PATTERN MATCHING QUERIES
It is also called "Fuzzy Query".
You can enter "ungrammatical sentences", "incomplete sentence fragments", "disjoint phrases", "nonsense words".
The search engine get the collection of keywords.
Required keyword: Mark with "+" before the keyword.
Prohibited keyword: Mark with "-" before the keyword.
A Boolean Query is a query that consists keywords but with logical operators (AND, OR, NOT).
X AND Y - will return URLs that contain both X and Y.
X OR Y - will return URLs that contain either X or Y.
X AND NOT Y - will return URLs that contain X and do not contain Y.
Symbol: AND-&, OR-I, NOT-I, NEAR-~.