Perhaps you should try some spelling variations:
s.asi_ research » basic research, asia research
central s.asi_ » central asia, central s.a
research firm » research from, research field, research final
firm surveys » firm survey
team series » stem series, nejm series, tilsm series
a research » 2 research
central a » central la, central _, central 1

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: (( central s.asi_ research team series. ) OR ( central a research firm surveys. ))~.
• Adding a wildcard symbol may retrieve word variants: (( central s.asi_ research team series. ) or ( central a research firm surveys. ))*.