Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
hoc van » hoc dan, hoc va, hoc vat
cao hoc » co hoc, cho hoc, chat hoc
hieu ve » hieu va, hieu van
ty nang » ty xang, ty hang, ly nang
ve cao » va cao, ve bao, ve cac
va cuu » va cau, va huu
va chu » va che, va cau, va chi

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