Perhaps you should try some spelling variations:
"a national research center" » "a operational research center" (Expand Search), "a educational research center" (Expand Search), "a international research center" (Expand Search), "a national research centre" (Expand Search), "a national research under" (Expand Search), "a national research register" (Expand Search), "_ national research center" (Expand Search)
"_ translational research career" » "_ transnational research career" (Expand Search), "_ translation research career" (Expand Search), "_ translating research career" (Expand Search), "_ translational research case" (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("a national research center") OR ("_ translational research career"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"a national research center\") OR (\"_ translational research career\"))".
• Removing quotes may allow a broader search: (( a national research center ) OR ( _ translational research career )).
• Adding a wildcard symbol may retrieve word variants: (("a national research center") OR ("_ translational research career"))*.