On the other hand, by typing Injection , the search will only result in Injection . By typing in wells AND injection , the search will only return documents that contain both wells and injection . By typing in wells NOT injection , the search will return documents with the word wells that do not include the word injection . Add OR between words that must appear in result documents. By typing in wells OR injection , the search will return documents with the word wells and documents that include the word injection .
Parentheses determine how AND s and OR s are treated.
Words within parentheses are considered a unit and first in the search hierarchy.