Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tu sach » thu sach, su sach, te sach
danh va » doanh va, hanh va, anh va
va danh » va dinh, va dan, va hanh
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
ve cac » va cac, vien cac
he va » che va, he van, te va
thiet » thieu

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 y ((nang xa) or (nang ma)) hoi. hieu ve cac he va danh va ((cua triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (nang ma)) hoi. hieu ve cac he va danh va ((cua triet) OR (va thiet)).
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (nang ma)) hoi. hieu ve cac he va danh va ((cua triet) or (va thiet))*.