Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hang hai » hoang hai, hang tai, thanh hai
ban hang » ngan hang
hieu va » lieu va, hieu qua
hai cuc » tai cuc, hai cua, thai cua
dua ban » dia ban, cua ban, qua ban
cam dua » ca dua, cay dua, chay dua
cuc tre » duc tre, cua tre, cuu tre
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty hang, ly nang

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 ((ty nang) OR (ty xang)) mai hoi. ((hieu ve) or (hieu va)) cam dua ban hang hai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty nang) OR (ty xang)) mai hoi. ((hieu ve) OR (hieu va)) cam dua ban hang hai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty nang) OR (ty xang)) mai hoi. ((hieu ve) or (hieu va)) cam dua ban hang hai cuc tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty nang) OR (ty xang)) mai hoi. ((hieu ve) or (hieu va)) cam dua ban hang hai cuc tre*.