Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
thuc day » thuc vat
dang hai » dang khai, hang hai, dung hai
cua viet » ca viet, cua vat, cua dieu
tu sach » thu sach, su sach, te sach
nang co » nang cao, nang doc, nang noi
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
co loi » co hoi
va lam » van lam, va lap

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang co loi. hieu va lam ((thuc dan) OR (thuc day)) dang hai ((cua viet) OR (hoa viet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang co loi. hieu va lam ((thuc dan) or (thuc day)) dang hai ((cua viet) OR (hoa viet))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang co loi. hieu va lam ((thuc dan) or (thuc day)) dang hai ((cua viet) OR (hoa viet))*.