Perhaps you should try some spelling variations:
luc tieng » hoc tieng
duc tien » duc thien, thuc tien, doc tieng
hanh may » hanh ma, hanh mau, hanh ngay
sach ky » sac ky, sach y, sach ty
duc tre » duoc tren
tu sach » thu sach, su sach, te sach
cac tac » cac toc, cac bac, cac dac
hieu ve » hieu va, hieu van
dang ma » dang mau, dang mam, dang mat
ky dang » ky nang, ky danh
xa hanh » xa thanh, xa khanh, va hanh
tac xa » tuc xa, tac da
ve cac » va cac, vien cac

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 ky dang ma hoa. hieu ve cac tac xa hanh may ((duc tre) or (((duc tien) OR (luc tieng))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ma hoa. hieu ve cac tac xa hanh may ((duc tre) OR (((duc tien) OR (luc tieng)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ma hoa. hieu ve cac tac xa hanh may ((duc tre) or (((duc tien) OR (luc tieng))))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ma hoa. hieu ve cac tac xa hanh may ((duc tre) or (((duc tien) OR (luc tieng))))*.