Perhaps you should try some spelling variations:
communication documentation » communication foundation, communication communication, communication conversation
documentation gas » documentation fast, documentation a, documentation g
gas dispersion » wave dispersion, _ dispersion
ray line » ray lines
ray anne » gray anne, gray annie, ray jeanne

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

• Performing a fuzzy search may retrieve terms with similar spellings: communication documentation gas dispersion ((ray line) OR (ray anne))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "communication documentation gas dispersion ((ray line) OR (ray anne))".
• Adding a wildcard symbol may retrieve word variants: communication documentation gas dispersion ((ray line) OR (ray anne))*.