Perhaps you should try some spelling variations:
communication instrumentation » communication documentation, communication interpretation, ionization instrumentation
theorem diffusion » theory diffusion, thermo diffusion, theorem discussions
theory division » theory decision, theory revision, theorems division
bases linear » based linear, basics linear, basic linear

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

• Performing a fuzzy search may retrieve terms with similar spellings: communication instrumentation ((theory division) or (theorem diffusion)) bases linear~.
• If you are trying to use Boolean operators, they must be ALL CAPS: communication instrumentation ((theory division) OR (theorem diffusion)) bases linear.
• Adding a wildcard symbol may retrieve word variants: communication instrumentation ((theory division) or (theorem diffusion)) bases linear*.