Perhaps you should try some spelling variations:
dong hoa » dong hoc, dong co
hieu van » hieu va, thien van, hieu ve
van hanh » van thanh, ban hanh, van anh
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
hanh va » hang va, hanh vi
cuu tre » cua tre, cau tren, cau treo
lam vo » lam co, lam so, lam vu
va cuu » va cau, va chu, va huu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((dong hoa) OR (van xay)) hoi. ((hieu van) OR (lieu va)) lam vo van hanh va cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((dong hoa) or (van xay)) hoi. ((hieu van) OR (lieu va)) lam vo van hanh va cuu tre~".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((dong hoa) or (van xay)) hoi. ((hieu van) OR (lieu va)) lam vo van hanh va cuu tre*.