Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
tinh hai » tinh thai, tinh chat, trinh han
tu sach » thu sach, su sach, te sach
hai cua » thai cua, dai cua, hoi cua
cau tuc » cau truc, cau luc, cau phuc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
cau tu » dau tu, cau truc
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 ve) or (hieu qua)) ((cau tuc) OR (cau tu)) may tinh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang x hoi. ((hieu ve) OR (hieu qua)) ((cau tuc) OR (cau tu)) may tinh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu nang x hoi. ((hieu ve) or (hieu qua)) ((cau tuc) OR (cau tu)) may tinh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang x hoi. ((hieu ve) or (hieu qua)) ((cau tuc) OR (cau tu)) may tinh hai cua tre*.