unless you "force" a full phrase match, even documents with an exact match may not rise to the top of a result list

SearchDay - Using Search Engines to Fill in the Blank - 10 December 2002
Rather than agonizing over formulating the perfect query, take advantage of the power of search engines to easily "fill in the blank" for the answer to many types of questions.

All of the major search engines do reasonably well at phrase matching, where they attempt to find an exact match for all the words in your query in the order you enter them.

Most engines automatically attempt to do limited phrase matching on a multi-word query. However, unless you "force" a full phrase match, even documents with an exact match may not rise to the top of a result list if there are stronger matches based on the search engine's other relevance measures.
SearchDay - Using Search Engines to Fill in the Blank - 10 December 2002