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, co sach
cam tuc » cam xuc, cam tu, nam thuc
dinh ve » dinh ket, dinh van
va dinh » van dinh, va kinh, va tinh
van cam » van nam, van lam, van cau
bang xa » lang xa, bang va, mang xa
vu sach » vu bach, su sach, vu khach
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 (vu 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 (vu 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 (vu sach)) thien bang xa hoi. hieu van cam tuc va dinh ve ((dua tren) or (cuu tre))*.