Perhaps you should try some spelling variations:
"human plants periodicals." » "human arts periodicals.", "human planning periodicals.", "human products periodicals.", "humans plants periodicals.", "human plant periodicals.", "human placenta 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."

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("human games periodicals.") or ((("human ages periodicals.") or ("human plants periodicals."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("human games periodicals.") OR ((("human ages periodicals.") OR ("human plants periodicals.")))).
• Removing quotes may allow a broader search: (( human games periodicals. ) or ((( human ages periodicals. ) or ( human plants periodicals. )))).
• Adding a wildcard symbol may retrieve word variants: (("human games periodicals.") or ((("human ages periodicals.") or ("human plants periodicals."))))*.