Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
doi cua » dai cua, hoi cua
thuc va » thuc vat, thuc day
sang ma » tang ma, nang ma, sang tao
hieu le » hieu ve, hieu he, hieu ly
ky sang » ky nang, ky dang, ky tang
le nam » ly nam, he nam, le na
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa
do cua » co cua, de cua, dong cua
su sac » su sach, su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky sang ma hoi. hieu le nam ((thuc va) OR (thuc dan)) hanh ((do cua) or (doi cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky sang ma hoi. hieu le nam ((thuc va) OR (thuc dan)) hanh ((do cua) OR (doi cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky sang ma hoi. hieu le nam ((thuc va) OR (thuc dan)) hanh ((do cua) or (doi cua)) viet".
• Adding a wildcard symbol may retrieve word variants: su sac ky sang ma hoi. hieu le nam ((thuc va) OR (thuc dan)) hanh ((do cua) or (doi cua)) viet*.