Perhaps you should try some spelling variations:
sang dai » sang tai, lang dai, sang mai
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
hieu ve » hieu va, hieu van
co viet » so viet, o viet, hoc viet
cam tu » cam thu, nam tu, dam tu
thuc » thu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky sang dai hoc. hieu ve ((am thuc) or (cam tu)) van hanh vi ((co viet) or (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang dai hoc. hieu ve ((am thuc) OR (cam tu)) van hanh vi ((co viet) OR (hoa viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky sang dai hoc. hieu ve ((am thuc) or (cam tu)) van hanh vi ((co viet) or (hoa viet))*.