Perhaps you should try some spelling variations:
thien van » thi van
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, lieu va, hieu ve
ty hang » ly hang, ty xang, thi hang
mai hoi » mai khoi, dai hoi, lai hoi
ty tang » tay tang, ty xang, ky tang
va dinh » van dinh, va kinh, va tinh
dinh ca » dinh cac, dinh cua, dinh cao
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ty tang) OR (ty hang)) mai hoi. ((hieu van) or (thien van)) cam xuc va dinh ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty tang) OR (ty hang)) mai hoi. ((hieu van) OR (thien van)) cam xuc va dinh ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty tang) OR (ty hang)) mai hoi. ((hieu van) or (thien van)) cam xuc va dinh ca cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty tang) OR (ty hang)) mai hoi. ((hieu van) or (thien van)) cam xuc va dinh ca cua tre*.