Perhaps you should try some spelling variations:
van hoai » van thoai, van hoa, van hai
hoai duc » hoa duoc, hong duc, ho duc
thu nang » thi nang, thu hang, thu bang
vanh dai » van dai, vanh tai, lanh dao
hanh dai » hanh tai, hanh dao, thanh dat
duc manh » suc manh, duc anh, duc minh
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
te sach » toc sach
ma hoi » mai hoi, xa hoi, me hoi
cua tu » cua tuc, cua su, cua cu

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 thu nang ((ma hoi) OR (ma hoa)). hieu van hoai duc manh ((hanh dai) or (vanh dai)) cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thu nang ((ma hoi) OR (ma hoa)). hieu van hoai duc manh ((hanh dai) OR (vanh dai)) cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thu nang ((ma hoi) OR (ma hoa)). hieu van hoai duc manh ((hanh dai) or (vanh dai)) cua tu".
• Adding a wildcard symbol may retrieve word variants: te sach thu nang ((ma hoi) OR (ma hoa)). hieu van hoai duc manh ((hanh dai) or (vanh dai)) cua tu*.