Perhaps you should try some spelling variations:
"tissue research theories" » "tissue research theory", "tissue research themes", "tissue research topics", "issues research theories", "pressure research theories", "disease research theories"
"residue research series" » "residues research series", "residual research series", "rescue research series", "residue research services", "residue research studies", "residue research service"

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: (("residue research series") OR ("tissue research theories")).
• Removing quotes may allow a broader search: (( residue research series ) or ( tissue research theories )).
• Adding a wildcard symbol may retrieve word variants: (("residue research series") or ("tissue research theories"))*.