Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
nang van » dang van, tang van, lang van
hieu van » thien van, lieu va
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
van hoi » van hoa, van hoc, van hoe
hieu va » lieu va, hieu qua
vi hoa » voi hoa, vi hoc, va hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang van hoi. ((((hieu ve) OR (hieu va))) OR (hieu van)) nham thuc day hanh vi hoa viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang van hoi. ((((hieu ve) OR (hieu va))) or (hieu van)) nham thuc day hanh vi hoa viet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang van hoi. ((((hieu ve) OR (hieu va))) or (hieu van)) nham thuc day hanh vi hoa viet*.