Perhaps you should try some spelling variations:
thuat bai » thuat bao, thuyet bai, thuat xay
thanh hai » thanh phan, thanh hoa, thanh san
cau tren » cu tren, dau tren, ca tren
nam thuc » nam thuoc, nam thu, nam tu
va thanh » gia thanh, ban thanh, va tinh
hai cau » hai chau, hai chu, hai hau
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
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: ((tu sach) or (thuat bai)) ky nang ma hoi. hieu ve ((nam thuc) OR (am thuc)) va thanh hai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat bai)) ky nang ma hoi. hieu ve ((nam thuc) OR (am thuc)) va thanh hai cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuat bai)) ky nang ma hoi. hieu ve ((nam thuc) OR (am thuc)) va thanh hai cau tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat bai)) ky nang ma hoi. hieu ve ((nam thuc) OR (am thuc)) va thanh hai cau tren*.