Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
hanh cua » manh cua, hang cua, hanh sua
cuu tre » cua tre, cau treo
va hanh » van hanh, va thanh, va danh
cac tuc » cac toc, cac tu, cac tac
tu sach » thu sach, su sach, te sach
hieu va » lieu va
nang ma » tang ma, sang ma, nang cao
tuc va » thuc va, truc va, tuc xa
ma hoi » mai hoi, xa hoi, ma hoa

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 ma hoi. ((hieu va) OR (hieu qua)) cac tuc va hanh cua ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang ma hoi. ((hieu va) OR (hieu qua)) cac tuc va hanh cua ((cuu tre) OR (cau tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu nang ma hoi. ((hieu va) OR (hieu qua)) cac tuc va hanh cua ((cuu tre) or (cau tren))*".