Searching for specific text within a cell

Im looking for the function that looks in a cell and tells me if a certain word is contained within that cell. There are other words in the cells as well but I just want to denote in a new column the cells that contain the word dog etc. I've tried enclosing what I'm looking for in $, *, ~ in an IF statement, but it doesn't seem to work. Any ideas?

Thanks.

This will return TRUE if "dog" appears in A1

=ISNUMBER(SEARCH("dog",A1))

SEARCH is not case-sensitive so this returns TRUE if A1 contains "dog" or "DOG", if you want it to be case-sensitive use FIND instead of SEARCH

note: this formula returns TRUE if cell contains "hotdog" or "doggone". If you don't want that, assuming cell contains just words with spaces between

=ISNUMBER(SEARCH(" dog "," "&A1&" "))