Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
van hanh » van thanh, ban hanh, van anh
tang hoi » tang ho, tang loi, tan hoi
tuc van » thuc van, truc van, tuc va
cam tuc » cam xuc, cam tu, nam thuc
hieu va » lieu va
hoi hoi » hoi hoc, hoc hoi, hoi doi
sac ky » cac ky
vi cua » vai cua, di cua

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 ((sac ky) OR (sai ky)) tang hoi hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh vi cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sac ky) or (sai ky)) tang hoi hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sai ky)) tang hoi hoi. ((hieu va) OR (hieu qua)) cam tuc van hanh vi cua viet*.