Perhaps you should try some spelling variations:
"central a research program stress." » "central a research project stress.", "central a research program success.", "central a research program synthesis.", "central 2 research program stress.", "central la research program stress.", "central _ research program stress.", "central 1 research program stress."
"central a research programs stress." » "central a research projects stress.", "central a research programs series.", "central a research programs systems.", "central 2 research programs stress.", "central la research programs stress.", "central _ research programs stress.", "central 1 research programs stress."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("central a research program stress.") OR ("central a research programs stress."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"central a research program stress.\") OR (\"central a research programs stress.\"))*".
• Removing quotes may allow a broader search: (( central a research program stress. ) OR ( central a research programs stress. ))*.