Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
van hanh » van thanh, ban hanh, van anh
ve triet » va trien, su triet
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
duc van » duc va, duc tan, duc manh
hanh de » hanh ve, hanh kem
y nang » ky nang, ly nang, v nang

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)) pham duc van hanh de 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)) pham duc van hanh de ve triet.
• Adding a wildcard symbol may retrieve word variants: doc sach y nang xa hoi. ((hieu va) or (lieu va)) pham duc van hanh de ve triet*.