Perhaps you should try some spelling variations:
"human sources periodicals." » "human resources periodicals.", "human countries periodicals.", "human sciences periodicals.", "human forces periodicals.", "human resource periodicals."
"human games periodicals." » "human gases periodicals.", "human homes periodicals.", "human genomes periodicals.", "human gamers periodicals.", "human game periodicals.", "human gametes periodicals."
"human ages periodicals." » "human agents periodicals.", "human bees periodicals.", "human changes periodicals.", "human age periodicals.", "human images periodicals."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("human sources periodicals.") or ((("human games periodicals.") OR ("human ages periodicals."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("human sources periodicals.") OR ((("human games periodicals.") OR ("human ages periodicals.")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"human sources periodicals.\") or (((\"human games periodicals.\") OR (\"human ages periodicals.\"))))".
• Removing quotes may allow a broader search: (( human sources periodicals. ) or ((( human games periodicals. ) OR ( human ages periodicals. )))).
• Adding a wildcard symbol may retrieve word variants: (("human sources periodicals.") or ((("human games periodicals.") OR ("human ages periodicals."))))*.