Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
doan van » doan va, hoang van, luan van
hieu van » thien van, lieu va, hieu ve
thuoc ma » hoc ma, duoc ma
cua tre » cua te, cuu tre, cua triet
van cua » vang cua, ban cua, dan cua
ky lang » ky nang, ky dang, ky tang
lang ha » long ha
ma doan » ma dan, tap doan, va doanh
hieu va » lieu va, hieu qua
te cac » tu cac, ve cac, de cac
ha hoi » hoa hoi, ha noi, xa hoi
te cao » te bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te cac) OR (te cao)) ky lang ha hoi. ((hieu van) or (hieu va)) nam thuoc ma doan van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te cac) OR (te cao)) ky lang ha hoi. ((hieu van) OR (hieu va)) nam thuoc ma doan van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te cac) OR (te cao)) ky lang ha hoi. ((hieu van) or (hieu va)) nam thuoc ma doan van cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te cac) OR (te cao)) ky lang ha hoi. ((hieu van) or (hieu va)) nam thuoc ma doan van cua tre*.