Perhaps you should try some spelling variations:
ve triet » va trien
su triet » su viet, su tien
vanh dai » van dai, vanh tai, lanh dao
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
va vanh » va van, va danh, va hanh
tu sach » thu sach, su sach, te sach
van dau » van dao, phan dau
ty nang » ky nang, ty xang, ty hang
dau tuc » dau tu, dao tuc, cau truc
tuc va » thuc va, truc va, tuc xa

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 ty nang ((ma hoa) or (xa hoi)). hieu van dau tuc va vanh dai ((su triet) OR (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((ma hoa) OR (xa hoi)). hieu van dau tuc va vanh dai ((su triet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((ma hoa) or (xa hoi)). hieu van dau tuc va vanh dai ((su triet) OR (ve triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((ma hoa) or (xa hoi)). hieu van dau tuc va vanh dai ((su triet) OR (ve triet))*.