Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hieu van » hieu va, thien van, lieu va
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
cac bac » cac bai, cac ban, cac cach
cac tac » cac toc, cac dac, cac tai
su sach » vu sach
nang ma » tang ma, sang ma, nang cao
so sach » so sanh, bo sach, co sach
ma hoi » mai hoi, xa hoi, ma hoa
y nang » ky nang, ly nang, v nang
di va » dai va, di vao, doi 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) or (so sach)) y nang ma hoi. hieu van ((cac tac) or (cac bac)) va hanh di va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) y nang ma hoi. hieu van ((cac tac) OR (cac bac)) va hanh di va triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) y nang ma hoi. hieu van ((cac tac) or (cac bac)) va hanh di va triet*.