Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hai cua » thai cua, dai cua, hoi cua
vai cua » dai cua, lai cua, bai cua
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cam tu » cam thu, nam tu, dam tu
tu van » tu va
va cam » va cham, va cac, va cao

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 y ((nang xa) OR (lang xa)) hoi. hieu va cam tu van hanh ((vai cua) or (hai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (lang xa)) hoi. hieu va cam tu van hanh ((vai cua) OR (hai cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) OR (lang xa)) hoi. hieu va cam tu van hanh ((vai cua) or (hai cua)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) OR (lang xa)) hoi. hieu va cam tu van hanh ((vai cua) or (hai cua)) viet*.