Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vai » thanh hai, thanh van, thanh tai
hieu van » hieu va, thien van, hieu ve
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
nam dua » nam da, nam cua, nam mua
dua ban » dia ban, cua ban, qua ban
vai dau » va dau, van dau, xvii dau

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 nang ((mai hoi) or (ma hoa)). ((hieu van) or (lieu va)) nam dua ban thanh vai dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((mai hoi) OR (ma hoa)). ((hieu van) OR (lieu va)) nam dua ban thanh vai dau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((mai hoi) or (ma hoa)). ((hieu van) or (lieu va)) nam dua ban thanh vai dau tren*.