Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va hanh » va thanh, va danh, ban hanh
ca tren » cau tren, la tren, co tren
cu tren » tu tren, dua tren
nam tu » nam thu, nam thuc
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 ky nang x hoi. hieu van nam tu ((va hanh) or (van hanh)) vi ((ca tren) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu van nam tu ((va hanh) OR (van hanh)) vi ((ca tren) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu van nam tu ((va hanh) or (van hanh)) vi ((ca tren) OR (cu tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu van nam tu ((va hanh) or (van hanh)) vi ((ca tren) OR (cu tren))*.