Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh oai
thanh tai » thanh hai, thanh toan, doanh tai
so sach » so sanh, bo sach, co sach
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
sach ty » sach y, sach tu, sach thu
hieu va » lieu va
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet

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