Perhaps you should try some spelling variations:
"health evidence network synthesis report" » "health evidence network systems report", "health science network synthesis report", "health guidance network synthesis report", "health dence network synthesis report"
"head impedance network synthesis report" » "head impedance network systems report", "head impedances network synthesis report", "end impedance network synthesis report", "board impedance network synthesis report"
"load impedance network synthesis report" » "load impedance network systems report", "ac impedance network synthesis report", "load imbalance network synthesis report"
health devices » health services, health service, health advice
health device » health service, health services

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: (((("health evidence network synthesis report") OR ("((health device) or (health devices)) network synthesis report"))) OR ((("head impedance network synthesis report") OR ("load impedance network synthesis report"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"health evidence network synthesis report\") or (\"((health device) or (health devices)) network synthesis report\"))) or (((\"head impedance network synthesis report\") OR (\"load impedance network synthesis report\"))))*".
• Removing quotes may allow a broader search: (((( health evidence network synthesis report ) or ( ((health device) or (health devices)) network synthesis report ))) or ((( head impedance network synthesis report ) OR ( load impedance network synthesis report ))))*.