Perhaps you should try some spelling variations:
hanh thuoc » thanh phuoc, hanh phuc, dang thuoc
thuoc cua » thuc cua, thuoc cuc, thuoc luan
thi hang » thi hanh, thi nang, thi hong
tu sach » thu sach, te sach, tu cach
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
tuc va » truc va, tuc xa, duc va
hang o » hang do, hang o2, hoang o
va cau » van cau, va cac, va dau
o hoi » co hoi, o hoc, o hai

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) or (su sach)) thi hang o hoi. hieu va cau ((tuc va) OR (thuc va)) hanh thuoc cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) thi hang o hoi. hieu va cau ((tuc va) OR (thuc va)) hanh thuoc cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) thi hang o hoi. hieu va cau ((tuc va) OR (thuc va)) hanh thuoc cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) thi hang o hoi. hieu va cau ((tuc va) OR (thuc va)) hanh thuoc cua tre*.