Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
tu sach » thu sach, su sach, te sach
hieu va » lieu va
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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 thu nang x hoi. ((hieu va) or (hieu qua)) pham duc va danh vi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang x hoi. ((hieu va) OR (hieu qua)) pham duc va danh vi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu nang x hoi. ((hieu va) or (hieu qua)) pham duc va danh vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang x hoi. ((hieu va) or (hieu qua)) pham duc va danh vi ((cua tre) OR (cua te))*.