Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
thai cua » than cua, tri cua, dai cua
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va
cao suc » cao su, cao duc
suc van » su van, duc van, luc van
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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: te sach ky nang o hai. ((hieu ve) OR (hieu van)) cao suc van hanh ((thai cua) OR (tai cuc)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang o hai. ((hieu ve) or (hieu van)) cao suc van hanh ((thai cua) OR (tai cuc)) tre~".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang o hai. ((hieu ve) or (hieu van)) cao suc van hanh ((thai cua) OR (tai cuc)) tre*.