Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
hoc khanh » hoc nhanh, hoc thanh, hoc hanh
khanh hoa » thanh hoa, hang hoa
sach hoi » sach doi, sach moi, hoach hoi
hang tai » hang va, dung tai
va hang » van hang, va nang, va lang
mo hoc » mon hoc, co hoc
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach hoi) or (cach thoi)) tap, nghien cuu mo hoc khanh hoa hoc xa hoi va hang tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach hoi) OR (cach thoi)) tap, nghien cuu mo hoc khanh hoa hoc xa hoi va hang tai.
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoi) or (cach thoi)) tap, nghien cuu mo hoc khanh hoa hoc xa hoi va hang tai*.