Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
cua tuc » cua duc, cua tu, cua thuoc
ty lang » tay lang, ty xang, tu lang
ty hang » ly hang, ty xang, thi hang
hieu ve » hieu van
tuc van » thuc van, truc van, tuc va
hieu va » lieu va, hieu qua
vi cua » vai cua, di cua
cua te » cua tu

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