Perhaps you should try some spelling variations:
hang hai » hoang hai, hang tai, thanh hai
te sach » toc sach
cao duc » cao suc, giao duc, tao duoc
hai cua » thai cua, dai cua, hoi cua
va hang » van hang, va nang, va lang
hieu ve » hieu va, hieu van
dao duc » giao duc, tao duoc
y nang » ky nang, ly nang, v nang
me hoi » le hoi
cua su » qua su

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 nang ((me hoi) or (ma hoa)). hieu ve ((cao duc) OR (dao duc)) va hang hai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((me hoi) OR (ma hoa)). hieu ve ((cao duc) OR (dao duc)) va hang hai cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((me hoi) or (ma hoa)). hieu ve ((cao duc) OR (dao duc)) va hang hai cua su".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((me hoi) or (ma hoa)). hieu ve ((cao duc) OR (dao duc)) va hang hai cua su*.