Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hanh vai » hanh vi, hanh va, hanh tai
dang mau » dong mau, dang van, dang su
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
mau hoa » cau hoa, ma hoa, mai hoa
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va

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) OR (doc sach)) ky dang mau hoa. ((hieu ve) or (lieu va)) cam xuc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky dang mau hoa. ((hieu ve) OR (lieu va)) cam xuc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky dang mau hoa. ((hieu ve) or (lieu va)) cam xuc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky dang mau hoa. ((hieu ve) or (lieu va)) cam xuc va hanh vai cua tre*.