Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
va triet » va thiet, va trien, ve triet
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
sai ky » sac ky
va cau » van cau, va cac, va dau
dai va » mai 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 y) or (sai ky)) ((nang xa) OR (lang xa)) hoi. hieu va cau truc va hanh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sai ky)) ((nang xa) OR (lang xa)) hoi. hieu va cau truc va hanh dai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach y) or (sai ky)) ((nang xa) OR (lang xa)) hoi. hieu va cau truc va hanh dai va triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sai ky)) ((nang xa) OR (lang xa)) hoi. hieu va cau truc va hanh dai va triet*.