Perhaps you should try some spelling variations:
thanh phai » thanh hai, thanh phan, thanh pham
thu sach » tu sach, thuat sach, thuoc sach
lang mai » lang dai, lang hai, lang man
phai la » phai lam, phan lap, phan lan
cuc ban » cua ban, cac ban, cuu ban
luc ban » duc ban, luc bat, luc van
la tren » loai tren, dua tren, dat tren
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
ky lang » ky nang, ky dang, ky tang
ve cau » ke cau, va cau, le cau
ve cac » va cac, vien cac

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 lang mai hoi. hieu ((ve cau) or (ve cac)) ((luc ban) OR (cuc ban)) thanh phai la tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky lang mai hoi. hieu ((ve cau) OR (ve cac)) ((luc ban) OR (cuc ban)) thanh phai la tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky lang mai hoi. hieu ((ve cau) or (ve cac)) ((luc ban) OR (cuc ban)) thanh phai la tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang mai hoi. hieu ((ve cau) or (ve cac)) ((luc ban) OR (cuc ban)) thanh phai la tren*.