Perhaps you should try some spelling variations:
"advanced modulation _ computer program" » "advanced calculation _ computer program" (Expand search), "advanced oxidation _ computer program" (Expand search)
"advanced simulation using computer program" » "advanced calculation using computer program" (Expand search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("advanced modulation _ computer program") OR ("advanced simulation using computer program"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"advanced modulation _ computer program\") OR (\"advanced simulation using computer program\"))".
• Removing quotes may allow a broader search: (( advanced modulation _ computer program ) OR ( advanced simulation using computer program )).
• Adding a wildcard symbol may retrieve word variants: (("advanced modulation _ computer program") OR ("advanced simulation using computer program"))*.