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41.
MICHAEL A. PITTARELLI 《国际通用系统杂志》2013,42(1-2):165-177
Abstract Databases may exhibit many forms of incompleteness. This paper explores methods for overcoming incompleteness in the form of missing tuples. Specifically, algorithms are investigated for replacing a relation that is known to be incomplete with a superset. Of particular interest are algorithms that make available at any time a current approximation and with the property that the approximate solution improves monotonically with computing time. Although this paper concentrates on rule matching in rule-based systems, application of these and similar methods to problems of knowledge discovery in incomplete databases is also discussed. 相似文献
42.
ROSS D. KING JONATHAN D. HIRST MICHAEL J. E. STERNBERG 《Applied Artificial Intelligence》2013,27(2):213-233
A common step in pharmaceutical development is the formation of a quantitative structure-activity relationship *(QSAR) to model an exploratory series of compounds. A QSAR generalizes how the structure (shape) of a compound relates to its biological activity. A comparative study was carried out of six artificial intelligence and traditional algorithms for modeling QSAR's: GOLEM, CART, and MS from symbolic machine learning; back-propagation from neural networks; and linear regression and nearest-neighbor from traditional statistics. Two test case problems were studied: the inhibition of Escherichia coli dihydrofolate reductase (DHFR) by pyrimidines, and the inhibition of ratlmouse tumor DHFR by triazines. It was found that there was no significant statistical difference between the methods in terms of their ability to rank unseen compounds by activity. However, symbolic machine learning methods, in particular relational ones, were found to generate rules that provided insight into the stereochemistry of compound receptor interactions. 相似文献
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A new concept for using a ferroelectric field effect transistor in a memory configuration is presented without the requirement of a negative voltage or an erase operation. The transistor is designed so that the accumulation sets in at a lower gate source voltage making it possible to reverse the polarization without applying a negative pulse to the gate. 相似文献
45.
The paper discusses the design of an Alpine Snow Cover Analysis System (ASCAS) for monitoring snow cover variations in the Alps. It is shown how data such as snow cover data derived from satellite, climate, hydrologic, and topographic data, are programmed into the system. Possible techniques for analysing snow cover variations and results are presented. Furthermore, the integration of image processing and GIS techniques with applied models on a microcomputer-based system is described. 相似文献
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SIEUWERT VAN OTTERLOO WIEBE VAN DER MICHAEL WOOLDRIDGE 《Applied Artificial Intelligence》2013,27(9-10):937-952
We are interested in applying model checking techniques to the verification of communication protocols that require safe communication. Typically, in such scenarios, one desires to demonstrate that one party can reliably communicate information to another party without a third party being able to determine this information. Our approach involves using the modal logic of knowledge, which has only relatively recently been studied in the context of security protocols. We demonstrate our approach by means of a detailed case study: the Russian cards problem. This is an example of a security protocol with nontrivial requirements on the knowledge of the agents involved. Using the Russian cards problem as an example, it is shown how the satisfaction of properties involving knowledge can be verified in a standard model checker, which in our case is SPIN. 相似文献
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CHARALAMPOS PROESTOS MARIA KAPSOKEFALOU MICHAEL KOMAITIS 《Journal of food quality》2008,31(3):402-414
Aromatic plants of Greek origin, Origanum dictamnus (dictamus), Eucalyptus globulus (eucalyptus), Origanum vulgare L. (oregano), Mellisa officinalis L. (balm mint) and Sideritis cretica (mountain tea) were examined for the content of phenolic substances. Reversed phase high performance liquid chromatography was used for the analysis of the plant extracts. Gas chromatography–mass spectrometry method was also used for identification of phenolic compounds after silylation. The most abundant phenolic acids were gallic acid (1.5–2.6 mg 100 g − 1 dry sample), ferulic acid (0.34–6.9 mg 100 g − 1 dry sample) and caffeic acid (1.0–13.8 mg 100 g − 1 dry sample). ( + )-Catechin and ( − )-epicatechin were the main flavonoids identified in oregano and mountain tea. Quercetin was detected only in eucalyptus and mountain tea.
Plant-derived polyphenols receive considerable interest because of their potential antioxidant and antimicrobial properties. Undoubtedly, it is very important not only to determine those properties but also to determine each and every phenol in aromatic plants both qualitatively and quantitatively. A number of analytical methods have been proposed for the separation and determination of these compounds. Most of these protocols are based on a high performance liquid chromatography technique with ultraviolet spectrophotometry. Gas chromatography–mass spectrometry after silylation of the phenolic compounds is used in this research together with the aforementioned technique as an alternative and more sensitive method to detect and understand the compositional profile of the extracts as well as the structure and functional relationship of the components in the extracts, based on MS spectra. 相似文献
PRACTICAL APPLICATIONS
Plant-derived polyphenols receive considerable interest because of their potential antioxidant and antimicrobial properties. Undoubtedly, it is very important not only to determine those properties but also to determine each and every phenol in aromatic plants both qualitatively and quantitatively. A number of analytical methods have been proposed for the separation and determination of these compounds. Most of these protocols are based on a high performance liquid chromatography technique with ultraviolet spectrophotometry. Gas chromatography–mass spectrometry after silylation of the phenolic compounds is used in this research together with the aforementioned technique as an alternative and more sensitive method to detect and understand the compositional profile of the extracts as well as the structure and functional relationship of the components in the extracts, based on MS spectra. 相似文献