Perhaps you should try some spelling variations:
te sach » toc sach
hieu va » lieu va, hieu qua
cam duc » cam xuc, pham duc, nam duoc
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
hanh de » hanh ve, hanh kem
cau tre » cau tren, cau treo, cau tra
y nang » ly nang, v nang, may nang
de cau » ke cau, le cau, ve 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 ((y nang) or (ky nang)) xa hoi. hieu va ((cam duc) OR (cao duc)) va hanh de cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y nang) OR (ky nang)) xa hoi. hieu va ((cam duc) OR (cao duc)) va hanh de cau tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y nang) or (ky nang)) xa hoi. hieu va ((cam duc) OR (cao duc)) va hanh de cau tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((y nang) or (ky nang)) xa hoi. hieu va ((cam duc) OR (cao duc)) va hanh de cau tre*.