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
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
van cam » van lam, van cau, van dam
bang xa » lang xa, bang va, mang xa
cuu tre » cua tre, cau tren, cau treo
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 xa hoi. hieu ((van cam) OR (van nam)) xuc va dinh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thien bang xa hoi. hieu ((van cam) OR (van nam)) xuc va dinh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thien bang xa hoi. hieu ((van cam) OR (van nam)) xuc va dinh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach thien bang xa hoi. hieu ((van cam) OR (van nam)) xuc va dinh vi ((dua tren) or (cuu tre))*.