Perhaps you should try some spelling variations:
dang than » dang thanh, sang than, dang tran
thien van » thi van
thu sach » thuat sach, thuoc sach, thu hoach
su triet » su viet, su tien
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
ve triet » va trien
va dang » van dang, va nang, va lang
tu sach » su sach, te sach, tu cach
van cac » van hac, van cau, van bac
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (tu sach)) ky nang x hoi. thien van cac nuoc va dang than ((su triet) OR (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ky nang x hoi. thien van cac nuoc va dang than ((su triet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ky nang x hoi. thien van cac nuoc va dang than ((su triet) OR (ve triet))".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ky nang x hoi. thien van cac nuoc va dang than ((su triet) OR (ve triet))*.