Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
dua tren » dung tren
thanh vi » hanh vi, thanh va, thanh ve
su sach » so sach, vu sach
duc ban » duc tan, duc van, dua ban
sach ky » sac ky, sach y, sach ty
van bao » van ban, van dao
van cao » van dao, van hao, van cau
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo

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 ky nang xa hoi. hieu ((van cao) OR (van bao)) duc ban thanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. hieu ((van cao) OR (van bao)) duc ban thanh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. hieu ((van cao) OR (van bao)) duc ban thanh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. hieu ((van cao) OR (van bao)) duc ban thanh vi ((dua tren) or (cuu tre))*.