will return records where either the words 'cancer' or 'cancers' are present, plus the words 'cervical' or 'cervix', but not the phrase 'squamous cell carcinoma' or 'SCC'.
here the word 'chronic' must come somewhere before either the work 'leukemia' or 'leukaemia'.
this searches for the phrase 'kidney cancer' in the title as well as either the word 'trial' or 'trials' in description.
this searches for items where the word 'heart' exists in all of the headline, description and tags fields.