Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
te sach » toc sach
ma hoi » mai hoi, ma hoa, me hoi
xuc va » duc va, tuc va, luc va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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 (te sach)) ky nang ((ma hoi) OR (xa hoi)). hieu van cam xuc va dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) ky nang ((ma hoi) OR (xa hoi)). hieu van cam xuc va dan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (te sach)) ky nang ((ma hoi) OR (xa hoi)). hieu van cam xuc va dan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) ky nang ((ma hoi) OR (xa hoi)). hieu van cam xuc va dan vi cua tre*.