Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
hanh dai » hanh tai, hanh dao, vanh dai
tra nang » thi nang, kha nang, da nang
te sach » toc sach
hieu va » lieu va, hieu qua
tuc va » thuc va, truc va, duc va
dai va » mai va
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 lenh) or (tra nang)) xa hoi. hieu va cao ((tuc va) OR (tuc xa)) hanh dai va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu lenh) OR (tra nang)) xa hoi. hieu va cao ((tuc va) OR (tuc xa)) hanh dai va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((tu lenh) or (tra nang)) xa hoi. hieu va cao ((tuc va) OR (tuc xa)) hanh dai va trien".
• Adding a wildcard symbol may retrieve word variants: te sach ((tu lenh) or (tra nang)) xa hoi. hieu va cao ((tuc va) OR (tuc xa)) hanh dai va trien*.