Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
lam thuc » lam thuoc, nam thuc, dam thuc
tinh vai » tinh va, tinh hai, tinh bai
te sach » toc sach
mai hoi » mai khoi, dai hoi, lai hoi
va tinh » may tinh
y nang » ky nang, ly nang, v nang
ma hoi » xa hoi, ma hoa, me hoi
vai va » mai va, dai va, hai va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang ((ma hoi) or (mai hoi)). hieu van ((lam thuc) OR (am thuc)) va tinh vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((ma hoi) OR (mai hoi)). hieu van ((lam thuc) OR (am thuc)) va tinh vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((ma hoi) or (mai hoi)). hieu van ((lam thuc) OR (am thuc)) va tinh vai va thiet".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((ma hoi) or (mai hoi)). hieu van ((lam thuc) OR (am thuc)) va tinh vai va thiet*.