Perhaps you should try some spelling variations:
"online classes research arguments" » "online classes research catchments", "online classes research students", "online classes research elements", "online class research arguments", "online cases research arguments", "online classes search arguments", "online courses research arguments"
"online sale research contents" » "online sale research content", "online sale research context", "online sale research concepts", "online scale research contents", "online sales research contents", "online shale research contents", "online self research contents", "online safety research contents"

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 classes research arguments") OR ("online sale research contents")).
• Removing quotes may allow a broader search: (( online classes research arguments ) or ( online sale research contents )).
• Adding a wildcard symbol may retrieve word variants: (("online classes research arguments") or ("online sale research contents"))*.