Perhaps you should try some spelling variations:
"tissues engineering" » "tissue engineering", "tissue bioengineering", "tissue engineered"
"_ tissueengineering" » "tissue engineering"
"tissue engeneering" » "tissue engineering", "tissue bioengineering", "tissue engineered"

Try widening your search to All Fields.

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: (("tissues engineering") OR ((("tissue engeneering") OR ("_ tissueengineering")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"tissues engineering\") or (((\"tissue engeneering\") OR (\"_ tissueengineering\"))))".
• Removing quotes may allow a broader search: (( tissues engineering ) or ((( tissue engeneering ) OR ( _ tissueengineering )))).
• Adding a wildcard symbol may retrieve word variants: (("tissues engineering") or ((("tissue engeneering") OR ("_ tissueengineering"))))*.