A multiple word search can include logical constructs such as "and", "or", and "not". A boolean "and" between words is assumed, meaning documents that contain all of the words will be found. If you wish to find all of the documents that have any one of the specified words, then include an "or" between the words.
To truncate a word, type an asterisk (*) at the end of the word. For example, searching for "tech*" will find documents that contain the words "technicial", "technology", and "technical", among others