Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
thanh vi » hanh vi, thanh va, thanh ve
hieu va » lieu va, hieu qua
ky tang » ky dang, kho tang, ky trong
va cao » va cac, va co, va dao
luc va » duc va, tuc va
loc va » hoc va
vi cau » va cau, ve cau, di cau
te san » te ban, ke san, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: te san ((ky tang) or (ky nang)) xa hoi. hieu va cao ((luc va) OR (loc va)) thanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te san ((ky tang) OR (ky nang)) xa hoi. hieu va cao ((luc va) OR (loc va)) thanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te san ((ky tang) or (ky nang)) xa hoi. hieu va cao ((luc va) OR (loc va)) thanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: te san ((ky tang) or (ky nang)) xa hoi. hieu va cao ((luc va) OR (loc va)) thanh vi cau tren*.