"whitespace regular expression"

Hello everybody,

I want to search words from documents. I use the operator Filter Tokens by content with regular expression. If I want to search more than one word I use word1|word2|...|wordn. Now my question is how can I search an expression where there is a whitespace? For example "Research and Development|Word2|Word3 etc. ". Is there any wildcard for whitespaces?

Thanks for your help