Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
nang doc » nang luc
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
doc hoc » duoc hoc, toc hoc, duc hoc
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
san cau » van cau, ban cau, can cau
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. hieu ve cham ((xac va) or (luc va)) thanh san cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang doc hoc. hieu ve cham ((xac va) OR (luc va)) thanh san cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang doc hoc. hieu ve cham ((xac va) or (luc va)) thanh san cau tren*.