Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
thu sach » thuat sach, thuoc sach, thu hoach
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
hieu va » lieu va, hieu qua
lai cua » dai cua, hai cua, lai chau
duc van » duc va, duc tan, duc manh
tu sach » su sach, te sach, tu cach
lang xa » lang ha, dang xay, lang van
tu lang » cu lang, tu lanh, xu lang
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) OR (thu sach)) tu lang xa hoi. ((hieu van) or (hieu va)) pham duc van hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) tu lang xa hoi. ((hieu van) OR (hieu va)) pham duc van hanh lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) tu lang xa hoi. ((hieu van) or (hieu va)) pham duc van hanh lai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) tu lang xa hoi. ((hieu van) or (hieu va)) pham duc van hanh lai cua tre*.