Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
va triet » va trien, ve triet, cua triet
hanh vai » hanh vi, hanh va, hanh tai
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
hieu ha » hieu hoa, hieu va, hieu ca
sach ky » sac ky, sach y, sach ty
hoa hoi » khoa hoi, hoa doi, hoc hoi
ky lang » ky nang, ky dang, ky tang
thiet » thieu

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 lang ((hoa hoi) OR (hoa hoc)). hieu ha nam thuc dan hanh vai ((va triet) OR (va thiet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang ((hoa hoi) OR (hoa hoc)). hieu ha nam thuc dan hanh vai ((va triet) or (va thiet))~".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang ((hoa hoi) OR (hoa hoc)). hieu ha nam thuc dan hanh vai ((va triet) or (va thiet))*.