Hi Farah,
You can use smart search filter for that. You can use this kind of syntax in where condition for specific field:
+animals:"dogs"
where 'animals' is name of the field in kenico page type (must be checked as searchable) and 'Dogs' is value that you need. If you want to search over all fields, you can use something like this:
+_content:"dogs"
This will do search over all fields and return items (pages) that contains 'dogs' keyword, not only in 'animals' field.