Perhaps you should try some spelling variations:
physical scientists » political scientists, physical sciences, physical societies
medical scientists » biomedical scientists, american scientists, medical sciences
robert walser » robert walker, robert warren, robert watson
robert walsh » robert walt, robert welch, robert walsers
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 walser))) OR (robert watt)) (((medical scientists) OR (physical scientists))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((robert walsh) OR (robert walser))) or (robert watt)) (((medical scientists) or (physical scientists)))".
• Adding a wildcard symbol may retrieve word variants: ((((robert walsh) OR (robert walser))) or (robert watt)) (((medical scientists) or (physical scientists)))*.