Perhaps you should try some spelling variations:
sach cay » sach cap, sach hay, sach nay
cay mang » cach mang, cay mac, cay cong
te sach » toc sach
may hoi » may thoi, tay hoi, mai hoi
hieu ve » hieu van
hieu va » lieu va, hieu qua
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
xuc va » tuc va, luc va, xac va
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach cay mang may hoi. ((hieu ve) OR (hieu va)) cac ((xuc va) or (duc va)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach cay mang may hoi. ((hieu ve) OR (hieu va)) cac ((xuc va) OR (duc va)) hanh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach cay mang may hoi. ((hieu ve) OR (hieu va)) cac ((xuc va) or (duc va)) hanh va cua tre*".