Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
sach nay » sach hay, sach vay, sach nang
sach cay » sach cap, sach hay, sach vay
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cac dac » cac dan, cac dai, cac bac
van cac » van hac, van cau, van bac
tao hoi » tao khoi, tao boi, thao hoc
tay hoi » tay ho, tay thai
dac va » duc va, day va, dat va
cua te » cua tu

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 cay) OR (sach nay)) mang ((tay hoi) or (tao hoi)). hieu van cac dac va hanh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach cay) OR (sach nay)) mang ((tay hoi) OR (tao hoi)). hieu van cac dac va hanh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach cay) OR (sach nay)) mang ((tay hoi) or (tao hoi)). hieu van cac dac va hanh vai cua te".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach cay) OR (sach nay)) mang ((tay hoi) or (tao hoi)). hieu van cac dac va hanh vai cua te*.