Perhaps you should try some spelling variations:
hoc dung » hoc ung, hoc dan, tac dung
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
dao lai » dao lam, dao bai, dao hai
lai cua » dai cua, hai cua, lai chau
y lang » o lang, _ lang, tay lang
ha hoi » hoa hoi, ha noi, va hoi
va hoc » van hoc
va dao » ca dao
cua te » cua tu

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 ((ha hoi) or (xa hoi)). hieu va hoc dung va dao lai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y lang ((ha hoi) OR (xa hoi)). hieu va hoc dung va dao lai cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach y lang ((ha hoi) or (xa hoi)). hieu va hoc dung va dao lai cua te*.