Perhaps you should try some spelling variations:
sang dai » sang tai, lang dai, sang mai
ky sang » ky nang, ky dang, ky tang
dai hoi » dai hoc, dai hai, dai moi
hieu su » hieu sau, tieu su, hieu so
su phap » su pham, su phat, cu phap
phap xu » phap tu, phap thu, phap ngu
va hanh » van hanh, va thanh, va danh
tu sai » tu bai, tu cai, tu lai
tu san » thu san, tu ban, tu can
vi cua » vai cua, di cua
cua te » cua tu
xu va » xu van, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sai) OR (tu san)) ky sang dai hoi. hieu su phap xu va hanh vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sai) OR (tu san)) ky sang dai hoi. hieu su phap xu va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sai) OR (tu san)) ky sang dai hoi. hieu su phap xu va hanh vi cua te*.