Perhaps you should try some spelling variations:
thi hanh » thi thanh
hanh cao » hanh cac, hanh cat, hanh cad
sach thi » sach thu, sach tai, sach thieu
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
va cham » va chat, va tham
ve chat » va chat, van chat
hanh va » hang va, hanh vi
va cau » van cau, va cac, va dau
cau tu » dau tu, cau truc
loc va » luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thi hanh cao hoi. hieu ((va cham) or (ve chat)) ((loc va) or (hoc va)) hanh va cau tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi hanh cao hoi. hieu ((va cham) OR (ve chat)) ((loc va) OR (hoc va)) hanh va cau tu.
• Adding a wildcard symbol may retrieve word variants: tu sach thi hanh cao hoi. hieu ((va cham) or (ve chat)) ((loc va) or (hoc va)) hanh va cau tu*.