Perhaps you should try some spelling variations:
thuat sach » thuat lanh
thuat san » thuat toan, thuat song, thuat lanh
va hang » van hang, va nang, va lang
cao duc » dao duc, cao suc, giao duc
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va cua » va chua, via cua, ca cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuat sach) or (thuat san)) y nang xa hoi. ((hieu ve) OR (hieu va)) cao duc va hang va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuat sach) OR (thuat san)) y nang xa hoi. ((hieu ve) OR (hieu va)) cao duc va hang va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuat sach) or (thuat san)) y nang xa hoi. ((hieu ve) OR (hieu va)) cao duc va hang va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuat sach) or (thuat san)) y nang xa hoi. ((hieu ve) OR (hieu va)) cao duc va hang va cua tre*.