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排序方式: 共有316条查询结果,搜索用时 15 毫秒
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This paper explores the vertical upward jumping of a planar biped. The jumping process is decomposed into the crouching phase, the thrust in the knees, the flight phase, the touchdown, and the straightening up movement of the biped. A mathematical model for this kind of jump of the biped is developed. Torques are applied in the hip and knee joints. The degree of underactuation of the mechanism is equal to one in the support phase and to three in the flight phase. The control algorithm is designed to ensure the jump of the biped. This algorithm is such that the center of mass of the mechanism is always placed on the same vertical line. The biped touches the ground in the same place where it starts from. The synthesis of the jumping process is supported by simulations which give consistent results with human data from existing biomechanical literature. Furthermore, the stick diagram of the jump derived from these simulation results seems natural for the human jumping. The problem of energy recovery is considered for the jumping of the biped by using springs in the hip and knee joints. The springs have an influence to minimize the mechanical energy consumed by the drives in the hip and knee joints. The springs in the knees help to increase the lifting of the bipedal mechanism. 相似文献
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Bahoumina Prince Hallil Hamida Lachaud Jean-Luc Rebière Dominique Dejous Corinne Abdelghani Aymen Frigui Kamel Bila Stephane Baillargeat Dominique Zhang Qing Coquet Phillipe Paragua Carlos Pichonat Emmanuelle Happy Henri 《Microsystem Technologies》2022,28(6):1365-1378
Microsystem Technologies - This study presents the results on the feasibility of a resonant planar chemical capacitive sensor in the microwave frequency range suitable for gas detection and... 相似文献
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Elena Lopez Adrien Leygue Emmanuelle Abisset-Chavanne Sebastien Comas-Cardona Christophe Aufrere Christophe Binetruy Francisco Chinesta 《International Journal of Material Forming》2017,10(3):317-328
The fundamental macroscopic material property needed to quantify the flow in a fibrous medium viewed as a porous medium is the permeability. Composite processing models require the permeability as input data to predict flow patterns and pressure fields. As permeability reflects both the magnitude and anisotropy of the fluid/fiber resistance, efficient numerical techniques are needed to solve linear and nonlinear homogenization problems online during the flow simulation. In a previous work the expressions of macroscopic permeability were derived in a double-scale porosity medium for both Newtonian and rheo-thinning resins. In the linear case only a microscopic calculation on a representative volume is required, implying as many microscopic calculations as representative microscopic volumes exist in the whole fibrous structure. In the non-linear case, and even when the porous microstructure can be described by a unique representative volume, microscopic calculation must be carried out many times because the microscale resin viscosity depends on the macroscopic velocity, which in turn depends on the permeability that results from a microscopic calculation. Thus, a nonlinear multi-scale problem results. In this paper an original and efficient offline-online procedure is proposed for the efficient solution of nonlinear flow problems in porous media. 相似文献
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Direct Observation of Localized Radial Oxygen Migration in Functioning Tantalum Oxide Memristors
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Flavien PilletAuthor Vitae Carmen RomeraAuthor Vitae Emmanuelle TrévisiolAuthor Vitae Sophie BellonAuthor VitaeMarie-Paule Teulade-FichouAuthor Vitae Jean-Marie FrançoisAuthor Vitae Geneviève PratvielAuthor Vitae Véronique Anton LeberreAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):304-309
Surface plasmon resonance imaging (SPRi) is a label free technology for biomolecular interaction, which gives access to binding kinetic parameters from real time acquisition. It offers the possibility to test in a single run a large number of interactions, allowing rapid identification of the most suitable compounds toward a given biological entity. Until now, this technique has proven to be relevant for interaction between relatively large molecules (protein, antibodies, DNA) but has not been challenged yet for the screening of small molecules that can be of interested in the field of drug discovery. As a proof a principle, we have used SPRi to screen for interaction of several small molecules, referred to as G4-ligands on G-quadruplex DNA. This technology allowed to easy discrimination of the binding properties of four G4-ligands on quadruplex DNA models. 相似文献
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We have identified and cloned the cDNAs encoding two odorant-binding proteins (OBPs) from the American palm weevil (APW) Rhynchophorus palmarum (Coleoptera, Curculionidae). Degenerate primers were designed from the N-terminal sequences and were used in polymerase chain reaction (PCR) in order to obtain full-length sequences in both males and females. In both sexes, two different cDNAs were obtained, encoding 123 and 115 amino acid-deduced sequences. Each sequence showed few amino acid differences between the sexes. The proteins were named RpalOBP2 and RpalOBP4 for male, RpalOBP2' and RpalOBP4' for female, with the types 2 and 4 presenting only 34% identities. These proteins shared high identity with previously described coleopteran OBPs. In native gels, RpalOBP2 clearly separated into two bands and RpalOBP4 into three bands, suggesting the presence of several conformational isomers. Thus, OBP diversity in this species may rely on both the presence of OBPs from different classes and the occurrence of isoforms for each OBP. 相似文献
10.
Tuomas Alapieti Emmanuelle Castagnoli Laura Salo Raimo Mikkola Pertti Pasanen Heidi Salonen 《Indoor air》2021,31(5):1563-1576
The emissions of volatile organic compounds (VOCs) from building materials may significantly contribute to indoor air pollution, and VOCs have been associated with odor annoyance and adverse health effects. Wood materials together with coatings are commonly used indoors for furniture and large surfaces such as walls, floors, and ceilings. This leads to high surface-to-volume ratios, and therefore, these materials may participate remarkably to the VOC levels of indoor environment. We studied emissions of VOCs and carbonyl compounds from pinewood (Pinus sylvestris) boards of 10% and 16% moisture contents (MC) with three paints using small-scale test chambers (27 L). The emissions from uncoated pinewood and paints (on a glass substrate) were tested as references. The 28-day experiment showed that the VOC emissions from uncoated pinewood were lower from sample with 16% MC. Painted pinewood samples showed lower emissions compared to paints on glass substrate. Additionally, paints on 16% MC pinewood exhibited lower emissions than on drier 10% MC wood. The emissions from painted pinewood samples were dominated by paint-based compounds, but the share of wood-based compounds increased over time. However, we noticed differences between the paints, and wood-based emissions were clearly higher with the most permeable paint. 相似文献