Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
vai cua » dai cua, hai cua, lai cua
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
ve nham » ve nha, ve cham
ky sang » ky nang, ky dang, ky tang
dan ky » van ky
ma hoi » mai hoi, ma hoa, me hoi
va dan » ca dan, va dao, va dau
di cua » dai cua, doi cua, de cua
tu dan » tuc dan, tu ban, cu dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu dan ky sang ((ma hoi) or (xa hoi)). hieu ve nham thuc va dan ((di cua) or (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu dan ky sang ((ma hoi) OR (xa hoi)). hieu ve nham thuc va dan ((di cua) OR (vai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu dan ky sang ((ma hoi) or (xa hoi)). hieu ve nham thuc va dan ((di cua) or (vai cua)) tre*.