Perhaps you should try some spelling variations:
health sciences » earth sciences
head impedances » load impedance, end impedance, good impedances
systems report » systems support, systems recent, systems transport
health disease » heart disease
network system » networked systems
head impedance » load impedance, end impedance, board impedance
system report » system reform, system support, system reforms
health dense » healthy sense, health device, health degree

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 science) OR (health sciences)) network systems report ) OR ( ((health dense) OR (health disease)) network system report ))) OR ( ((head impedance) OR (head impedances)) network synthesis report )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( ((health science) OR (health sciences)) network systems report ) or ( ((health dense) or (health disease)) network system report ))) or ( ((head impedance) or (head impedances)) network synthesis report ))".
• Adding a wildcard symbol may retrieve word variants: (((( ((health science) OR (health sciences)) network systems report ) or ( ((health dense) or (health disease)) network system report ))) or ( ((head impedance) or (head impedances)) network synthesis report ))*.