To require that a word be included in your search, place a plus symbol (+) in front of it.
Important: there should be no space between the + symbol and your word, for example, +wildflowers.

To prevent a word from being included in your search results, preface it with a minus symbol (-).
As with required terms, there can be no space between your word and the - symbol.
Although it may seem unlikely that you'll ever have need to exclude a word from your search, there are instances where this feature can be very helpful. Imagine you are searching for Java (the programming language); prohibiting the word coffee from your search will greatly increase the relevancy of your results.