Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va dinh » van dinh, va kinh, va tinh
va hanh » van hanh, va thanh, va danh
cac luc » cau luc, coc luc, cac nuoc
so viet » hoc viet
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
ty nang » ky nang, ty hang, ly nang
hoi so » hoi co, hoi o, hai so
ve cac » va cac, vien cac

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) OR (ty xang)) cao hoi. hieu ve cac luc ((va hanh) or (va dinh)) hoi so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ty xang)) cao hoi. hieu ve cac luc ((va hanh) OR (va dinh)) hoi so viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ty xang)) cao hoi. hieu ve cac luc ((va hanh) or (va dinh)) hoi so viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) OR (ty xang)) cao hoi. hieu ve cac luc ((va hanh) or (va dinh)) hoi so viet*.