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31.
32.
Karina Fullenkamp Macarena Montané Gustavo Cáceres Gerardo Araya-Letelier 《国际可持续能源杂志》2019,38(6):561-582
In order to improve the thermal efficiency of building thermal energy storage (TES) systems, the feasibility of using encapsulated phase change materials (EPCMs) as heat storage media is analysed in this work. Specifically, the finite element method is used to perform thermal behaviour analyses of several EPCMs. These analyses include technical and economic assessments in order to identify the best combination of PCM and shell material, using as main parameters: thermal energy storage, heat transfer rate, materials cost, among others. The results show that EPCMs composed by Na2SO4·6H2O as PCM and covered by stainless steel highlight as TES materials. 相似文献
33.
Gerardo Espinosa-Velázquez Ana Mayela Ramos-de-la-Peña Julio Montanez Juan Carlos Contreras-Esquivel 《Food science and biotechnology》2018,27(2):411-415
Functional food has been highly demanded lately because of its benefits in counteracting diseases. Fucoidan and agave fructan are ingredients that enhance the growth of beneficial bacteria in the gut (prebiotics). This mixture has great potential to develop innovative products but it has never been explored before. Because of fucoidan is more expensive than agave fructan, the innovative proposed mixture is vulnerable to adulteration. This research was aimed to assess the accuracy of Fourier transform infrared spectroscopy with attenuated total reflectance (ATR–FTIR) coupled with chemometrics to identify and predict concentration of both polysaccharides in powder mixtures (0–100%). Absorption bands at 1240–1255 and 836–840 cm?1 were attributed to fucoidan and a strong peak at ~ 936 cm?1 confirmed the fructan presence. Peak areas were best fitted into linear models (\({\text{R}}_{\text{adj}}^{2}\) ≥ 0.92, RMSE ≤ 3.54%). This achievement may be useful to certificate ingredients contained in fucoidan–fructan mixtures, preventing adulteration. 相似文献
34.
Antioxidant activity, phenolic compounds and anthocyanins content of eighteen strains of Mexican maize 总被引:3,自引:0,他引:3
Free-radical scavenging, reducing activity and some phytochemical content (total phenolic, anthocyanin and ferulic acid) of eighteen Mexican maize phenotypes were determined. Total phenolic contents ranged from 215.8 to 3400.1 mg gallic acid/100 g of whole grain flour and total anthocyanins ranged from 1.54 to 850.9 mg cyanidin-glucoside equivalents/100 g of whole grain flour. Most of the phenolics in grain were in the bound form (ca. 85%), while anthocyanins were the major free phenolic compounds. Among the different samples, bound phenolic extracts of corn appeared to have greater anti-radical and reducing activities than free phenolic extracts from the same grain samples when tested at a normalized phenolic concentration. The phenotypes Veracruz 42 and AREQ516540TL exhibited the greatest activities and these purple-colored strains were most enriched in anthocyanins. Extracts from a red-colored phenotype Pinto were also among the most effective at exhibiting anti-radical activities. Differences in free-radical scavenging and reducing activities appeared to be dependent on the unique profile of anthocyanins and other phenolics in each phenotype. 相似文献
35.
Julian Szekely Ph.D. John Busch Ph.D. Gerardo Trapaga Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1996,48(12):43-47
Recent developments in modeling can eliminate much experimental laboratory work and can provide quick answers in a more cost-effective manner. This article presents a brief outline of technical cost modeling, a combination of physical modeling and cost modeling, which may be used to the mutual benefit of both the managerial decision makers and the R&D community within the materials processing field. 相似文献
36.
Jesus Alvarez Jose Alvarez-Ramirez Gerardo Espinosa-Perez Alexander Schaum 《Chemical engineering science》2011,(23):6280
Traditionally, stabilization of chemical reacting systems has been achieved with linear P or PD compensation schemes. Practical and numerical results have showed that classical linear compensation can yield acceptable performance. On the other hand, recent years have witnessed the emergence of systematic feedback control strategies based on energy and port-interconnected systems. These approaches exploit the physical structure of the chemical reactor to construct compensation schemes with physical appealing. The aim of this work is to show that traditional PD compensation for CSTRs can be interpreted in terms of mechanical system analogies. In the line of energy shaping plus damping injection for robotic systems, it is shown that proportional feedback is a type of potential energy shaping to accommodate a unique equilibrium point. On the other hand, derivative control acts as a damping injector for the energy balance within the chemical reactor. The stability proof uses a novel approach to convert the temperature dynamics into a second-order systems where the mechanical analogies become more evident. In this way, the stability analysis can be performed with singular perturbation methods with a Lyapunov function for the energy balance derived from a “potential plus kinetics” energy construction. 相似文献
37.
Sharona Khier Sandra Tolchinsky Gerardo Z. Lederkremer Boaz Shaanan 《Israel journal of chemistry》1994,34(2):177-184
A model for the carbohydrate recognition domain (CRD) and combining site of the human asialoglycoprotein (ASGP) receptor has been computed on the basis of the close sequence homology with the mannose-binding lectin (MBP), whose three-dimensional structure in complex with a ligand has been determined by crystallographic methods (Weis, W.I.; Drickamer, K.; Hendrickson, W.A. Nature 1992, 360: 127). Within the limitations of modeling methods, the model is compatible with data on ligand binding of the family C-type lectins, of which the MBP and the ASGP receptor are members. The model derived can serve as a guide for designing site-directed mutagenesis experiments in order to further elucidate the origins of specificity of the ASGP receptor toward galactose. In particular, the model focuses attention on the possible role of position 207 (MBP sequence numbering) in promoting galactose binding. 相似文献
38.
Multi-objective optimisation problems have seen a large impulse in the last decades. Many new techniques for solving distinct variants of multi-objective problems have been proposed. Production scheduling, as with other operations management fields, is no different. The flowshop problem is among the most widely studied scheduling settings. Recently, the Iterated Greedy methodology for solving the single-objective version of the flowshop problem has produced state-of-the-art results. This paper proposes a new algorithm based on Iterated Greedy technique for solving the multi-objective permutation flowshop problem. This algorithm is characterised by an effective initialisation of the population, management of the Pareto front, and a specially tailored local search, among other things. The proposed multi-objective Iterated Greedy method is shown to outperform other recent approaches in comprehensive computational and statistical tests that comprise a large number of instances with objectives involving makespan, tardiness and flowtime. Lastly, we use a novel graphical tool to compare the performances of stochastic Pareto fronts based on Empirical Attainment Functions. 相似文献
39.
Hiroshi Nishiura Gerardo Chowell Hans Heesterbeek Jacco Wallinga 《Journal of the Royal Society Interface》2010,7(43):297-307
The reporting interval of infectious diseases is often determined as a time unit in the calendar regardless of the epidemiological characteristics of the disease. No guidelines have been proposed to choose the reporting interval of infectious diseases. The present study aims at translating coarsely reported epidemic data into the reproduction number and clarifying the ideal reporting interval to offer detailed insights into the time course of an epidemic. We briefly revisit the dispersibility ratio, i.e. ratio of cases in successive reporting intervals, proposed by Clare Oswald Stallybrass, detecting technical flaws in the historical studies. We derive a corrected expression for this quantity and propose simple algorithms to estimate the effective reproduction number as a function of time, adjusting the reporting interval to the generation time of a disease and demonstrating a clear relationship among the generation-time distribution, reporting interval and growth rate of an epidemic. Our exercise suggests that an ideal reporting interval is the mean generation time, so that the ratio of cases in successive intervals can yield the reproduction number. When it is impractical to report observations every mean generation time, we also present an alternative method that enables us to obtain straightforward estimates of the reproduction number for any reporting interval that suits the practical purpose of infection control. 相似文献
40.