Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
duoc hoc » quoc hoi
cau tren » cu tren, dau tren, ca tren
doc hoc » toc hoc, duc hoc, hoc hoc
sach ky » sac ky, sach y, sach ty
vu cham » va cham, vu kham, tu cham
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
ve cham » va cham, ve chat, ve chim
xuc va » duc va, tuc va, luc va
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: thu sach ky nang ((doc hoc) OR (duoc hoc)). hieu ((ve cham) or (vu cham)) xuc va hanh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((doc hoc) OR (duoc hoc)). hieu ((ve cham) OR (vu cham)) xuc va hanh va cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((doc hoc) OR (duoc hoc)). hieu ((ve cham) or (vu cham)) xuc va hanh va cau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((doc hoc) OR (duoc hoc)). hieu ((ve cham) or (vu cham)) xuc va hanh va cau tren*.