Perhaps you should try some spelling variations:
dau triet » cau triet, dau tien, su triet
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
nam duoc » nam thuoc, da duoc, dat duoc
ky lang » ky nang, ky dang, ky tang
lang ha » long ha
nam duc » pham duc, nam buoc, nam duoi
hanh va » hang va, hanh vi
va dau » va dao
tu sac » tu sach, tu cac, tu san
ha hoi » hoa hoi, ha noi, xa hoi
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky lang ha hoi. hieu van ((((nam duc) or (nam thuc))) or (nam duoc)) van hanh va dau triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky lang ha hoi. hieu van ((((nam duc) OR (nam thuc))) OR (nam duoc)) van hanh va dau triet.
• Adding a wildcard symbol may retrieve word variants: tu sac ky lang ha hoi. hieu van ((((nam duc) or (nam thuc))) or (nam duoc)) van hanh va dau triet*.