全文获取类型
收费全文 | 401篇 |
免费 | 13篇 |
专业分类
电工技术 | 23篇 |
综合类 | 2篇 |
化学工业 | 62篇 |
金属工艺 | 2篇 |
机械仪表 | 6篇 |
建筑科学 | 38篇 |
能源动力 | 9篇 |
轻工业 | 79篇 |
水利工程 | 1篇 |
无线电 | 23篇 |
一般工业技术 | 39篇 |
冶金工业 | 49篇 |
原子能技术 | 11篇 |
自动化技术 | 70篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 4篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 16篇 |
2012年 | 15篇 |
2011年 | 21篇 |
2010年 | 12篇 |
2009年 | 23篇 |
2008年 | 18篇 |
2007年 | 24篇 |
2006年 | 13篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1994年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1985年 | 3篇 |
1984年 | 14篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1970年 | 4篇 |
1969年 | 13篇 |
1967年 | 4篇 |
1943年 | 8篇 |
1942年 | 11篇 |
1941年 | 6篇 |
1919年 | 2篇 |
1918年 | 2篇 |
1914年 | 3篇 |
排序方式: 共有414条查询结果,搜索用时 15 毫秒
1.
In this paper, we describe RanGen, a random network generator for generating activity-on-the-node networks and accompanying data for different classes of project scheduling problems. The objective is to construct random networks which satisfy preset values of the parameters used to control the hardness of a problem instance. Both parameters which are related to the network topology and resource-related parameters are implemented. The network generator meets the shortcomings of former network generators since it employs a wide range of different parameters which have been shown to serve as possible predictors of the hardness of different project scheduling problems. Some of them have been implemented in former network generators while others have not. 相似文献
2.
Henk A. van der Schee Willy B. H. Kennedy Jan-Paul Bouwknegt Renske Hittenhausen-Gelderblom 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,188(1):11-15
Summary Linear discriminant analysis of GLC-aromagram data is used to separate several classes of wine distillates, namely cognac, armagnac and brandy. In this paper we demonstrate how this method was used to detect adulteration. The adulteration was confirmed by the presence of ethyl heptanoate and limonene, which are well-known flavour compounds. They were analysed by means of a Purge and Trap headspace technique. Mass spectrometry was used to identify these flavours.
Ein Beispiel für die Verfälschung von Cognac
Zusammenfassung Die Linear-Discriminanz-Analyse von GLC-Aromagramm-Daten wird zur Klassifizierung von Weindestillaten wie Cognac, Armagnac und Brandy verwendet. In dieser Arbeit werden mit dieser Methode Verfälschungen nachgewiesen, die durch die Gegenwart der Ethylester der Heptansäure und des Limonen belegt werden konnten. Diese Substanzen wurden mit der Purge- und Trap-Methode erfaßt und massenspektrometrisch identifiziert.相似文献
3.
4.
Jinguang Han Willy Susilo Yi Mu Jun Yan 《International Journal of Information Security》2012,11(6):389-401
Oblivious signature-based envelope (OSBE) schemes have demonstrated their potential applications in the protection of users privacy and rights. In an OSBE protocol, an encrypted message can only be decrypted by the receiver who holds a valid signature on a public message, while the sender (encrypter) does not know whether the receiver has the signature or not. Our major contributions in this work lie in the following aspects. We improve the notion of OSBE so that a valid credential holder cannot share his/her credential with other users (i.e., all-or-nothing non-transferability). We clarify the relationship between one-round OSBE and identity-based encryption (IBE) and show that one-round OSBE and semantically secure IBE against the adaptively chosen identity attack (IND-ID-CPA) are equivalent, if the signature in the OSBE scheme is existentially unforgeable against adaptively chosen message attacks. We propose an oblivious access control scheme to protect user privacy without the aid of any zero-knowledge proof. Finally, we also highlight some other novel applications of OSBE, such as attributed-based encryption. 相似文献
5.
Shams Qazi Raad Raad Yi Mu Willy Susilo 《Journal of Network and Computer Applications》2013,36(2):582-592
A wormhole attack is one of the hardest problems to detect whereas it can be easily implanted in any type of wireless ad hoc network. A wormhole attack can easily be launched by the attacker without having knowledge of the network or compromising any legitimate nodes. Most existing solutions either require special hardware devices or make strong assumptions in order to detect wormhole attacks which limit the usability of these solutions. In this paper, we present a security enhancement to dynamic source routing (DSR) protocol against wormhole attacks for ad hoc networks which relies on calculation of round trip time (RTT). Our protocol secures DSR against a wormhole attack in ad hoc networks for multirate transmissions. We also consider the processing and queuing delays of each participating node in the calculation of RTTs between neighbors which to date has not been addressed in the existing literature. This work provides two test cases that show that not taking multirate transmission into consideration results in miss identifying a wormhole attack. 相似文献
6.
The multi-mode resource-constrained project scheduling problem (MRCPSP) involves the determination of a baseline schedule of the project activities, which can be executed in multiple modes, satisfying the precedence relations and resource constraints while minimizing the project duration. During the execution of the project, the baseline schedule may become infeasible due to activity duration and resource disruptions. We propose and evaluate a number of dedicated exact reactive scheduling procedures as well as a tabu search heuristic for repairing a disrupted schedule, under the assumption that no activity can be started before its baseline starting time. We report on promising computational results obtained on a set of benchmark problems. 相似文献
7.
8.
Glycoproteinoses, Pompe disease, and sialic acid storage diseases are characterized by a massive accumulation of unprocessed oligosaccharides and/or glycoconjugates in urine. The identification of these glycocompounds is essential for a proper diagnosis. In this study, we investigated the potential of MALDI‐TOF‐MS to identify glycocompounds present in urine from patients with different inborn errors of glycan metabolism. Urinary glycocompounds were permethylated, and analyzed using GC‐MS and MALDI‐TOF‐MS. In order to confirm tentative assignments, a second aliquot of urine was purified on a C18 Sep‐Pak cartridge and glycocompounds were desalted on a column of nonporous graphitized carbon. The glycocompounds were then sequentially on‐plate digested using an array of exoglycosidases. A range of disease‐specific oligosaccharides as well as glycopeptides was identified for all oligosacchariduria models. In addition, free sialic acid accumulated in urine from a patient suffering from French‐type sialuria, has been detected by a GC‐MS approach, which could be applied to other sialic acid storage diseases. This procedure is simple, and can be performed in few simple steps in less than 24 h. This current method can be applied for newborn screening for other inherited metabolic diseases as well as for assessing treatments in clinical trials. 相似文献
9.
10.
Vansteenkiste Maarten; Zhou Mingming; Lens Willy; Soenens Bart 《Canadian Metallurgical Quarterly》2005,97(3):468
Various cross-cultural researchers state that autonomy is not valued in Eastern cultures and, hence, is unlikely to predict optimal study functioning and well-being. In contrast, self-determination theory (SDT; R. M. Ryan & E. L. Deci, 2000) maintains that autonomous or volitional study motivation is universally important and should predict better learning and higher well-being, even among Chinese students. Two studies were conducted to shed light on this controversial issue. Findings from both studies indicated that autonomous study motivation positively predicts adaptive learning attitudes, academic success, and personal well-being, whereas controlled motivation was associated with higher drop-out rates, maladaptive learning attitudes, and ill-being. In addition, Study 2 revealed that parental autonomy support versus psychological control is related to more adaptive learning strategies and higher well-being and that these effects were mediated by students' relative autonomy for studying. The importance of defining autonomy as an intraindividual, phenomenological experience versus an interpersonal, culturally bounded value is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献