Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
so sach » so sanh, bo sach, co sach
thu xac » thau xay
sach ky » sac ky, sach y, sach ty
so viet » hoc viet
nang xa » lang xa, nang ma, mang xa
thu xa » thu ha, thu xe, thu ba
tai so » tai sao, dai so, tai co
van ca » van cau, van cua, dan ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky ((nang xa) or (nang x)) hoi. hieu van ca ((thu xa) OR (thu xac)) hanh tai so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((nang xa) OR (nang x)) hoi. hieu van ca ((thu xa) OR (thu xac)) hanh tai so viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((nang xa) or (nang x)) hoi. hieu van ca ((thu xa) OR (thu xac)) hanh tai so viet".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang xa) or (nang x)) hoi. hieu van ca ((thu xa) OR (thu xac)) hanh tai so viet*.