Perhaps you should try some spelling variations:
"an introduction _ computer programmingrs" » "an introduction _ computer programming" (Expand search), "an introduction _ computers programming" (Expand search), "an introduction _ computer programmers" (Expand search), "an introduction _ computer programamingrs" (Expand search)
"advanced python python computer program" » "advanced method python computer program" (Expand search), "advanced path python computer program" (Expand search), "advanced symphony python computer program" (Expand search), "advanced pythons python computer program" (Expand search), "advanced piton python computer program" (Expand search), "advanced pitons python computer program" (Expand search), "advanced python python computer programa" (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: (("an introduction _ computer programmingrs") OR ("advanced python python computer program"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"an introduction _ computer programmingrs\") OR (\"advanced python python computer program\"))".
• Removing quotes may allow a broader search: (( an introduction _ computer programmingrs ) OR ( advanced python python computer program )).
• Adding a wildcard symbol may retrieve word variants: (("an introduction _ computer programmingrs") OR ("advanced python python computer program"))*.