Perhaps you should try some spelling variations:
chet duoc » che duoc, cho duoc, che quoc
duoc van » duoc va, duc van, duoc ban
van hanh » van thanh, ban hanh, van anh
va trien » va truyen, va tuyen, va tieng
va triet » ve triet, cua triet, va viet
hanh lam » thanh lap, hanh kem, hanh va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
va chet » va chiet, va che, va chat
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang xa hoi. hieu va chet duoc van hanh lam ((va triet) or (((va trien) OR (va thiet))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang xa hoi. hieu va chet duoc van hanh lam ((va triet) OR (((va trien) OR (va thiet)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang xa hoi. hieu va chet duoc van hanh lam ((va triet) or (((va trien) OR (va thiet))))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. hieu va chet duoc van hanh lam ((va triet) or (((va trien) OR (va thiet))))*.