Perhaps you should try some spelling variations:
thien van » thi van
ban thanh » ban hanh, ban hang
dau tren » dau tien, dat tren, dau tieng
hieu van » hieu va, lieu va, hieu ve
thanh vi » hanh vi, thanh va, thanh ve
tham so » ham so, tham do, than so
sach ky » sach y, sach ty, sach kem
lang xa » lang ha, dang xay, lang van
sac ky » cac ky, sai ky
so ban » sao ban, so bang, co ban
vi dau » vi dai, va dau, bi dau

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