Perhaps you should try some spelling variations:
"online lin research documents" » "online lin search document", "online lin research arguments", "online lin research comments", "online line research documents", "online link research documents", "online win research documents", "online li research documents", "online linux research documents"
"online chapter6 research students" » "online chapter research students", "online chapter1 research students", "online chapter5 research students", "online chapter6 research studies", "online chapter6 research instruments", "online chapter6 research studying", "online chapters research students", "online chapter9 research students"
"online chapter6 research study" » "online chapter research study", "online chapter1 research study", "online chapter5 research study", "online chapters research study", "online chapter9 research study"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("online lin research documents") OR ((("online chapter6 research students") OR ("online chapter6 research study"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"online lin research documents\") or (((\"online chapter6 research students\") OR (\"online chapter6 research study\"))))*".
• Removing quotes may allow a broader search: (( online lin research documents ) or ((( online chapter6 research students ) OR ( online chapter6 research study ))))*.