Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dinh lai » dinh lam, dinh lap, dinh tai
lam duoc » nam duoc, luat duoc, lam thuoc
lai cua » dai cua, hai cua, lai chau
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va dinh » van dinh, va kinh, va tinh
y nang » ky nang, ly nang, v nang
cua su » qua su

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 (toc sach)) y nang xa hoi. hieu va ((lam duoc) or (am thuc)) va dinh lai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang xa hoi. hieu va ((lam duoc) OR (am thuc)) va dinh lai cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang xa hoi. hieu va ((lam duoc) or (am thuc)) va dinh lai cua su".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang xa hoi. hieu va ((lam duoc) or (am thuc)) va dinh lai cua su*.