Perhaps you should try some spelling variations:
cach viet » bach viet, danh viet, bac viet
nam thuc » nam thuoc, am thuc, nam thu
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va dinh » van dinh, va kinh, vu dinh
va tinh » may tinh
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san ky nang xa hoi. hieu va nam thuc ((va dinh) or (va tinh)) tai ((cach viet) OR (anh viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky nang xa hoi. hieu va nam thuc ((va dinh) OR (va tinh)) tai ((cach viet) OR (anh viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san ky nang xa hoi. hieu va nam thuc ((va dinh) or (va tinh)) tai ((cach viet) OR (anh viet))".
• Adding a wildcard symbol may retrieve word variants: tu san ky nang xa hoi. hieu va nam thuc ((va dinh) or (va tinh)) tai ((cach viet) OR (anh viet))*.