Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hang tai » hang va, dung tai
cua tre » cua te, cuu tre, cua triet
va hang » van hang, va nang, va lang
su sach » so sach, vu sach
le hang » le hoang, le thang, le hong
lo hang » ly hang, cho hang, le thang
hieu va » lieu va, hieu qua
cac tu » cac thu, cach tu, cac du

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 ((lo hang) or (le hang)) cau hoi. hieu va cac tu va hang tai ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((lo hang) OR (le hang)) cau hoi. hieu va cac tu va hang tai ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: su sach ((lo hang) or (le hang)) cau hoi. hieu va cac tu va hang tai ((cua tre) or (cau tren))*.