Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
chat hoc » chat hoa, chat thom, cho hoc
lang van » dang van, tang van, hoang van
vu sach » vu bach, su sach, vu khach
va hanh » van hanh, va thanh, va danh
vu chat » va chat, ve chat, du chat
hieu vu » hieu va, hieu ve, hieu su
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay
cua tu » cua tuc, cua cu, cua te
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: vu sach ty ((lang xa) or (lang van)) hoi. hieu vu chat hoc va hanh thai ((cua tu) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty ((lang xa) OR (lang van)) hoi. hieu vu chat hoc va hanh thai ((cua tu) OR (cua su)).
• Adding a wildcard symbol may retrieve word variants: vu sach ty ((lang xa) or (lang van)) hoi. hieu vu chat hoc va hanh thai ((cua tu) or (cua su))*.