Perhaps you should try some spelling variations:
thanh tap » thanh lap, thanh tai, thanh tay
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
cua viet » hoa viet, cua vat, cua dieu
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
van bac » van ban, van bao, van hac
ca viet » va viet, co viet, hoa viet
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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 ty nang o hai. hieu van bac duc va thanh tap ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang o hai. hieu van bac duc va thanh tap ((cua viet) OR (ca viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hai. hieu van bac duc va thanh tap ((cua viet) or (ca viet))*.