Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
ve triet » va trien, su triet
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
cam duc » cam xuc, cao duc, nam duoc
va hanh » van hanh, va thanh, va danh
y nang » ky nang, ly nang, v nang
kem ve » ke ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach y nang xa hoi. ((hieu va) or (lieu va)) ((cam duc) OR (pham duc)) va hanh kem ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y nang xa hoi. ((hieu va) OR (lieu va)) ((cam duc) OR (pham duc)) va hanh kem ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach y nang xa hoi. ((hieu va) or (lieu va)) ((cam duc) OR (pham duc)) va hanh kem ve triet".
• Adding a wildcard symbol may retrieve word variants: doc sach y nang xa hoi. ((hieu va) or (lieu va)) ((cam duc) OR (pham duc)) va hanh kem ve triet*.