Perhaps you should try some spelling variations:
duc danh » duc anh, duc manh, duc dan
duc hanh » duc thanh, duc anh, du hanh
dua tren » dung tren
nhan tai » hang tai, van tai, toan tai
tu sach » thu sach, su sach, te sach
sach ly » sach y, sach lo, sach ty
hieu ve » hieu va, hieu van
ly nang » ky nang, ly hang, ly vang
ve cao » va cao, ve bao, ve cac
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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 ly nang x hoi. hieu ve cao ((duc danh) OR (duc hanh)) nhan tai ((dua tren) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly nang x hoi. hieu ve cao ((duc danh) OR (duc hanh)) nhan tai ((dua tren) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly nang x hoi. hieu ve cao ((duc danh) OR (duc hanh)) nhan tai ((dua tren) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach ly nang x hoi. hieu ve cao ((duc danh) OR (duc hanh)) nhan tai ((dua tren) or (cua te))*.