Perhaps you should try some spelling variations:
xa thanh » va thanh, ha thanh, ta thanh
vien cac » vien bach, vien dai, vien da
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
ve cac » va cac
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai
vi su » ve su, ki su, oi 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 ky nang o hoi. hieu ((ve cac) or (vien cac)) tuc xa thanh ((vi su) OR (va su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. hieu ((ve cac) OR (vien cac)) tuc xa thanh ((vi su) OR (va su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoi. hieu ((ve cac) or (vien cac)) tuc xa thanh ((vi su) OR (va su)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoi. hieu ((ve cac) or (vien cac)) tuc xa thanh ((vi su) OR (va su)) triet*.