Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
vu sach » vu bach, su sach, vu khach
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
ve cac » vien cac
x hoi » xa hoi, o hoi, x ho

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

• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach thu nang x hoi. hieu ((ve cac) OR (va cac)) duc va hanh vi ((cua tre) OR (cuu tre))~.
• Adding a wildcard symbol may retrieve word variants: vu sach thu nang x hoi. hieu ((ve cac) or (va cac)) duc va hanh vi ((cua tre) or (cuu tre))*.