Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
tinh doi » trinh doc, trinh do, tinh hoc
doi cua » dai cua, hoi cua
xa tinh » va tinh, ha tinh, ca tinh
cau tuc » cau truc, cau tu, cau luc
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
ty hang » ly hang, ty xang, thi hang
ty lang » tay lang, ty xang, tu lang

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ty lang) OR (ty hang)) xa hoi. ((hieu ve) OR (hieu va)) cau tuc xa tinh doi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ty lang) OR (ty hang)) xa hoi. ((hieu ve) or (hieu va)) cau tuc xa tinh doi cua tre~".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ty lang) OR (ty hang)) xa hoi. ((hieu ve) or (hieu va)) cau tuc xa tinh doi cua tre*.