Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
lang ha » long ha
va hanh » va thanh, va danh, ban hanh
ha hoi » hoa hoi, ha noi, xa hoi

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 ty lang ha hoi. hieu van nam thuc ((va hanh) or (van hanh)) ((ki su) OR (ky su)) tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty lang ha hoi. hieu van nam thuc ((va hanh) OR (van hanh)) ((ki su) OR (ky su)) tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty lang ha hoi. hieu van nam thuc ((va hanh) or (van hanh)) ((ki su) OR (ky su)) tien".
• Adding a wildcard symbol may retrieve word variants: te sach ty lang ha hoi. hieu van nam thuc ((va hanh) or (van hanh)) ((ki su) OR (ky su)) tien*.