Perhaps you should try some spelling variations:
vien dai » hien dai
hang tai » dung tai
vien cac » vien bach, vien da, gian cac
duc ban » duc tan, duc van, dua ban
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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 v nang xa hoi. hieu ((vien cac) OR (vien dai)) duc ban ((hang tai) or (hang va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v nang xa hoi. hieu ((vien cac) OR (vien dai)) duc ban ((hang tai) OR (hang va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach v nang xa hoi. hieu ((vien cac) OR (vien dai)) duc ban ((hang tai) or (hang va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach v nang xa hoi. hieu ((vien cac) OR (vien dai)) duc ban ((hang tai) or (hang va)) cua tre*.