If you are using handful of search terms you can use the filter box for the particular field, or "Search all". To enable this mode - please click on the small arrow next to the filer name on the sidebar, then tick the option "Show text tools", mode "all" and "substring", as per image.



You could also use the Import option to look for multiple words from an external list.

Alternatively, if you are looking for hundreds of keywords, there is a more efficient way to do it in the DataManager space. You can use the Merge operation, to join the dataset with the lookup file, that contains all the search words, while the merge criteria is set to "contains".
(see the example here http://forums.visokio.com/discussion/comment/10460/#Comment_10460 )