Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
vat hanh » vat thanh, van hanh, va hanh
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
hanh ve » hanh vi, hanh va, hanh kem
hieu ve » hieu va
hoc hoi » hoc khoi, hoc hoa, hoc noi
sac ky » cac ky, sai ky
ho hoi » hoa hoi, hoi hoi, co hoi
ve cua » le cua, de cua, te cua
su sac » su sach, su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky nang ((ho hoi) or (hoc hoi)). ((hieu ve) OR (hieu van)) nam thuc vat hanh ve cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang ((ho hoi) OR (hoc hoi)). ((hieu ve) OR (hieu van)) nam thuc vat hanh ve cua viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang ((ho hoi) or (hoc hoi)). ((hieu ve) OR (hieu van)) nam thuc vat hanh ve cua viet*".