Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
danh vi » hanh vi, dinh vi, danh di
tang ma » mang may, tang van
truc va » thuc va, thuc vat, trung va
qua ca » qua cac, qua cua, qua cai
sach 7 » sach y
ma hoi » mai hoi, xa hoi, ma hoa
sach 2 » sach y
vi va » vi van, vai va, vu va
thiet » thieu

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 7) OR (sach 2)) tang ma hoi. hieu qua ca ((truc va) or (thuc day)) danh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach 7) OR (sach 2)) tang ma hoi. hieu qua ca ((truc va) OR (thuc day)) danh vi va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach 7) OR (sach 2)) tang ma hoi. hieu qua ca ((truc va) or (thuc day)) danh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: su ((sach 7) OR (sach 2)) tang ma hoi. hieu qua ca ((truc va) or (thuc day)) danh vi va thiet*.