Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cao truc » cau truc, vao truc, cao thuoc
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
va triet » va thiet, va trien, ve triet
hieu va » lieu va, hieu qua
tu nang » tru nang, tu nong, tu lang
va cao » va cac, va co, va dao
dai va » mai va

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

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