Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
thanh vai » thanh hai, thanh van, thanh oai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
dac ban » cac ban, dac san, duc ban
bac dac » bac dai, ban dac, bac dan
van bac » van ban, van bao, van hac
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (su sach)) y nang x hoi. hieu van bac dac ban ((thanh vai) or (thanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang x hoi. hieu van bac dac ban ((thanh vai) OR (thanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang x hoi. hieu van bac dac ban ((thanh vai) or (thanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang x hoi. hieu van bac dac ban ((thanh vai) or (thanh tai)) cua tre*.