Perhaps you should try some spelling variations:
"duplex explained illustrated" » "duplex explain illustrate", "duplex england illustrated", "duplex ireland illustrated", "builder explained illustrated", "amply explained illustrated", "build explained illustrated"
"duplex plants illustrated" » "duplex parts illustrated", "duplex plainly illustrated", "duplex islands illustrated", "duplex plates illustrated", "duplex placenta illustrated"

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: (("duplex plants illustrated") OR ("duplex explained illustrated")).
• Removing quotes may allow a broader search: (( duplex plants illustrated ) or ( duplex explained illustrated )).
• Adding a wildcard symbol may retrieve word variants: (("duplex plants illustrated") or ("duplex explained illustrated"))*.