Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
toc sach » hoc sach, doc sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
hieu ve » hieu van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
tai cau » tai cac, tai cao
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
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: toc sach ky nang ma hoi. ((hieu ve) or (hieu va)) cam ((xuc va) or (luc va)) thanh tai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ma hoi. ((hieu ve) OR (hieu va)) cam ((xuc va) OR (luc va)) thanh tai cau tren.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ma hoi. ((hieu ve) or (hieu va)) cam ((xuc va) or (luc va)) thanh tai cau tren*.