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排序方式: 共有525条查询结果,搜索用时 15 毫秒
71.
María?Elena?LópezEmail author Luis?Miguel?Bergasa Rafael?Barea María?Soledad?Escudero 《Autonomous Robots》2005,19(1):67-87
Assistant robots have received special attention from the research community in the last years. One of the main applications of these robots is to perform care tasks in indoor environments such as houses, nursing homes or hospitals, and therefore they need to be able to navigate robustly for long periods of time. This paper focuses on the navigation system of SIRA, a robotic assistant for elderly and/or blind people based on a Partially Observable Markov Decision Process (POMDP) to global localize the robot and to direct its goal-oriented actions. The main novel feature of our approach is that it combines sonar and visual information in a natural way to produce state transitions and observations in the framework of Markov Decision Processes. Besides this multisensorial fusion, a two-level layered planning architecture that combines several planning objectives (such as guiding to a goal room and reducing locational uncertainty) improves the robustness of the navigation system, as its shown in our experiments with SIRA navigating corridors. 相似文献
72.
Impurity depth profiles were obtained by differential sheet resistivity and Hall coefficient measurements on Si(100) implanted with indium to doses of 1013 and 1014 ions cm-2 at an energy of 190 keV.After recovery of the implant damage the samples were diffused in an inert atmosphere at temperatures ranging from 1000 to 1200 °C.The data show that the carrier concentration is nearly independent of the implanted dose, while the indium diffusivity in silicon is higher for the samples implanted at 1014 ions cm-2. The solid solubility of indium in silicon is around 1017 cm-3. The hole mobility is about half that of boron-doped silicon and, in the range considered, the main contribution to the resistivity is from ionized impurity scattering.A model is proposed to account for the peculiar behaviour observed in indium-implanted silicon. 相似文献
73.
74.
F Sanz M Soledad Cuétara A del Palacio CK Campbell L Johnson P Urruzunu M Pía Roiz 《Canadian Metallurgical Quarterly》1993,11(9):490-493
BACKGROUND: F. solani fungemia is unusual. Patients at risk are immunosuppressed, have underlying malignancy or severe debilitating diseases. METHODS: We report two cases of F. solani fungemia in two non neutropenic patients who had been treated with wide-spectrum antibiotics an/or systemic corticosteroids, parenteral nutrition and intravenous lines. Bactec NR-860 (Becton-Dickinson) system was used, and growth was detected in aerobic conditions (between 3-7 days of incubation). RESULTS: Removal of the catheters with or without i.v. amphotericin B were used successfully. CONCLUSION: The spectrum of Fusarium sp. fungemia is discussed. Current available antifungal therapy is also reviewed. 相似文献
75.
A supramolecular solvent made up of reverse micelles of decanoic acid was proposed for the simple and rapid extraction of Sudan I, II, III and IV from chilli-containing foodstuffs. The procedure involved the extraction of minute quantities (0.5–1 g) of homogenised food sample with an aqueous solution containing 10% THF and 200 mg of decanoic acid, conditions under which the supramolecular solvent (around 330 μL) formed in situ and instantaneously. The overall sample treatment took about 30 min and several samples could be simultaneously treated using conventional lab equipment. No clean-up or solvent evaporation were required before determination of Sudan dyes by liquid chromatography and photometric detection. Extractions were independent of salt addition (up to 1 M), the temperature (up to 60 °C) and the pH (below 4) rendering the method robust. The detection limits of the method were 4.2, 2.7, 6.5 and 7.4 μg kg−1 for Sudan I, II, III and IV, respectively. Recoveries obtained by applying this approach to the analysis of six chilli-containing sauces fortified with Sudan dyes at the μg kg−1 level were in the interval 86–108% with relative standard deviations between 2% and 7%. 相似文献
76.
Mezadri T Fernández-Pachón MS Villaño D García-Parrilla MC Troncoso AM 《Archivos latinoamericanos de nutrición》2006,56(2):101-109
The acerola (Malpighia emarginata Sessé y Moci?o ex DC) is a wild plant grown in zones of tropical and subtropical climate. Acerola is origin from South of Mexico, Central America and Septentrional area of South America. Its scientific name was adopted in 1986 by the International Council of Vegetable Genetic Resources. Malpighia emarginata has a subglobulose drupa fruit with three seeds which account between the 19 - 25% of the total weight. The diameter and weight of the fruit varies between 1 - 4 cm and 2 - 15 g, respectively. The fruit shows green color when it is developing, which changes to yellow and red tones when it is mature. Each plant produces annually 20 - 30 kg of fruits. This fruit contents macro and micronutrients: proteins (0.21-0.80 g/100 g), fats (0.23-0.80 g/100 g), carbohydrates (3.6-7.80 g/100 g), mineral salts (iron 0.24, calcium 11.7, phosphorus 17.1 mg/100 g) and vitamins (thiamine 0.02, riboflavine 0.07, piridoxine 8.7 mg/100 g). Its high content in vitamin C (695 a 4827 mg/100 g) is remarkable, therefore acerola has an increasing economic value by its great consume during last years. Acerola also presents carotenoids and bioflavonoids which provide important nutritive value and its potential use as antioxidant. Brazil has a climate and soil appropriate for the culture of acerola, thus this country is the main mundial productor. Acerola is commercialised as juices, jams, ices, gelatins, sweets or liquors. Bibliographical data have been mainly supplied by Electronic Resources of the University of Seville and the University do Vale do Itajaí (Santa Catarina, Brazil). 相似文献
77.
Javier Tuya María Jos Surez‐Cabal Claudio de la Riva 《Software Testing, Verification and Reliability》2010,20(3):237-288
In the field of database applications a considerable part of the business logic is implemented using a semi‐declarative language: the Structured Query Language (SQL). Because of the different semantics of SQL compared with other procedural languages, the conventional coverage criteria for testing are not directly applicable. This paper presents a criterion specifically tailored for SQL queries (SQLFpc). It is based on Masking Modified Condition Decision Coverage (MCDC) or Full Predicate Coverage and takes into account a wide range of the syntax and semantics of SQL, including selection, joining, grouping, aggregations, subqueries, case expressions and null values. The criterion assesses the coverage of the test data in relation to the query that is executed and it is expressed as a set of rules that are automatically generated and efficiently evaluated against a test database. The use of the criterion is illustrated in a case study, which includes complex queries. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
78.
79.
María Jesús Cejudo-Bastante Isidro Hermosín-Gutiérrez María Soledad Pérez-Coello 《Food chemistry》2011
In this paper, the effects of micro-oxygenation before malolactic fermentation and oak chip treatments on Petit Verdot red wines have been evaluated. Our attention was focused on the colour characteristics, the phenolic compounds related to the colour of red wine, the volatile compounds, and the sensory characteristics of the wines. The micro-oxygenation treatment promoted the stabilisation of red wine colour by increasing the formation of colour-related phenolic compounds (higher concentrations of pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts). Red wine aroma quality was improved with the addition of oak chips (eugenol and 4-vinyl-guaiacol concentration increased). Micro-oxygenation treatment resulted in higher scores for the plum/currant and spicy attributes, as well as the appearance of tobacco and nutty notes which were absent in the non-treated wines. Nevertheless, the typical oak chip aromas (vanilla and woody) were observed to a lesser extent in wines obtained by micro-oxygenation. 相似文献
80.
Luis Carlos Mndez‐Gonzlez Luis Alberto Rodríguez‐Picn Delia Julieta Valles‐Rosales Alejandro Alvarado Iniesta Abel Eduardo Quezada Carren 《Quality and Reliability Engineering International》2019,35(4):1219-1230
Today in reliability analysis, the most used distribution to describe the behavior of devices is the Weibull distribution. Nonetheless, the Weibull distribution does not provide an excellent fit to lifetime datasets that exhibit bathtub shaped or upside‐down bathtub shaped (unimodal) failure rates, which are often encountered in the performance of products such as electronic devices (ED). In this paper, a reliability model based on the exponentiated Weibull distribution and the inverse power law model is proposed, this new model provides a better approach to model the performance and fit of the lifetimes of electronic devices. A case study based on the lifetime of a surface‐mounted electrolytic capacitor is presented in this paper. Besides, it was found that the estimation of the proposed model differs from the Weibull classical model and that affects the mean time to failure (MTTF) of the capacitor under analysis. 相似文献