Perhaps you should try some spelling variations:
thanh vi » hanh vi, thanh va, thanh ve
cua quoc » cua nuoc, cua thuoc
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, lai hoi, mai doi
dai hoi » dai hoc, dai hai, dai moi
hieu ve » hieu va, hieu van
xuc van » luc van, vuc van, xuc ban
duc van » duc va, duc tan, duc manh
y lang » o lang, _ lang, tay lang
ve cam » ve cham, ve cac, va cam
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y lang ((mai hoi) OR (dai hoi)). hieu ve cam ((xuc van) or (duc van)) thanh vi cua quoc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y lang ((mai hoi) OR (dai hoi)). hieu ve cam ((xuc van) OR (duc van)) thanh vi cua quoc.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y lang ((mai hoi) OR (dai hoi)). hieu ve cam ((xuc van) or (duc van)) thanh vi cua quoc".
• Adding a wildcard symbol may retrieve word variants: tu sach y lang ((mai hoi) OR (dai hoi)). hieu ve cam ((xuc van) or (duc van)) thanh vi cua quoc*.