Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hai truc » dai truc, hai trac, hang truc
van hanh » van thanh, ban hanh, van anh
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
van hai » van ha, van chat, van phan
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) OR (sac ky)) nang xa hoi. hieu van hai truc ((va hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang xa hoi. hieu van hai truc ((va hanh) OR (van hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sac ky)) nang xa hoi. hieu van hai truc ((va hanh) or (van hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sac ky)) nang xa hoi. hieu van hai truc ((va hanh) or (van hanh)) vi cua tre*.