Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, qua ban
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
cay dua » chay dua, cay lua, ca dua
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa

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 ma hoi. ((hieu van) OR (hieu va)) cay dua ban thanh vai ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. ((hieu van) OR (hieu va)) cay dua ban thanh vai ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. ((hieu van) OR (hieu va)) cay dua ban thanh vai ((cuu tre) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. ((hieu van) OR (hieu va)) cay dua ban thanh vai ((cuu tre) or (cua tre))*.