"Words or phrase" searches every field available in the record, including but not limited to all of the ones available in the list. This option is great for broader searches and getting an idea of all resources available on your chosen word. There is a catch to this search method, however; sometimes keyword searches can be overly broad. So if you are interested in researching various cultures and societies throughout the world, a search for a single term such as "culture" will yield many results, not all of which will be on topic.
Located at the top of the page, you will see how many results your particular search term retrieves. This is true of whether you use words or phrase, author, title, subject or any of the other search fields. You'll notice right away that the search for the word "culture" has produced 27 pages of results with a total of 526 titles to search through. This is because the system is searching the entirety of the record for instances of that single term. It is searching the information that is in the subject field, title field, author field and even fields that aren't specifically searchable such as various notes like the summary. As a result, you will get books that deal with culture or certain cultures, but you will also get results such as this:
The very first result is for the 2012 motion picture remake of Footloose. Why does Footloose show up in a search for culture?
You can also get results on cultivating bacteria in a petri dish or musical albums by the Culture Club. Despite these results, you will get resources dealing with other cultures, cultural time periods, "high culture," cultural movements, cultural regions, cultural strife, etc. While all of these may contain necessary information, 526 titles is more than anyone would really care to sift through with a deadline looming. Luckily, the online catalog contains tools built into the search to help you eliminate these off topic results.