To search for multiple words, separate each word with a comma. For example, entering pipeline, safety will return all documents containing the words pipeline or safety or both; or
use OR to return all documents that contain any of the words you specified. For example, entering pipeline OR safety will return all documents containing pipeline or safety or both.

All forms of a word you specified in the Search for field

You can search for all forms of a word. For example, entering pipe* will return pipe, pipes, pipeline, pipelines and so on.

Exact word or phrase you specified

You can search for an exact word or phrase by typing the words without punctuation. For example, entering pipeline safety will return all documents containing the phrase pipeline safety; or
by enclosing the word or phrase in quotation marks. For example, entering "pipeline safety" will return all documents containing the phrase "pipeline safety".

All the words you specified in the Search for field

Use AND to return all documents that contain all the words you specified. For example, entering pipeline AND safety would return all documents containing the words pipeline and safety.

All the words you specified in the Search for field on the same page

Use NEAR to return all documents that contain all the words you specified close to each other. For example, pipeline NEAR safety looks for both words on the same page.

The first word you specified in the Search for field but not the second word

Use AND NOT to return all documents that contain the first word you entered but not the second word. For example, entering pipeline AND NOT safety would return documents that only contained pipeline but not safety.