Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, tao hoi
cao hoc » co hoc, cho hoc, chat hoc
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
xuc va » tuc va, luc va, xac va
vi cau » va cau, ve cau, di cau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ((cao hoi) or (cao hoc)). hieu ve cam ((xuc va) or (duc va)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((cao hoi) OR (cao hoc)). hieu ve cam ((xuc va) OR (duc va)) hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((cao hoi) or (cao hoc)). hieu ve cam ((xuc va) or (duc va)) hanh vi cau tren*.