Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
van chat » cao chat
danh day » danh dau, dan day, doanh dao
va triet » va thiet, va trien, ve triet
tu sach » su sach, te sach, tu cach
soc va » loc va, doc va, goc va
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: ((tu sach) OR (thu sach)) ky nang x hoi. hieu van chat ((soc va) or (hoc va)) danh day va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang x hoi. hieu van chat ((soc va) OR (hoc va)) danh day va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky nang x hoi. hieu van chat ((soc va) or (hoc va)) danh day va triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky nang x hoi. hieu van chat ((soc va) or (hoc va)) danh day va triet*.