Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
qua cac » cua cac
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
danh co » danh cho, doanh co, anh co
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo

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 ((le hoi) or (ma hoa)). hieu qua cac thuc va danh co ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((le hoi) OR (ma hoa)). hieu qua cac thuc va danh co ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((le hoi) or (ma hoa)). hieu qua cac thuc va danh co ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((le hoi) or (ma hoa)). hieu qua cac thuc va danh co ((cua tre) OR (cuu tre))*.