Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
ve triet » va trien
dang hoa » dang hoai, dang khoa, dong hoa
su triet » su viet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu he » hieu ve, hiem he, hieu le
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky dang » ky nang, ky danh
su tien » su kien, su hien, tu tieng
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: tu sach ky dang hoa hoi. hieu he nam thuc vat hanh vi ((((su triet) or (ve triet))) or (su tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang hoa hoi. hieu he nam thuc vat hanh vi ((((su triet) OR (ve triet))) OR (su tien)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang hoa hoi. hieu he nam thuc vat hanh vi ((((su triet) or (ve triet))) or (su tien))*.