Perhaps you should try some spelling variations:
thanh hoa » thanh pho
thanh hai » thanh phan, thanh san
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
cam dua » ca dua, cay dua, chay dua
dua ban » dia ban, cua ban, qua ban
cuc tre » duc tre, cua tre, cuu tre
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang

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