Perhaps you should try some spelling variations:
thuc day » thuc vat
thuc dan » thuc hanh, hoc dan, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu le » hieu ve, hieu he, hieu ly
thuc va » thuc vat
le nam » ly nam, he nam, le na
vi va » vi van, vai va, vu 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: tu sach ky nang xa hoi. hieu le nam ((((thuc va) OR (thuc day))) or (thuc dan)) hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu le nam ((((thuc va) OR (thuc day))) OR (thuc dan)) hanh vi va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu le nam ((((thuc va) OR (thuc day))) or (thuc dan)) hanh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu le nam ((((thuc va) OR (thuc day))) or (thuc dan)) hanh vi va thiet*.