Perhaps you should try some spelling variations:
improv\ » improve\ (Expand Search), improved\ (Expand Search)
improveeed\ » improveeeed\ (Expand Search), improvedeeed\ (Expand Search), improved\ (Expand Search), improveed\ (Expand Search), improveded\ (Expand Search)
improvedeee » improveedeee (Expand Search), improvededeee (Expand Search)
improveedd » improveeedd (Expand Search), improvedeedd (Expand Search), improved (Expand Search), improvedd (Expand Search), improveddd (Expand Search)
improvee » improveee (Expand Search), improvedee (Expand Search), improve (Expand Search), improved (Expand Search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\ theatre (((improv\ OR improveeed\) OR improvedeee ) OR improveedd )) OR (\ theatre improvee ))~".
• Adding a wildcard symbol may retrieve word variants: ((\ theatre (((improv\ OR improveeed\) OR improvedeee ) OR improveedd )) OR (\ theatre improvee ))*.