Google improves Search every year by training its algorithms to understand the language and environment to help you find exactly what you are looking for online.
In one post on The Keyword, Google describes in detail how in some searches the results in Search are not as expected. In the very few cases where Google does not return the correct results, you will see the message: "There do not appear to be any results for your search" (It looks like there aren't any great matches for your search).
This message will be accompanied by some tips to help you further improve your search. The idea is that by providing more (and clearer) information, Google will be able to turn its failures into successes. It will even provide alternative search terms to try.
Google will obviously continue to provide results and it is up to you whether or not you use them. The company simply admits in advance that it may not deliver what you are looking for.
Google actually wants to point out that it is already using a number of methods to avoid this. For example, if you type something incorrectly, Google Search will detect the misspellings and provide results for the words and phrases that it thinks you intended to type.
To be fair, Google is usually great when it comes to helping you find what you are looking for on the web. This means that you are unlikely to ever see this message. However, in the strange case that Google can not offer some results, do not be surprised.