Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
toc sach » hoc sach, doc sach, thuoc sach
hieu va » lieu va, hieu qua
vai cuu » vai cua
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
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 vai cuu tre~.
• 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 vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang ma hoi. ((hieu ve) OR (hieu va)) cam ((xuc va) or (luc va)) thanh vai cuu tre".
• 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 vai cuu tre*.