Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
hieu van » hieu va, thien van, lieu va
hanh vu » hanh va, hanh tu, hanh ve
cac tuc » cac toc, cac tu, cac tac
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
co sach » bo sach, cuon sach, hoc sach
van cac » van hac, van cau, van bac
ma hoi » mai hoi, xa hoi, ma hoa
tuc va » thuc va, truc va, tuc xa
y nang » ky nang, ly nang, v nang

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 (co sach)) y nang ma hoi. hieu van cac tuc va ((hanh vu) OR (hanh vi)) va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) y nang ma hoi. hieu van cac tuc va ((hanh vu) OR (hanh vi)) va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (co sach)) y nang ma hoi. hieu van cac tuc va ((hanh vu) OR (hanh vi)) va trien".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) y nang ma hoi. hieu van cac tuc va ((hanh vu) OR (hanh vi)) va trien*.