Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
va triet » va thiet, ve triet, cua triet
hanh dai » hanh tai, hanh dao, vanh dai
cao tuc » dao tuc, cao duc, cao suc
xa hanh » xa thanh, xa khanh, va hanh
te sach » toc sach
hieu va » lieu va, hieu qua
tu nang » tru nang, tu nong, tu nano
va cao » va cac, va co, va dao

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 (truc nano)) xa hoi. hieu va cao tuc xa hanh dai ((va triet) or (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu nang) OR (truc nano)) xa hoi. hieu va cao tuc xa hanh dai ((va triet) OR (va trien)).
• Adding a wildcard symbol may retrieve word variants: te sach ((tu nang) or (truc nano)) xa hoi. hieu va cao tuc xa hanh dai ((va triet) or (va trien))*.