Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
cuu tre » cau tren, cau treo
luc ban » duc ban, cuc ban, luc bat
nam luc » nang luc, nhan luc, nam thuc
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
tang ma » mang may, tang van
tang xa » trang xa, lang xa, tang ha
cua tre » cua te, cua triet, dua tren

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 ((tang xa) or (tang ma)) hoi. hieu van nam luc ban thanh vi ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((tang xa) OR (tang ma)) hoi. hieu van nam luc ban thanh vi ((cuu tre) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((tang xa) or (tang ma)) hoi. hieu van nam luc ban thanh vi ((cuu tre) or (cua tre))*.