Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » duc va, tuc va, luc 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 (thuoc sach)) ky nang ma hoi. ((hieu ve) or (hieu va)) cam xuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) ky nang ma hoi. ((hieu ve) OR (hieu va)) cam xuc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuoc sach)) ky nang ma hoi. ((hieu ve) or (hieu va)) cam xuc va hanh vi cua tre*.