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排序方式: 共有1915条查询结果,搜索用时 15 毫秒
61.
Alexandre Benoit Laurent Bonnaud Alice Caplier Phillipe Ngo Lionel Lawson Daniela G. Trevisan Vjekoslav Levacic Céline Mancas Guillaume Chanel 《Personal and Ubiquitous Computing》2009,13(1):33-41
This paper presents a driver simulator, which takes into account the information about the user’s state of mind (level of
attention, fatigue state, stress state). The user’s state of mind analysis is based on video data and biological signals.
Facial movements such as eyes blinking, yawning, head rotations, etc., are detected on video data: they are used in order
to evaluate the fatigue and the attention level of the driver. The user’s electrocardiogram and galvanic skin response are
recorded and analyzed in order to evaluate the stress level of the driver. A driver simulator software is modified so that
the system is able to appropriately react to these critical situations of fatigue and stress: some audio and visual messages
are sent to the driver, wheel vibrations are generated and the driver is supposed to react to the alert messages. A multi-threaded
system is proposed to support multi-messages sent by the different modalities. Strategies for data fusion and fission are
also provided. Some of these components are integrated within the first prototype of OpenInterface: the multimodal similar
platform. 相似文献
62.
Alexandre Boulgakov Thomas Gibson-Robinson A. W. Roscoe 《Formal Aspects of Computing》2016,28(3):381-407
We present and compare several algorithms for computing the maximal strong bisimulation, the maximal divergence-respecting delay bisimulation, and the maximal divergence-respecting weak bisimulation of a generalised labelled transition system. These bisimulation relations preserve CSP semantics, as well as the operational semantics of programs in other languages with operational semantics described by such GLTSs and relying only on observational equivalence. They can therefore be used to combat the space explosion problem faced in explicit model checking for such languages. We concentrate on algorithms which work efficiently when implemented rather than on ones which have low asymptotic growth. 相似文献
63.
Cantrell KJ Yabusaki SB Engelhard MH Mitroshkov AV Thornton EC 《Environmental science & technology》2003,37(10):2192-2199
Previous studies have demonstrated that gas-phase H2S can immobilize certain redox-sensitive contaminants (e.g., Cr, U, Tc) in vadose zone environments. A key issue for effective and efficient delivery of H2S in these environments is the reactivity of the gas with indigenous iron oxides. To elucidate the factors that control the transport of H2S in the vadose zone, laboratory column experiments were conducted to identify reaction mechanisms and measure rates of H2S oxidation by iron oxide-coated sands using several carrier gas compositions (N2, air, and O2) and flow rates. Most experiments were conducted using ferrihydrite-coated sand. Additional studies were conducted with goethite- and hematite-coated sand and a natural sediment. Selective extractions were conducted at the end of each column experiment to determine the mass balance of the reaction products. XPS was used to confirm the presence of the reaction products. For column experiments in which ferrihydrite-coated sand was the substrate and N2 was the carrier gas, the major H2S oxidation products were FeS and elemental sulfur (mostly S8(0), represented as S(0) for simplicity) at ratios that were consistent with the stoichiometry of the postulated reactions. When air or O2 were used as the carrier gas, S(0) became the dominant reaction product along with FeS2 and smaller amounts of FeS, sulfate, and thiosulfate. A mathematical model of reactive transport was used to test the hypothesis that S(0) forming on the iron oxide surfaces reduces access of H2S to the reactive surface. Several conceptual models were assessed in the context of the postulated reactions with the final model based on a linear surface poisoning model and fitted reaction rates. These results indicate that carrier gas selection is a critical consideration with significant tradeoffs for remediation objectives. 相似文献
64.
Mariana S. Silveira Cláudia P. M. L. Fontes Alexandre A. Guilherme Fabiano A. N. Fernandes Sueli Rodrigues 《Food and Bioprocess Technology》2012,5(3):947-953
The aim of the present work was to investigate the use of cashew apple juice as a low cost substrate for Lactobacillus casei B-442 cultivation and lactic acid production. Ammonium sulfate was employed as the only exogenous nitrogen source. The effect
of cashew apple juice reducing sugars and ammonium sulfate concentration and the fermentation pH and temperature on biomass
formation, lactic acid production, and productivity were evaluated. The highest productivity (2.36 g/L.h) was obtained applying
50 g/L of reducing sugar from the cashew apple juice supplemented with 6 g/L of ammonium sulfate. The process yield was about
95% when fermentation was carried out at 37 °C with pH controlled at pH 6.5 using NaOH (120 g/L). 相似文献
65.
Adriano Gomes Alexandre Mota Augusto Sampaio Felipe Ferri Edson Watanabe 《International Journal on Software Tools for Technology Transfer (STTT)》2012,14(6):673-702
The aerospace industry still uses fault trees to perform reliability analysis. This is because fault-tree modeling and analysis (FTA) seems easier to practical engineers when compared with Markov models, even though FTA provides a weaker form of analysis. In this paper, we propose an automatic strategy for generating Markov-based models and corresponding analysis formulations, according to ARP 4761, directly from Simulink diagrams annotated with failure information. The generated Markov-based models are expressed in the formal language PRISM, and the analysis is carried out by the PRISM model checker. The strategy is compositional and based on a comprehensive set of translation rules from Simulink to PRISM. We briefly address soundness and completeness of the rules and, to illustrate the application of the strategy, we apply it to a classical avionics case study: an actuator control system. 相似文献
66.
Johnny Guzman Alexandre Madureira Marcus Sarkis Shawn Walker 《Journal of scientific computing》2018,77(3):1736-1761
We derive error estimates for the piecewise linear finite element approximation of the Laplace–Beltrami operator on a bounded, orientable, \(C^3\), surface without boundary on general shape regular meshes. As an application, we consider a problem where the domain is split into two regions: one which has relatively high curvature and one that has low curvature. Using a graded mesh we prove error estimates that do not depend on the curvature on the high curvature region. Numerical experiments are provided. 相似文献
67.
Alexandre Caboussat Roland Glowinski Dimitrios Gourzoulidis 《Journal of scientific computing》2018,77(1):53-78
In this article, we address the numerical solution of the Dirichlet problem for the three-dimensional elliptic Monge–Ampère equation using a least-squares/relaxation approach. The relaxation algorithm allows the decoupling of the differential operators from the nonlinearities. Dedicated numerical solvers are derived for the efficient solution of the local optimization problems with cubicly nonlinear equality constraints. The approximation relies on mixed low order finite element methods with regularization techniques. The results of numerical experiments show the convergence of our relaxation method to a convex classical solution if such a solution exists; otherwise they show convergence to a generalized solution in a least-squares sense. These results show also the robustness of our methodology and its ability at handling curved boundaries and non-convex domains. 相似文献
68.
This paper investigates the combustion characteristics of 12 wood species natural to Brazil. A mass loss cone calorimeter was used to obtain the properties associated with (i) heat release rate (HRR), peak HRR, and total heat released; (ii) total mass loss and mass loss rate; (iii) average effective heat of combustion; and (iv) time to ignition, time of pyrolysis and temperature of ignition. The samples used in this work were as follows: (i) prepared in accordance to ISO 5660‐1:2002; (ii) oven dried; (iii) irradiated with a constant heat flux of 50 kW/m2; and (iv) exhibit wood fiber orientation in a plane orthogonal to the flux incidence. Finally, the paper explores the possibility of linking the obtained combustion properties with the density and classes of selected wood species. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
69.
Marcos R. Guilherme Adriano V. Reis Alexandre T. Paulino André R. Fajardo Edvani C. Muniz Elias B. Tambourgi 《应用聚合物科学杂志》2007,105(5):2903-2909
This contribution describes the absorption percentage of Pb2+ and Cu2+ from water by a superabsorbent hydrogel matrix (SH) made from an anionic polysaccharide copolymerized with acrylic acid (AAc) and acrylamide (AAm). Metal‐absorption tests, upon sequential pH variation, indicated that the SH has pH‐sensitivity for the absorption of both metals from solution, attributed to the functional ionic groups (? COOH) present in the AAc and arabic gum (AG) segments. At the pH 5.0, the SH exhibited good absorption capacity: 73.10% for Pb2+, 81.99% for Cu2+ in water and 63.64% for Pb2+, and 76.67% for Cu2+ in saline water with 0.1 mol kg?1 ionic strength. A replicated 22 full factorial design with a central point was built to evaluate the maximum absorption capacity of the metals into the SH. It was found that both the interaction and main effects of the pH and the initial concentration of metal solution on absorption percentage of the metals were statistically significant. Surface response plots indicated that the absorption capacity of both metals into the SH may be appreciably improved by using the solutions with lower initial concentration of metal and with higher pH values. Metal‐absorption results demonstrated that the SH is a convenient material for absorption of Pb2+ and Cu2+ from pure aqueous and saline aqueous environments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
70.
Graded evolution of anisotropic microstructure during sintering from crystal-oriented powder compact
Shoko Baba Alexandre Maître Nicolas Pradeilles Guy Antou Nobuo Saito Satoshi Tanaka 《International Journal of Applied Ceramic Technology》2020,17(2):677-684
Anisotropic sintering, including shrinkage and grain growth, was examined for c-axis-oriented (Sr,Ca)2NaNb5O15 (SCNN) ceramics, which were prepared by colloidal processing under a magnetic field. In the c-axis-oriented SCNN powder compact, shrinkage and grain growth along the c-axis were higher than those along the a-axis. The anisotropic microstructural development was clearly associated with anisotropic sintering shrinkage. X-ray diffraction, scanning electron microscopy, and energy back scattering diffraction showed that the grain growth of oriented particles by including random grains contribute to the development of the oriented microstructure. Finally, the highly crystal-oriented SCNN ceramics with a densified microstructure were obtained through anisotropic sintering. These results clearly showed the potential to develop a well-defined anisotropic microstructure during sintering by designing and controlling the particle packing structure in a powder compact. 相似文献