Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
xang dai » xang dau, lang dai, hoang dai
dao dinh » do dinh, dao minh, dao tinh
dinh cau » dinh chau, dinh cuu, dinh cu
cau tren » cu tren, dau tren, ca tren
dai hoi » dai hoc, dai hai, dai moi
qua cac » cua cac
cac thi » cac thoi, cau thi, can thi
thi ca » thi cam, thi cua, thi cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ty xang dai hoi. hieu qua cac thi ca dao dinh cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ty xang dai hoi. hieu qua cac thi ca dao dinh cau tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ty xang dai hoi. hieu qua cac thi ca dao dinh cau tren*.