Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach thu » sach thue, sach thieu, sach tham
thu lang » thu hang, thu bang, phu lang
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
ha hoi » ha noi, xa hoi, va hoi

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: su sach thu lang ((ha hoi) OR (hoa hoi)). hieu va pham duc va hanh vi ((cua tre) OR (cau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu lang ((ha hoi) OR (hoa hoi)). hieu va pham duc va hanh vi ((cua tre) or (cau tren))~".
• Adding a wildcard symbol may retrieve word variants: su sach thu lang ((ha hoi) OR (hoa hoi)). hieu va pham duc va hanh vi ((cua tre) or (cau tren))*.