Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
van thanh » ban thanh, van tuan
van cham » van chat, van tham, va cham
hieu van » hieu va, thien van, lieu va
cham hoc » cham soc, chat hoc, cham hoi
lang ha » long ha
hoc van » hoc dan, hoc va, hoc vat
cua tu » cua tuc, cua cu, cua te
sac ky » sai ky
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sac ky) OR (cac ky)) lang ha noi. hieu van cham hoc van thanh vai ((cua tu) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (cac ky)) lang ha noi. hieu van cham hoc van thanh vai ((cua tu) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sac ky) OR (cac ky)) lang ha noi. hieu van cham hoc van thanh vai ((cua tu) or (cua su))".
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) OR (cac ky)) lang ha noi. hieu van cham hoc van thanh vai ((cua tu) or (cua su))*.