Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
su triet » su viet, su tien, ve triet
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
va danh » va dinh, va dan, va hanh
danh ki » danh di, danh kien, danh gia
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac
ki su » ky su

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 ve cac duc va danh ki su triet~.
• Adding a wildcard symbol may retrieve word variants: doc sach y nang xa hoi. hieu ve cac duc va danh ki su triet*.