Perhaps you should try some spelling variations:
among farmers » salmon farmers
patients 1.8 » patients 10.1, patients 10.5, patients 10.6
1.8 among » 1.5 among, 19 among, 1 among
yan yang » yang yang, yao yang, dan yang
wai yan » wang yan, wei yang
fan de » aan de, jan de, can de
van de » van den

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: wai yan yang ((fan de) OR (((van de) OR (van der)))) patients 1.8 among farmers ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wai yan yang ((fan de) or (((van de) OR (van der)))) patients 1.8 among farmers ;~".
• Adding a wildcard symbol may retrieve word variants: wai yan yang ((fan de) or (((van de) OR (van der)))) patients 1.8 among farmers ;*.