Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van chat » cao chat
chat hoc » chat hoa, chat thom, cho hoc
hanh dai » hanh tai, hanh dao, vanh dai
cua viet » ca viet, hoa viet, cua vat
tu cach » tu cac
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, va danh

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (((te sach) OR (toc sach)))) ky nang xa hoi. hieu van chat hoc va hanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (((te sach) OR (toc sach)))) ky nang xa hoi. hieu van chat hoc va hanh dai cua viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (((te sach) OR (toc sach)))) ky nang xa hoi. hieu van chat hoc va hanh dai cua viet*".