Perhaps you should try some spelling variations:
tinh xvii » tinh vi, tinh voi
toc sach » hoc sach, doc sach, thuoc sach
dau tren » dau tien, dat tren, dau tieng
sach ky » sac ky, sach y, sach ty
van lam » van nam
van cau » van dau, van hau, van chat
va tinh » may tinh
x hoi » xa hoi, o hoi, 5 hoi

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 ky nang ((x hoi) or (x ho)). hieu ((van lam) or (van cau)) tu va tinh xvii dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ((x hoi) OR (x ho)). hieu ((van lam) OR (van cau)) tu va tinh xvii dau tren.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ((x hoi) or (x ho)). hieu ((van lam) or (van cau)) tu va tinh xvii dau tren*.