Perhaps you should try some spelling variations:
"human gamers periodicals." » "human games periodicals.", "human cameras periodicals.", "human farmers periodicals.", "human gametes periodicals.", "human cancers periodicals.", "human traders periodicals.", "human gazers periodicals.", "human geners periodicals.", "human gaitrs periodicals."
"human sites periodicals." » "human states periodicals.", "human fishes periodicals.", "human wastes periodicals.", "human bites periodicals.", "human side periodicals.", "human stem periodicals."
"human game periodicals." » "human games periodicals.", "human flame periodicals.", "human care periodicals.", "human gaze periodicals.", "human gene periodicals.", "human gait 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 sites periodicals.") or ((("human gamers periodicals.") OR ("human game periodicals."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("human sites periodicals.") OR ((("human gamers periodicals.") OR ("human game periodicals."))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"human sites periodicals.\") or (((\"human gamers periodicals.\") OR (\"human game periodicals.\"))))*".
• Removing quotes may allow a broader search: (( human sites periodicals. ) or ((( human gamers periodicals. ) OR ( human game periodicals. ))))*.