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