Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
sach ky » sach y, sach ty, sach kem
thuc va » thuc vat, thuc dan, thuc day
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
tuc va » truc va, tuc xa, duc va
sac ky » cac ky, sai ky
vai va » mai va, dai va, hai va
thiet » thieu

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) or (sac ky)) nang cao hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang cao hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) nang cao hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vai va thiet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang cao hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vai va thiet*.