Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
sach tru » sach truc, sach thu, sach tu
va hanh » van hanh, va thanh, va danh
va lanh » va lang, va danh, va anh
hac xuc » chat xuc
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
hai va » hai van, thai va, hoi va
va hac » van hac, va khac, va cac

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 tru ((nang xa) OR (lang xa)) hoi. hieu va hac xuc ((va lanh) or (va hanh)) hai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tru ((nang xa) OR (lang xa)) hoi. hieu va hac xuc ((va lanh) OR (va hanh)) hai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tru ((nang xa) OR (lang xa)) hoi. hieu va hac xuc ((va lanh) or (va hanh)) hai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach tru ((nang xa) OR (lang xa)) hoi. hieu va hac xuc ((va lanh) or (va hanh)) hai va triet*.