Perhaps you should try some spelling variations:
cac tran » cac thanh, cac trung, vach tran
tran van » luan van
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
v nang » va nang, vu nang, van nang
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: su sach ((v nang) or (tran quang)) xa hoi. hieu va cac tran van hanh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (tran quang)) xa hoi. hieu va cac tran van hanh dai va triet.
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) or (tran quang)) xa hoi. hieu va cac tran van hanh dai va triet*.