Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
hieu ve » hieu va, hieu van
vai cua » dai cua, hai cua, lai cua
tuc van » thuc van, truc van, tuc va
cam tuc » cam xuc, cam tu, nam thuc
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
_ lang » o lang, _ land
y lang » o lang, tay lang, yen lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ((y lang) or (_ lang)) xa hoi. hieu ve cam tuc van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ((y lang) OR (_ lang)) xa hoi. hieu ve cam tuc van hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ((y lang) or (_ lang)) xa hoi. hieu ve cam tuc van hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ((y lang) or (_ lang)) xa hoi. hieu ve cam tuc van hanh vai cua tre*.