Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
te sach » toc sach
su sach » so sach, vu sach
hieu va » lieu va
cam duc » cam xuc, cao duc, pham duc
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
vi cau » va cau, ve cau, di cau
x hoi » xa hoi, o hoi, x ho

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) or (su sach)) ky nang x hoi. ((hieu va) OR (hieu qua)) cam duc va danh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (su sach)) ky nang x hoi. ((hieu va) OR (hieu qua)) cam duc va danh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (su sach)) ky nang x hoi. ((hieu va) OR (hieu qua)) cam duc va danh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (su sach)) ky nang x hoi. ((hieu va) OR (hieu qua)) cam duc va danh vi cau tren*.