Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sach vu » sach tu, sach uu, sach xu
hanh ky » hanh kem
xuc van » duc van, luc van, vuc van
hieu va » lieu va, hieu qua
so viet » hoc viet
sach va » sach xa, sach ha, sach dao
ma hoi » mai hoi, ma hoa, me hoi
va cam » va cham, va cac, va cao
ky so » ly so, ky su, ka so

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 vu) or (sach va)) nang ((ma hoi) OR (xa hoi)). hieu va cam xuc van hanh ky so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach vu) OR (sach va)) nang ((ma hoi) OR (xa hoi)). hieu va cam xuc van hanh ky so viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach vu) or (sach va)) nang ((ma hoi) OR (xa hoi)). hieu va cam xuc van hanh ky so viet".
• Adding a wildcard symbol may retrieve word variants: te ((sach vu) or (sach va)) nang ((ma hoi) OR (xa hoi)). hieu va cam xuc van hanh ky so viet*.