Arabic Search Engines Improvement: A New Approach using Search Key Expansion Derived from Arabic Synonyms Structure. - Hayder K. Al Ameed; Shaikha O. Al Ketbi; Amna A. Al Kaabi; Khadija S. Al Shebli; Naila F. Al Shamsi; Noura H. Al Nuaimi; Shaikha S. Al Muhairi (AICCSA, 2006)