Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac
va cam » va cham, va cac, va cao

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 y nang ma hoa. hieu ((ve cac) or (va cam)) thuc va hanh vi ((cua tre) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoa. hieu ((ve cac) OR (va cam)) thuc va hanh vi ((cua tre) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ma hoa. hieu ((ve cac) or (va cam)) thuc va hanh vi ((cua tre) or (va triet))*.