Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien bang » khien bang, thien ban, thien dang
dua tren » dung tren
su sach » so sach, vu sach
bang va » hang va, ban va, trang va
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
va hoi » xa hoi, va hoc, va hoa
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: su sach thien bang va hoi. hieu ((van lam) or (van nam)) xuc va hanh vi ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thien bang va hoi. hieu ((van lam) OR (van nam)) xuc va hanh vi ((dua tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: su sach thien bang va hoi. hieu ((van lam) or (van nam)) xuc va hanh vi ((dua tren) or (cua tre))*.