Perhaps you should try some spelling variations:
"pressure research series" » "present research series", "pressure release series", "pressure research services", "pressure research studies", "pressure research summaries"
"resource research theories" » "resources research theories", "source research theories", "resource search theories", "resource research theory", "resource research themes", "resource research topics"
"residue research service" » "residues research service", "residual research service", "rescue research service", "residue search service", "residue research overview", "residue research section"
"tissue research series" » "issues research series", "disease research series", "tissue research services", "tissue research studies", "tissue research summaries"

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