Use the /n connector to find documents in which the first word appears within "n" words of the second one.
For example, the following search finds documents where the word "vicious" occurs within 3 words of "dog".
vicious /3 dog
Specifying the value of "n"
When choosing the value of n, these guidelines may prove useful:
Using Multiple /n Connectors
Multiple /n connectors are processed from the smallest to the largest.