Perhaps you should try some spelling variations:
thanh vai » thanh van, thanh tai, thanh oai
thanh hai » thanh phan, thanh hoa, thanh san
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
duc ban » duc tan, duc van, duc man
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
ve cam » ve cham, ve cac, va cam
ma hoi » mai hoi, xa hoi, ma hoa

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 ky nang ma hoi. hieu ve cam ((duc ban) OR (dua ban)) ((thanh vai) or (thanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu ve cam ((duc ban) OR (dua ban)) ((thanh vai) OR (thanh hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. hieu ve cam ((duc ban) OR (dua ban)) ((thanh vai) or (thanh hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu ve cam ((duc ban) OR (dua ban)) ((thanh vai) or (thanh hai)) cua tre*.