. Hashim Raja Syamsul Azmir B. Raja Abdullah Abdul Rahman Ramli Fazirulhisyam Hashim Khairulmizam Samsudin Mahmud Ab Rahman 《Journal in Computer Virology》2014,10(1):1-10
Nowadays, computer based technology has taken a central role in every person life. Hence, damage caused by malicious software (malware) can reach and effect many people globally as what could be in the early days of computer. A close look at the current approaches of malware analysis shows that the respond time of reported malware to public users is slow. Hence, the users are unable to get prompt feedback when reporting suspicious files. Therefore, this paper aims at introducing a new approach to enhance malware analyzer performance. This approach utilizes cloud computing features and integrates it with malware analyzer. To evaluate the proposed approach, two systems had been prepared carefully with the same malware analyzer, one of them utilizes cloud computing and the other left without change. The evaluation results showed that the proposed approach is faster by 23 % after processing 3,000 samples. Furthermore, utilizing cloud computing can open door to crowd-source this service hence encouraging malware reporting and accelerate malware detection by engaging the public users at large. Ultimately this proposed system hopefully can reduce the time taken to detect new malware in the wild. 相似文献
68.
For optical data storage applications, it is essential to determine the lowest intensity (also known as threshold intensity) below or at which no data page or grating can be recorded in the photosensitive material, as this in turn determines the data capacity of the material. Here, experiments were carried out to determine the threshold intensity below which the formation of a simple hologram--a holographic diffraction grating in a green-sensitized acrylamide-based photopolymer--is not possible. Two main parameters of the recording layers--dye concentration and thickness--were varied to study the influence of the density of the generated free radicals on the holographic properties of these layers. It was observed that a minimum concentration per unit volume of free radicals is required for efficient cross-linking of the created polymer chains and for recording a hologram. The threshold intensity below which no hologram can be recorded in the Erythrosin B sensitized layers with absorbance less than 0.16 was 50 μW/cm(2). The real-time diffraction efficiency was analyzed in the early stage of recording. It was determined that the minimum intensity required to obtain diffraction efficiency of 1% was 90 μW/cm(2), and the minimum required exposure was 8 mJ/cm(2). It was also determined that there is an optimum dye concentration of 1.5 × 10(-7) mol/L for effective recording above which no increase in the sensitivity of the layers is observed. 相似文献
69.
In this study, cost optimization of a composite floor system is performed utilizing the harmony search algorithm and an improved harmony search algorithm. These algorithms imitate the musical performance process that takes place when a musician searches for a better state of harmony, similar to the optimum design process which looks for the optimum solution. A composite floor system is designed by the LRFD-AISC method, using a unit consisting of a reinforced concrete slab and steel beams. The objective function is considered as the cost of the structure, which is minimized subjected to serviceability and strength requirements. Examples of composite floor systems are presented to illustrate the performance of the presented algorithms. 相似文献
70.