Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van chat » cao chat
chat soc » cham soc, chat hoc, chat doc
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
han tai » hang tai, nhan tai, toan tai
van tai » von tai, van tuan
soc va » hoc va, loc va, doc va
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: tu sach ky nang xa hoi. hieu van chat soc va ((han tai) or (van tai)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu van chat soc va ((han tai) OR (van tai)) va thiet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu van chat soc va ((han tai) or (van tai)) va thiet*.