Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cuu tre » cua tre, cau treo
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
hieu va » lieu va, hieu qua
hac tuc » thac toc, thai tuc
va hac » van hac, va khac, va cac
tuc va » thuc va, truc va, tuc xa
tu san » thu san, tu ban, tu can
tu sac » tu sach, tu cac, tu bac
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: ((tu sac) OR (tu san)) ky nang x hoi. hieu va hac tuc va danh vi ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sac) OR (tu san)) ky nang x hoi. hieu va hac tuc va danh vi ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sac) OR (tu san)) ky nang x hoi. hieu va hac tuc va danh vi ((cuu tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: ((tu sac) OR (tu san)) ky nang x hoi. hieu va hac tuc va danh vi ((cuu tre) or (cau tren))*.