Keywords include Digi-Key part numbers, manufacturer part numbers, manufacturer names or any other descriptive text related to the products for which you are searching. You may use full words, prefixes, suffixes, or even substrings.
Normally spaces separate keywords, so you do not need quotation marks. You only need to use quotation marks around a keyword when you want to embed spaces in it.
By default, the search operation will only return records that contain all of your keywords. The spaces separating keywords behave implicitly as logical AND operators. However, you may also explicitly use the logical operators ".and.", ".or.", and ".not." in your list of keywords. Or to save keystrokes, you may substitute "|" for ".or.", and "~" for ".not."