Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
thu sach » tu sach, thuat sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
toc hoc » toan hoc, duoc hoc
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
doc hoc » duoc hoc, duc hoc, hoc hoc
van cau » van dau, van hau, van chat
ve cham » va cham, ve chat, vu cham
xac va » tac va, ac va, bac va
luc va » duc va, tuc va, loc va

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 nang ((doc hoc) OR (toc hoc)). hieu ve cham ((xac va) or (luc va)) thanh van cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((doc hoc) OR (toc hoc)). hieu ve cham ((xac va) OR (luc va)) thanh van cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((doc hoc) OR (toc hoc)). hieu ve cham ((xac va) or (luc va)) thanh van cau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((doc hoc) OR (toc hoc)). hieu ve cham ((xac va) or (luc va)) thanh van cau tren*.