Multiple words are searched together as one phrase.
Example : world health organization
Wildcards
Words may be right-hand truncated using an asterisk ('*') in place of other characters.
The '*' wildcard may also be embedded in a search string. You may use '?' to replace a single character anywhere within a word.
Examples : environment* polic*, wom?n
Boolean Operators
Use "and" or "or" to specify multiple words in any field, any order. Use "and not" to exclude words.
Example : stocks and bonds
Example : (alaska or canada) and (adventure and not vacation)
Field Limits
A field limit causes the system to search only the specified field for the specified word(s).
Grouping
Word search results are usually grouped by relevance to bring the most likely titles to the top of the list.
Each group represents a similar level of relevance and results are sorted within the group by date or title.
To get an ungrouped result set, use boolean operators to form a complex query.
Most relevant titles 
Highly relevant titles 
Very relevant titles<