全文获取类型
收费全文 | 279篇 |
免费 | 22篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 103篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 4篇 |
轻工业 | 61篇 |
水利工程 | 2篇 |
无线电 | 15篇 |
一般工业技术 | 32篇 |
冶金工业 | 21篇 |
原子能技术 | 1篇 |
自动化技术 | 50篇 |
出版年
2023年 | 5篇 |
2022年 | 29篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 7篇 |
2017年 | 13篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 14篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 17篇 |
2008年 | 17篇 |
2007年 | 17篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
排序方式: 共有301条查询结果,搜索用时 15 毫秒
201.
Luca Valgimigli Enrico Sanjust Nicoletta Curreli Augusto Rinaldi Gian F. Pedulli Antonio Rescigno 《Journal of the American Oil Chemists' Society》2001,78(12):1245-1248
A photometric method is proposed that allows the determination of phenolase activity in olive fruits, olive pastes, and virgin
olive oil. The method can also be used to quantify partially purified phenolase from olives, and is based on the coupling
between 4-methyl-o-benzoquinone, the reaction product of phenolase toward its substrate 4-methylcatechol, and the aromatic amine 4-amino-N,N-diethylaniline. The deep-blue adduct arising from this reaction has been characterized by means of nuclear magnetic resonance
and mass spectrometric techniques and identified as 4-(4′-diethylaminophenylimino)-2-hydroxy-5-methyl-cyclohexa-2,5-dienone.
This compound shows an absorption band, centered (in dichloromethane) at 617 nm, with an ε of 11,080 M−1cm−1. The main advantage of the proposed method resides in the high absorption coefficient of the adduct and its ultraviolet/visible
absorption pattern, with a λmax in a spectral region void of significant interferences by the pigments that ultimately will probably be present in the extracts
to be tested by this proposed method. The method has proven to be sensitive, specific, and reliable.
This paper is dedicated to the memory of Professor Francesco Corongiu, Dean of the Faculty of Sciences, University of Cagliari,
prematurely deceased one year ago. 相似文献
202.
R Betz B Boden R Triolo M Mesgarzadeh E Gardner R Fife 《Canadian Metallurgical Quarterly》1996,34(3):127-136
Nineteen adolescent subjects with complete spinal cord injuries resulting in paraplegia or tetraplegia participated in a functional electrical stimulation (FES) program consisting of computerized, controlled exercise and/or weight bearing. The effects of stimulated exercise and standing/walking on the lower extremity joints were prospectively studied. Plain radiographs and MRIs were obtained prior to and following completion of the exercise and standing and walking stages. In addition, the joints of five subjects were studied with synovial biopsies, arthroscopy, and the analysis of serum and synovial fluid for a 550 000 dalton cartilage matrix glycoprotein (CMGP). Pre-exercise joint abnormalities secondary to the spinal cord injury improved following the stimulation program. None of the subjects developed Charcot joint changes. Upon standing with FES, one subject with poor hip coverage prior to participation developed hip subluxation which required surgical repair. No other detrimental clinical effects occurred in the lower extremity joints of subjects participating in an FES program over a 1-year period. 相似文献
203.
Antonietta Alonge Nicoletta Calzolari Piek Vossen Laura Bloksma Irene Castellon Maria Antonia Marti Wim Peters 《Computers and the Humanities》1998,32(2-3):91-115
In this paper the linguistic design of the database under construction within the EuroWordNet project is described. This is mainly structured along the same lines as the Princeton WordNet, although some changes have been made to the WordNet overall design due to both theoretical and practical reasons. The most important reasons for such changes are the multilinguality of the EuroWordNet database and the fact that it is intended to be used in Language Engineering applications. Thus, i) some relations have been added to those identified in WordNet; ii) some labels have been identified which can be added to the relations in order to make their implications more explicit and precise; iii) some relations, already present in the WordNet design, have been modified in order to specify their role more clearly. 相似文献
204.
205.
206.
Conductances at 25°C were measured in the following systems: Potassium chlorate in water-methanol and in water-ethylene carbonate mixtures, and sodium-chlorate in some water-methanol mixtures. Both salts are poorly associated in water but addition of small amounts of methanol or of ethylene carbonate markedly increases and decreases respectively the association. These results, not explained on the basis of a continuum model, can be rationalized considering a specific solvation in connection with the structure of the solvent mixtures. 相似文献
207.
Natural gas‐based transportation in the USA: economic evaluation and policy implications based on MARKAL modeling 下载免费PDF全文
The recent divergence in domestic energy costs between oil and natural gas drives an investigation of the potential for further demand‐side utilization of natural gas in the USA. An economic assessment of the US transportation sector was conducted with a focus on the penetration of technologies that use natural gas as a fuel. Bottom‐up modeling of the US energy system using the market allocation framework enabled estimation of the optimal technology mix in both the light‐duty and heavy‐duty vehicle segments, over a 40‐year time horizon, under various scenarios of technical learning rates and natural gas prices. A modified functional form of Moore's law was developed and anchored to municipal transit bus data, to represent technical learning with regard to natural gas vehicle costs. Modeling results suggest that the present levels of natural gas vehicle penetration are suboptimal and a number of market failures were identified, which are most likely to propagate under‐adoption into the foreseeable future. Some policy guidelines, aimed at the federal level, were outlined as potential responses to the market failures discussed herein. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
208.
Petri nets for modelling metabolic pathways: a survey 总被引:1,自引:1,他引:0
In the last 15 years, several research efforts have been directed towards the representation and the analysis of metabolic
pathways by using Petri nets. The goal of this paper is twofold. First, we discuss how the knowledge about metabolic pathways
can be represented with Petri nets. We point out the main problems that arise in the construction of a Petri net model of
a metabolic pathway and we outline some solutions proposed in the literature. Second, we present a comprehensive review of
recent research on this topic, in order to assess the maturity of the field and the availability of a methodology for modelling
a metabolic pathway by a corresponding Petri net. 相似文献
209.
Peter Berggren Björn JE Johansson Nicoletta Baroutsi 《Theoretical Issues in Ergonomics Science》2017,18(2):128-146
Objective, easy to use, and easy to comprehend assessment methods for measuring shared understanding in teams are hard to find. This paper describes an experiment where a measure called Shared Priorities, which is based on ranking of self-generated strategic items, is assessed. Trained teams were compared to non-trained teams in a dynamic problem-solving task. The maturity of the participating teams was also assessed using a content analysis measure. The Shared Priorities measure was used alongside other well-documented measures of team awareness based on self-rating. Results show that the Shared Priorities measure correlates with task performance and could also distinguish between trained and non-trained teams. However, the Shared Priorities measure did not correlate with the other team measures (cf. CARS – Crew Awareness Rating Scale – and DATMA – Distributed Assessment of Team Mutual Awareness), suggesting that it captures a different quality of teamwork than the self-rating measures. Further, the Shared Priorities measure was found to be easily administered. 相似文献
210.
Yoshihiko Hayashi Bora Savas Monica Monachini Claudia Soria Nicoletta Calzolari 《Language Resources and Evaluation》2012,46(2):253-264
This paper demonstrates that Wordnet-LMF, a version of ISO LMF, allows us to effectively design and implement Web services for accessing WordNet-type semantic lexicons that conform to the REST Web service architecture. The implemented prototype service currently provides access to native wordnets as well as to a bilingual concept dictionary. This paper thus describes slight revisions that were made to the Wordnet-LMF specifications to model and accommodate a non-wordnet-native bilingual concept dictionary. 相似文献