Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
danh dai » danh dau, danh di, danh sai
van nham » van nam, van nhan, van tham
hieu van » hieu va, thien van, lieu va
hoc sach » hoc sinh, hoc cac, hoc anh
va triet » va thiet, va trien, ve triet
nang xa » nang x, lang xa, nang ma
thue va » thuc va, thuyet va, thuc vat
thu va » thuc va, tu va, thu ha
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (hoc sach)) ky nang xa hoi. hieu van nham ((thu va) or (thue va)) danh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky nang xa hoi. hieu van nham ((thu va) OR (thue va)) danh dai va triet.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ky nang xa hoi. hieu van nham ((thu va) or (thue va)) danh dai va triet*.