Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » hieu va, thien van, lieu va
hanh tai » hang tai, han tai, hinh tai
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
so viet » hoc viet
nang xa » lang xa, nang ma, mang xa
ca thu » cac thu, cam thu, ca tru
thu xa » thu xac, thu ha, thu xe
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 ty ((nang xa) or (nang x)) hoi. hieu van ca thu xa ((hanh tai) OR (thanh tai)) so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang xa) OR (nang x)) hoi. hieu van ca thu xa ((hanh tai) OR (thanh tai)) so viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ((nang xa) or (nang x)) hoi. hieu van ca thu xa ((hanh tai) OR (thanh tai)) so viet".
• Adding a wildcard symbol may retrieve word variants: so sach ty ((nang xa) or (nang x)) hoi. hieu van ca thu xa ((hanh tai) OR (thanh tai)) so viet*.