Perhaps you should try some spelling variations:
chat truc » cau truc, chat xuc
hieu quan » lieu quan, thien quan, lien quan
cua triet » cua viet, su triet, va triet
thu san » thuy san, thu ban, phu san
truc va » thuc va, thuc vat, trung va
dan dai » dat dai, can dai, dan dat
cua tre » cua te, cuu tre, dua tren
san ky » sang ky, van ky, dan ky
va dan » ca dan, va dao, va dau
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu san ky nang x hoi. ((hieu quan) or (hieu qua)) chat truc va dan dai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu san ky nang x hoi. ((hieu quan) OR (hieu qua)) chat truc va dan dai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu san ky nang x hoi. ((hieu quan) or (hieu qua)) chat truc va dan dai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: thu san ky nang x hoi. ((hieu quan) or (hieu qua)) chat truc va dan dai ((cua tre) OR (cua triet))*.