Perhaps you should try some spelling variations:
nam thuoc » nam thu, nha thuoc, cay thuoc
hoc viet » hoc hien
mai viet » thi viet
hieu van » hieu va, thien van, lieu va
nam thuc » am thuc, nam thu, nam tu
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
ma hoi » mai hoi, xa hoi, ma hoa

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 sang ma hoi. hieu van ((nam thuc) or (nam thuoc)) va hanh vi ((mai viet) or (hoc viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ma hoi. hieu van ((nam thuc) OR (nam thuoc)) va hanh vi ((mai viet) OR (hoc viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ma hoi. hieu van ((nam thuc) or (nam thuoc)) va hanh vi ((mai viet) or (hoc viet))*.