Perhaps you should try some spelling variations:
thien van » thi van
hac quoc » han quoc, hoc quoc, cac quoc
thu sach » thuat sach, thuoc sach, thu hoach
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
van hac » van hoc, van ha, van hai
tu sach » su sach, te sach, tu cach
hai su » hai vu, lai su, tai su
hai so » dai so, tai so, thai son
gia » giao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thu sach)) ty nang xa hoi. thien van hac quoc gia thanh ((hai su) OR (hai so)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty nang xa hoi. thien van hac quoc gia thanh ((hai su) OR (hai so)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ty nang xa hoi. thien van hac quoc gia thanh ((hai su) OR (hai so)) triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty nang xa hoi. thien van hac quoc gia thanh ((hai su) OR (hai so)) triet*.