Perhaps you should try some spelling variations:
values research » issues research, changes research
central values » central value, central valley, control values
asi2 research » asia research, basic research, 2 research
research nejm » research new, research need, research needs
central asi2 » central asia, central asian, central asia's
from surveys » from survey, firm surveys, force surveys

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( central asi2 research nejm series. ) or ( central values research from surveys. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( central asi2 research nejm series. ) OR ( central values research from surveys. )).
• Adding a wildcard symbol may retrieve word variants: (( central asi2 research nejm series. ) or ( central values research from surveys. ))*.