Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
su sach » so sach, vu sach
danh vi » hanh vi, dinh vi, danh di
mai hoi » mai khoi, dai hoi, lai hoi
truc va » thuc va, thuc vat, trung va
qua ca » qua cac, qua cua, qua cai
sach 7 » sach y, sach 2
ma hoi » xa hoi, ma hoa, me hoi
7 tang » 6 tang
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 tang ((ma hoi) OR (mai 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 tang ((ma hoi) OR (mai 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 tang ((ma hoi) OR (mai hoi)). hieu qua ca ((truc va) or (thuc day)) danh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach 7 tang ((ma hoi) OR (mai hoi)). hieu qua ca ((truc va) or (thuc day)) danh vi va thiet*.