Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
xuc van » duc van, luc van, xuc ban
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
ky sang » ky nang, ky dang, ky tang
ma hoi » mai hoi, ma hoa, me hoi
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: ((tu sach) or (thuoc sach)) ky sang ((ma hoi) OR (xa hoi)). hieu van cam xuc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) ky sang ((ma hoi) OR (xa hoi)). hieu van cam xuc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) ky sang ((ma hoi) OR (xa hoi)). hieu van cam xuc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) ky sang ((ma hoi) OR (xa hoi)). hieu van cam xuc van hanh vi cua tre*.