Perhaps you should try some spelling variations:
dieu cua » dieu tra
lap thuc » tap thuc, luan thuc, phap thuc
tu sach » thu sach, su sach, te sach
va tinh » may tinh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
sach 2 » sach y
va lap » va dap
ma hoi » xa hoi, ma hoa, me hoi
de cua » le cua, te cua
2 nang » v nang

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 2 nang ((ma hoi) or (mai hoi)). hieu va lap thuc va tinh ((de cua) OR (dieu cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach 2 nang ((ma hoi) OR (mai hoi)). hieu va lap thuc va tinh ((de cua) OR (dieu cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach 2 nang ((ma hoi) or (mai hoi)). hieu va lap thuc va tinh ((de cua) OR (dieu cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach 2 nang ((ma hoi) or (mai hoi)). hieu va lap thuc va tinh ((de cua) OR (dieu cua)) tre*.