Perhaps you should try some spelling variations:
tay quang » tac quang, tai quang, tao quang
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cac tu » cac thu, cach tu, cac du
vi cau » va cau, di cau, viet cau
ve cau » ke cau, va cau, ve cac

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 ((tay quang) or (ky nang)) xa hoi. hieu va cac tu va hanh ((vi cau) OR (ve cau)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tay quang) OR (ky nang)) xa hoi. hieu va cac tu va hanh ((vi cau) OR (ve cau)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tay quang) or (ky nang)) xa hoi. hieu va cac tu va hanh ((vi cau) OR (ve cau)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tay quang) or (ky nang)) xa hoi. hieu va cac tu va hanh ((vi cau) OR (ve cau)) triet*.