Perhaps you should try some spelling variations:
tu tieng » luc tieng, tu tuong, tu trong
ve triet » va trien, su triet
nam thuc » nam thuoc, am thuc, nam thu
lang hoa » hang hoa, lang ha, nang hoa
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu he » hieu ve, hiem he, hieu le
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
ky lang » ky nang, ky dang, ky tang
su sach » so sach, vu sach
he nam » ha nam, nghe nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky lang hoa hoi. hieu he nam thuc va hanh ve ((ve triet) or (tu tieng))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang hoa hoi. hieu he nam thuc va hanh ve ((ve triet) OR (tu tieng)).
• Adding a wildcard symbol may retrieve word variants: su sach ky lang hoa hoi. hieu he nam thuc va hanh ve ((ve triet) or (tu tieng))*.