Perhaps you should try some spelling variations:
lam quoc » lam duoc, nam quoc, lam thuoc
quoc lan » quoc ban, nuoc luan, quoc quan
hieu van » hieu va, thien van, lieu va
benh va » benh dai, benh tai
benh ve » benh vien, benh viem
te sach » toc sach
van lam » van nam
cua tre » cua te, cuu tre, cua triet
y lang » o lang, tay lang, yen lang
_ lang » o lang, _ land

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((y lang) or (_ lang)) xa hoi. hieu van lam quoc lan ((benh ve) OR (benh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y lang) OR (_ lang)) xa hoi. hieu van lam quoc lan ((benh ve) OR (benh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y lang) or (_ lang)) xa hoi. hieu van lam quoc lan ((benh ve) OR (benh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((y lang) or (_ lang)) xa hoi. hieu van lam quoc lan ((benh ve) OR (benh va)) cua tre*.