Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va tham » van tham, va cham, va thanh
danh vi » hanh vi, dinh vi, danh di
su viet » so viet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi
soc va » loc va, doc va, goc va
vi su » va su, ve su, ki su

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 y nang ((ma hoi) or (ma hoa)). lieu va tham ((soc va) OR (hoc va)) danh vi su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((ma hoi) OR (ma hoa)). lieu va tham ((soc va) OR (hoc va)) danh vi su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((ma hoi) or (ma hoa)). lieu va tham ((soc va) OR (hoc va)) danh vi su viet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((ma hoi) or (ma hoa)). lieu va tham ((soc va) OR (hoc va)) danh vi su viet*.