Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
ban hanh » ban hang
chat xuc » chat huu, cam xuc, chao xu
hieu van » hieu va, thien van, lieu va
van chat » cao chat
mai hoi » mai khoi, dai hoi, lai hoi
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 7 tang
ma hoi » xa hoi, ma hoa, me hoi

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

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