Enclose a phrase with double quotation marks, e.g., "heart attack".
Heart attack, without double quotation marks, will be searched as heart AND attack.
Use an asterisk (*) to replace 0 or more characters in a word:
AND narrows a search by combining the main concepts.
For example, streaming and network will find documents that contain both terms.
OR broadens a search by including synonyms, acronyms and related keywords.
For example, aids or "acquired immune deficiency syndrome" or hiv or "human immunodeficiency virus" will find documents that contain any of the terms.
AND NOT excludes a term.
For example, apple and not fruit will find documents that contain the word apple but not the word fruit.
PRE/n specifies the proximity between two terms in an exact order.
For example, voice pre/3 ip will find documents in which voice appears before ip by no more than three words.
W/n specifies the proximity between two terms in any order.
For example, pain w/5 morphine means pain can appear before or after morphine by no more than five words.
Rules for Using Operators