Sites with both the words cats and dogs would not be among the results. Almost every search engine can use Boolean operators, but each search engine has different rules for constructing searches. Read the help screens unique to that search engine for advice. Search terms should be separated by spaces. Use quotes to limit your search to sites which contain all of the words together in a phrase.
Most search engines recognize quotation marks in the same way.
Your search will be greatly focussed by the addition of quotes. Use capital letters for proper names. This can greatly increase the relevancy of your search results. Check your spelling. Try different words that mean the same thing.