للبحوث والأوراق العلمية والمراجع ..
1_http://education.iseek.com/iseek/home.page
2_ http://www.refseek.com/
3_http://m.wolframalpha.com/
4_http://academic.research.microsoft.com/
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6_http://www.siris.si.edu/
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11_http://www.sciseek.com/
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14 _ http://link.springer.com/
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https://scholar.google.com.eg/
