Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
hieu van » thien van, lieu va, hieu ve
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hac tu » hoc tu, tac tu, cac tu
tu van » tu va
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (thuat sach)) ty nang x hoi. ((hieu van) OR (hieu va)) hac tu van hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ty nang x hoi. ((hieu van) OR (hieu va)) hac tu van hanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuat sach)) ty nang x hoi. ((hieu van) OR (hieu va)) hac tu van hanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuat sach)) ty nang x hoi. ((hieu van) OR (hieu va)) hac tu van hanh dai cua tre*.