Perhaps you should try some spelling variations:
thien van » thi van
ban thanh » ban hanh, ban hang
hieu van » hieu va, lieu va, hieu ve
te sach » toc sach
lang xa » lang ha, dang xay, lang van
tham so » ham so, tham do, than so
y lang » o lang, _ lang, tay lang
so ban » sao ban, so bang, co ban
vi dau » va dau, bi dau, ve dau
vi dai » si dai, li dai, vien dai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y lang xa hoi. ((hieu van) or (thien van)) tham so ban thanh ((vi dau) OR (vi dai)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y lang xa hoi. ((hieu van) OR (thien van)) tham so ban thanh ((vi dau) OR (vi dai)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y lang xa hoi. ((hieu van) or (thien van)) tham so ban thanh ((vi dau) OR (vi dai)) tren".
• Adding a wildcard symbol may retrieve word variants: te sach y lang xa hoi. ((hieu van) or (thien van)) tham so ban thanh ((vi dau) OR (vi dai)) tren*.