Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
va hanh » van hanh, va thanh, va danh
hoc duc » hoc duoc, hoc nuoc, hoc thuc
hac duc » ha duc, thach duc, pham duc
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty hang, ly nang
tai su » tai so, tai tu, lai su

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) or (ty xang)) xa hoi. hieu van ((hac duc) OR (hoc duc)) va hanh tai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty xang)) xa hoi. hieu van ((hac duc) OR (hoc duc)) va hanh tai su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) or (ty xang)) xa hoi. hieu van ((hac duc) OR (hoc duc)) va hanh tai su triet*".