Perhaps you should try some spelling variations:
thien bang » khien bang, thien ban, thien dang
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, hoc sach
va dinh » van dinh, va kinh, va tinh
dinh ve » dinh ket, dinh van
cam tuc » cam xuc, cam tu, nam thuc
van cam » van nam, van lam, van cau
bang xa » lang xa, bang va, mang xa
co sach » bo sach, cuon sach, hoc sach
cuu tre » cua tre, cau tren, cau treo
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) OR (co sach)) thien bang xa hoi. hieu van cam tuc va dinh ve ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) thien bang xa hoi. hieu van cam tuc va dinh ve ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (co sach)) thien bang xa hoi. hieu van cam tuc va dinh ve ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (co sach)) thien bang xa hoi. hieu van cam tuc va dinh ve ((dua tren) or (cuu tre))*.