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

• Performing a fuzzy search may retrieve terms with similar spellings: (("(radio OR ratio) wave propagation") OR ("(radio OR ratio) have propagation"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"(radio OR ratio) wave propagation\") OR (\"(radio OR ratio) have propagation\"))".
• Removing quotes may allow a broader search: (( (radio OR ratio) wave propagation ) OR ( (radio OR ratio) have propagation )).
• Adding a wildcard symbol may retrieve word variants: (("(radio OR ratio) wave propagation") OR ("(radio OR ratio) have propagation"))*.