Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
hieu cua » hieu qua, dieu cua, bieu cua
thanh va » thanh van, thanh ha, thanh ve
thuoc va » thuc va, thuoc ma, thuong va
tu sach » thu sach, su sach, te sach
hanh va » hang va, hanh vi
cua nam » cua tam, cua ngan, cua nhan
sach ly » sach y, sach lo, sach ty
ly tang » le tang, ly hang, ly vang
cuu tre » cua tre, cau tren, cau treo
ma hoi » mai hoi, xa hoi, me hoi

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 ly tang ((ma hoi) OR (ma hoa)). hieu cua nam thuoc va ((thanh va) or (hanh va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly tang ((ma hoi) OR (ma hoa)). hieu cua nam thuoc va ((thanh va) OR (hanh va)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly tang ((ma hoi) OR (ma hoa)). hieu cua nam thuoc va ((thanh va) or (hanh va)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ly tang ((ma hoi) OR (ma hoa)). hieu cua nam thuoc va ((thanh va) or (hanh va)) cuu tre*.