"and" between words is assumed; that is, documents will be retrieved that have all the specified words. If you wish to find all the documents that have any word, use "or" between your search words.
To exclude a word, use not. For example, population not growth will find all documents that contain population but not growth.
To truncate a word, use an asterisk (*) at the end. For example, the search "sustain*" would retrieve documents that have the words "sustainable", "sustainability", "sustaining", etc.
