Perhaps you should try some spelling variations:
hieu cao » chieu cao, hieu cac, hieu ca
thuc van » thuc vat, thuc dan, thuc hanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
thuc va » thuc vat, thuc dan, thuc day
duc van » duc va, duc tan, duc manh
hanh va » hang va, hanh vi
va va » va van, va vua, va vai
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 cao hoi. hieu cao chat ((((thuc van) OR (thuc va))) or (duc van)) hanh va va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. hieu cao chat ((((thuc van) OR (thuc va))) OR (duc van)) hanh va va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang cao hoi. hieu cao chat ((((thuc van) OR (thuc va))) or (duc van)) hanh va va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. hieu cao chat ((((thuc van) OR (thuc va))) or (duc van)) hanh va va thiet*.