Search function in Lectora

Hello,

I use the search function to e.g. to search for "dummy" and "background". So far I haven't found a way to search for both words in a query at the same time. If I enter a search function separately for both words, hits are displayed. I've already searched using a comma or semicolon as a separator; but unfortunately it didn't lead to any result. Is there perhaps a solution for this? Thanks.

ekmud