Perhaps you should try some spelling variations:
va thieu » va thiet, va hieu, va tieu
hanh may » hanh ma, hanh mau, hanh ngay
thuc day » thuc dan, thuc vat
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
tuc va » thuc va, truc va, tuc xa
ma hoi » xa hoi, ma hoa, me hoi
may va » may vi, day va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((ma hoi) OR (mai hoi)). lieu va cac ((tuc va) or (thuc day)) hanh may va thieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((ma hoi) OR (mai hoi)). lieu va cac ((tuc va) OR (thuc day)) hanh may va thieu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((ma hoi) OR (mai hoi)). lieu va cac ((tuc va) or (thuc day)) hanh may va thieu".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((ma hoi) OR (mai hoi)). lieu va cac ((tuc va) or (thuc day)) hanh may va thieu*.