Perhaps you should try some spelling variations:
qua cham » qua hai, qua cac, va cham
thanh vi » hanh vi, thanh va, thanh ve
cuu thuc » cuu tac
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
xac va » tac va, ac va, bac va
vi cuu » vi luu, vinh cuu

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 lang xa hoi. hieu qua cham ((xac va) or (duc va)) thanh vi cuu thuc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang xa hoi. hieu qua cham ((xac va) OR (duc va)) thanh vi cuu thuc.
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang xa hoi. hieu qua cham ((xac va) or (duc va)) thanh vi cuu thuc*.