Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
hanh tai » thanh tai, hang tai, han tai
sach thu » sach thue, sach thieu, sach tham
van hanh » van thanh, ban hanh, van anh
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
hieu va » lieu va, hieu qua
sach tu » cach tu, sach ty, sach uu
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet

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 tu) OR (sach thu)) lang xa hoi. ((hieu van) or (hieu va)) pham duc van hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sach thu)) lang xa hoi. ((hieu van) OR (hieu va)) pham duc van hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach tu) OR (sach thu)) lang xa hoi. ((hieu van) or (hieu va)) pham duc van hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) OR (sach thu)) lang xa hoi. ((hieu van) or (hieu va)) pham duc van hanh tai cua tre*.