Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hang vai » hang tai, hang hai, hang vi
doc sach » hoc sach, toc sach, nuoc sach
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
cac lo » cac lop, cac co, cac bo
lo van » le van, vo van, so van
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky ((nang xa) OR (nang x)) hoi. hieu ve cac lo van ((hang vai) or (hang va)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky ((nang xa) OR (nang x)) hoi. hieu ve cac lo van ((hang vai) OR (hang va)) cua triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky ((nang xa) OR (nang x)) hoi. hieu ve cac lo van ((hang vai) or (hang va)) cua triet*".