Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lo tuan » le tuan, lo tan, lo xuan
do tuan » do xuan, do quang
anh via » anh va, anh bia, anh viet
via cua » gia cua, gian cua, giau cua
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
x hoi » o hoi, x ho, 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: thuat sach ky nang ((x hoi) or (xa hoi)). hieu ve cac ((lo tuan) OR (do tuan)) anh via cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ((x hoi) OR (xa hoi)). hieu ve cac ((lo tuan) OR (do tuan)) anh via cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ((x hoi) or (xa hoi)). hieu ve cac ((lo tuan) OR (do tuan)) anh via cua tre".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((x hoi) or (xa hoi)). hieu ve cac ((lo tuan) OR (do tuan)) anh via cua tre*.