Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
cao hoc » co hoc, cho hoc, chat hoc
cao hoi » cau hoi, co hoi, tao hoi
ty nang » ky nang, ty xang, ty hang
va cham » va chat, va tham
va dan » ca dan, va dao, va dau
hoi su » hoi suc, khoi su, thoi su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang ((cao hoi) or (cao hoc)). hieu va cham soc ((van hanh) or (va dan)) hoi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((cao hoi) OR (cao hoc)). hieu va cham soc ((van hanh) OR (va dan)) hoi su triet.
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((cao hoi) or (cao hoc)). hieu va cham soc ((van hanh) or (va dan)) hoi su triet*.