Perhaps you should try some spelling variations:
patients risk » patient risk, patients links, patients si
wang wang » wang liang, wang yan, wang yong
wang yang » wang yan, wang liang, wang yanling
jun cost » run cost, can cost
how slum » how slow, how sun
eu cost » au costa, der cost, end cost
how sub » how sun, flow sub

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: wang wang yang ((jun cost) OR (eu cost)) patients risk ((how slum) OR (how sub)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang wang yang ((jun cost) or (eu cost)) patients risk ((how slum) OR (how sub)) ;~".
• Adding a wildcard symbol may retrieve word variants: wang wang yang ((jun cost) or (eu cost)) patients risk ((how slum) OR (how sub)) ;*.