Perhaps you should try some spelling variations:
thien bang » khien bang, thien ban, thien dang
thue bang » thu bang, thuat bang, thuoc bang
hieu van » hieu va, thien van, lieu va
cua tre » cuu tre, cua triet, dua tren
dan vai » dan va, dan tai, dan vat
tu sach » thu sach, su sach, te sach
van cam » van nam, van lam, van cau
cam tu » cam thu, nam tu, dam tu
va dan » ca dan, va dao, va dau
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 ((thue bang) OR (thien bang)) xa hoi. hieu van cam tu va dan vai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((thue bang) OR (thien bang)) xa hoi. hieu van cam tu va dan vai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((thue bang) OR (thien bang)) xa hoi. hieu van cam tu va dan vai ((cua tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((thue bang) OR (thien bang)) xa hoi. hieu van cam tu va dan vai ((cua tre) or (cua te))*.