全文获取类型
收费全文 | 1225篇 |
免费 | 76篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 22篇 |
综合类 | 1篇 |
化学工业 | 337篇 |
金属工艺 | 13篇 |
机械仪表 | 18篇 |
建筑科学 | 37篇 |
矿业工程 | 1篇 |
能源动力 | 50篇 |
轻工业 | 217篇 |
水利工程 | 6篇 |
石油天然气 | 3篇 |
无线电 | 72篇 |
一般工业技术 | 209篇 |
冶金工业 | 63篇 |
原子能技术 | 14篇 |
自动化技术 | 240篇 |
出版年
2024年 | 2篇 |
2023年 | 22篇 |
2022年 | 80篇 |
2021年 | 91篇 |
2020年 | 44篇 |
2019年 | 44篇 |
2018年 | 39篇 |
2017年 | 40篇 |
2016年 | 51篇 |
2015年 | 45篇 |
2014年 | 48篇 |
2013年 | 82篇 |
2012年 | 86篇 |
2011年 | 99篇 |
2010年 | 78篇 |
2009年 | 69篇 |
2008年 | 67篇 |
2007年 | 58篇 |
2006年 | 52篇 |
2005年 | 24篇 |
2004年 | 22篇 |
2003年 | 22篇 |
2002年 | 21篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 21篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1303条查询结果,搜索用时 30 毫秒
101.
Given a set of H ∞ design specifications, the issue is to check whether there exists a controller, whose order is free, which satisfies these specifications. The classical solution, which is based on Youla parametrization and convex closed loop design, is not really satisfactory since it should use an infinite dimensional basis of filters, which cannot be done in practice. Let J* the minimal value of the design objective over such an infinite dimensional basis of filters. A Nevanlinna Pick interpolation method is proposed here to compute lower and upper bounds of J*, by solving the design problem on a finite set of frequencies. Finite-time convergence of the algorithm is proved. 相似文献
102.
José María Arroyo-Caro Tarik Chileh Diego López Alonso Federico García-Maroto 《Lipids》2013,48(7):663-674
Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT, EC 2.3.1.23) catalyzes acylation of lysophosphatidylcholine (lysoPtdCho) to produce phosphatidylcholine (PtdCho), the main phospholipid in cellular membranes. This reaction is a key component of the acyl-editing process, involving recycling of the fatty acids (FA) mainly at the sn-2 position of PtdCho. Growing evidences indicate that the LPCAT reaction controls the direct entry of newly synthesized FA into PtdCho and, at least in some plant species, it has an important impact on the synthesis and composition of triacylglycerols. Here we describe the molecular characterization of the single LPCAT gene found in the genome of Ricinus communis (RcLPCAT) that is homologous to LPCAT genes of the MBOAT family previously described in Arabidopsis and Brassica. RcLPCAT is ubiquitously expressed in all organs of the castor plant. Biochemical properties have been studied by heterologous expression of RcLPCAT in the ale1 yeast mutant, defective in lysophospholipid acyltransferase activity. RcLPCAT preferentially acylates lysoPtdCho against other lysophospholipids (lysoPL) and does not discriminates the acyl chain in the acceptor, displaying a strong activity with alkyl lysoPL. Regarding the acyl-CoA donor, RcLPCAT uses monounsaturated fatty acid thioesters, such as oleoyl-CoA (18:1-CoA), as preferred donors, while it has a low activity with saturated fatty acids and shows a poor utilization of ricinoleoyl-CoA (18:1-OH-CoA). These characteristics are discussed in terms of a possible role of RcLPCAT in regulating the entry of FA into PtdCho and the exclusion from the membranes of the hydroxylated FA. 相似文献
103.
Juliana Vinholes Clara Grosso Paula B. Andrade Angel Gil-Izquierdo Patrícia Valentão Paula Guedes de Pinho Federico Ferreres 《Food chemistry》2011
Spergularia rubra is distributed all over the world, being its infusion used as diuretic. In spite of its large use, the antidiabetic, anti-cholinesterase and antioxidant activities of this species have not been assessed and its chemical composition is scarcely known. In the work herein a hydromethanolic extract was studied. 相似文献
104.
Federico Peinado Virginia Francisco Raquel Hervás Pablo Gervás 《Minds and Machines》2010,20(4):565-588
Novelty is a key concept to understand creativity. Evaluating a piece of artwork or other creation in terms of novelty requires
comparisons to other works and considerations about the elements that have been reused in the creative process. Human beings
perform this analysis intuitively, but in order to simulate it using computers, the objects to be compared and the similarity
metrics to be used should be formalized and explicitly implemented. In this paper we present a study on relevant elements
for the assessment of novelty in computer-generated narratives. We focus on the domain of folk-tales, working with simple
plots and basic narrative elements: events, characters, props and scenarios. Based on the empirical results of this study
we propose a set of computational metrics for the automatic assessment of novelty. Although oriented to the implementation
of our own story generation system, the measurement methodology we propose can be easily generalized to other creative systems. 相似文献
105.
Marissa Vargas‐Ramirez Antonio Romero‐Serrano Rodolfo Morales Miguel Angeles‐Hernandez Federico Chavez‐Alcala Javier Castro‐Arellano 《国际钢铁研究》2001,72(5-6):173-181
A mathematical model earlier proposed has been improved to predict the kinetics of multicomponent reactions in the hot metal pretreatment through the injection of reactive fluxes. It is assumed that there are two reaction zones along the flux injection operation: a transitory reaction between the rising particles and the bulk metal, and the permanent reaction between the metal and the top slag. A criterion to estimate the fraction of solids which will react with molten iron in a three‐phase jet (gas‐solid‐liquid) was considered; this fraction of solids carries out the transitory reaction. The model also takes into account the thermodynamic changes produced in the metal and slag due to the chemical reactions. Calculated results of the model are in good agreement with experimental results for the desulfurization of hot metal through the injection of CaO‐SiO2‐CaF2‐FeO‐Na2O reagents at 1400 ‐ 1450 °C. Two kinds of hot metal were tested, one with a low carbon mass content of 3 % and the other with a high carbon mass content of 4.5 %. 相似文献
106.
Federico Aulenta Andrea Canosa Luigi De Roma Priscilla Reale Stefania Panero Simona Rossetti Mauro Majone 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(6):864-870
BACKGROUND: A bioelectrochemical process for trichloroethene (TCE) dechlorination was developed. In this new process, a solid‐state electrode polarized to ?450 mV versus the standard hydrogen electrode (SHE), in combination with a redox mediator (i.e., methyl viologen, MV) is employed as an electron donor for the microbial reductive dechlorination of TCE. In this study we compared the performance of the process with the redox mediator immobilized at the surface of electrodes or dissolved in the bulk liquid, using both a culture highly enriched in Desulfitobacterium spp., capable of dechlorinating TCE to cis‐dichloroethene (cis‐DCE), and a culture highly enriched in Dehalococcoides spp. capable of dechlorinating cis‐DCE to ethene. RESULTS: Short‐term potentiostatic (?450 mV versus SHE) experiments showed that TCE or cis‐DCE was dechlorinated both in the presence of soluble (500 µmol L?1) and immobilized MV. However, TCE or cis‐DCE dechlorination rates with MV‐modified electrodes were remarkably lower than with soluble MV. Both cultures produced significant amounts of H2 in the presence of electrically reduced, soluble MV, whereas no H2 was produced when the mediator was immobilized at the electrode surface, regardless of the potential applied to the electrode, in the range ?425 to ?500 mV versus SHE. CONCLUSIONS: The process, operated with modified electrodes, supports the microbial dechlorination of TCE to ethene. Immobilization not only allows retention of the mediator within the system, but also increases process efficiency by preventing bioelectrochemical H2 formation. On the other hand, strategies to increase dechlorination rates with modified electrodes need to be developed. Copyright © 2009 Society of Chemical Industry 相似文献
107.
108.
Federico Lorussi Enzo Pasquale Scilingo Mario Tesconi Alessandro Tognetti Danilo De Rossi 《IEEE transactions on information technology in biomedicine》2005,9(3):372-381
In this paper, we report on a new technology used to implement strain sensors to be integrated in usual garments. A particular conductive mixture based on commercial products is realized and directly spread over a piece of fabric, which shows, after the treatment, piezoresistive properties, i.e., a change in resistance when it is strained. This property is exploited to realize sensorized garments such as gloves, leotards, and seat covers capable of reconstructing and monitoring body shape, posture, and gesture. In general, this technology is a good candidate for adherent wearable systems with excellent mechanical coupling with body surface. Here, we mainly focused on a sensorized glove able to detect posture and movements of the fingers. It could be used in several fields of application. We report on experimental results of a sensorized glove used as movements recorder for rehabilitation therapies and medicine. Furthermore, we describe a dedicated methodology used to read the output sensors which allowed to avoid using metallic wires for the connections. The price to be paid for all these advantages is a nonlinear electric response of the fabric sensor and a too long settling time, that in principle, make these sensors not suitable for real-time applications. Here we propose a hardware and computational solution to overcome this limitation. 相似文献
109.
Federico Cismondi Abigail L. Horn André S. Fialho Susana M. Vieira Shane R. Reti João M.C. Sousa Stan Finkelstein 《Expert systems with applications》2012,39(16):12332-12339
In many binary medical classification problems, the cost of misclassifying one category is higher than the other, and in these applications it is desirable to employ a classifier with selective sensitivity or specificity. This work explores the utility of a fuzzy multi–criteria function for performance evaluation during knowledge–based medical classification and prediction. The method presented here uses fuzzy optimization to combine the sensitivity, specificity, and accuracy of classification as goals in a single objective function. This approach is used to assign flexible goals, which can be used to maximize the outcome in terms of each one of the goals. The proposed approach significantly increases the sensitivity and the specificity while maintaining or increasing accuracy. The versatility of the method is further exploited in a multi-model approach, using individual structures of multi-objective optimization of sensitivity and specificity separately, and then combining their outcomes through a decision-making module. Among various medical benefits derived from applying this technique, the divergent feature sets selected by high sensitivity and specificity models lend insight into factors more integrally connected to what causes risk of death for patients. 相似文献
110.
Michael Beetz Freek Stulp Piotr Esden-Tempski Andreas Fedrizzi Ulrich Klank Ingo Kresse Alexis Maldonado Federico Ruiz 《Autonomous Robots》2010,28(1):21-44
This article investigates methods for achieving more general manipulation capabilities for mobile manipulation platforms,
which produce legible behavior in human living environments. To achieve generality and legibility, we combine two control
mechanisms. First of all, experience- and observation-based learning of skills is applied to routine tasks, so that the repetitive and stereotypical character of everyday activity is exploited. Second, we use planning, reasoning,
and search for novel tasks which have no stereotypical solution. We apply these ideas to the learning and use of action-related places, to the model-based
visual recognition and localization of objects, and the learning and application of reaching strategies and motions from humans.
We demonstrate the integration of these mechanisms into a single low-level control system for autonomous manipulation platforms. 相似文献