Perhaps you should try some spelling variations:
american scientists » american societies
medical scientists » biomedical scientists, physical scientists, medical sciences
robert walsh » robert walser, robert walt, robert walsers
robert welch » robert weech, robert wrench, robert wells
robert watt » robert watson, robert white

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: ((((robert walsh) OR (robert welch))) OR (robert watt)) (((medical scientists) OR (american scientists))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((robert walsh) or (robert welch))) or (robert watt)) (((medical scientists) OR (american scientists)))".
• Adding a wildcard symbol may retrieve word variants: ((((robert walsh) or (robert welch))) or (robert watt)) (((medical scientists) OR (american scientists)))*.