Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, thanh san
tu sach » thu sach, su sach, tu cach
cam dua » ca dua, cay dua, chay dua
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
te sach » toc sach
va cam » va cham, va cac, va cao

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