Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cay phoi » cap phoi, tay hoi, cay cho
hanh hoi » hanh thoi, hanh noi, hanh hoa
vat hanh » vat thanh, van hanh, va hanh
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
van hoc » van hoa
xay hoi » xa hoi, tay hoi, gay thoi
ky dang » ky nang, ky danh
hoi cua » hoi chuc
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky dang ((xay hoi) OR (cay phoi)). hieu ((van cau) or (van hoc)) thuc vat hanh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky dang ((xay hoi) OR (cay phoi)). hieu ((van cau) OR (van hoc)) thuc vat hanh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky dang ((xay hoi) OR (cay phoi)). hieu ((van cau) or (van hoc)) thuc vat hanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky dang ((xay hoi) OR (cay phoi)). hieu ((van cau) or (van hoc)) thuc vat hanh hoi cua tre*.