Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
cua tre » cuu tre, cua triet, dua tren
va lanh » va lang, va danh, va hanh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
va nam » van nam, ha nam, va nay
cua te » cua tu
o lai » o lao
o hai » co hai, so hai, _ hai

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: su sach ky nang ((o hai) OR (o lai)). hieu va nam thuc va lanh dao ((cua tre) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((o hai) or (o lai)). hieu va nam thuc va lanh dao ((cua tre) OR (cua te))~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((o hai) or (o lai)). hieu va nam thuc va lanh dao ((cua tre) OR (cua te))*.