Perhaps you should try some spelling variations:
ban trinh » ban tinh, dan trinh, van trinh
cau tren » cu tren, dau tren, ca tren
trinh va » trinh van, trinh vat, trinh ve
cam cua » ca cua, nam cua, cau cua
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, tu cach
tay hoi » tao hoi, tay thai
ky dang » ky nang, ky danh
te sach » toc sach
tay ho » tay co, tay o, tay khao
ve cam » ve cham, ve cac, va cam
va cau » van cau, va cac, va dau

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 dang ((tay hoi) OR (tay ho)). hieu ve cam cua ban trinh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky dang ((tay hoi) OR (tay ho)). hieu ve cam cua ban trinh va cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky dang ((tay hoi) OR (tay ho)). hieu ve cam cua ban trinh va cau tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky dang ((tay hoi) OR (tay ho)). hieu ve cam cua ban trinh va cau tren*.