Perhaps you should try some spelling variations:
"uk national study" » "uk sectional study" (Expand Search), "sub national study" (Expand Search), "u.s national study" (Expand Search), "use national study" (Expand Search)
"uk national soul" » "uk national oil" (Expand Search), "uk national roll" (Expand Search), "uk national youth" (Expand Search), "sub national soul" (Expand Search), "u.s national soul" (Expand Search), "use national soul" (Expand Search)
"dso national soul" » "dso national oil" (Expand Search), "dso national roll" (Expand Search), "dso national youth" (Expand Search), "lao national soul" (Expand Search), "use national soul" (Expand Search), "datu national soul" (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: (((("uk national soul") OR ("uk national study"))) OR ("dso national soul"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"uk national soul\") OR (\"uk national study\"))) OR (\"dso national soul\"))".
• Removing quotes may allow a broader search: (((( uk national soul ) OR ( uk national study ))) OR ( dso national soul )).
• Adding a wildcard symbol may retrieve word variants: (((("uk national soul") OR ("uk national study"))) OR ("dso national soul"))*.