Perhaps you should try some spelling variations:
tru nang » tra nang, tri nang, truc nano
hanh tai » thanh tai, hang tai, han tai
te sach » toc sach
tu nang » tu nong, tu nano, tu lang
hieu va » lieu va, hieu qua
cao tuc » dao tuc, cao duc, cao suc
va hanh » van hanh, va thanh, va danh
va cao » va cac, va co, va dao
tuc va » thuc va, truc va, tuc xa
tai va » thai va, mai va, tri va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((tu nang) or (tru nang)) xa hoi. hieu va cao tuc va hanh tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu nang) OR (tru nang)) xa hoi. hieu va cao tuc va hanh tai va thiet.
• Adding a wildcard symbol may retrieve word variants: te sach ((tu nang) or (tru nang)) xa hoi. hieu va cao tuc va hanh tai va thiet*.