Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
qua cai » qua hai, qua cac, qua ca
vai cua » dai cua, hai cua, lai cua
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » tuc va, luc va, xac va
vi cua » di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang ma hoi. hieu qua cai ((xuc va) or (duc va)) thanh ((vi cua) OR (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ma hoi. hieu qua cai ((xuc va) OR (duc va)) thanh ((vi cua) OR (vai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ma hoi. hieu qua cai ((xuc va) or (duc va)) thanh ((vi cua) OR (vai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ma hoi. hieu qua cai ((xuc va) or (duc va)) thanh ((vi cua) OR (vai cua)) tre*.