Perhaps you should try some spelling variations:
khanh khong » khanh phong, khanh thuong, nhanh chong
cuu hoang » luu hoang, cuu hoan, cau hoang
hoang hoa » hang hoa, hoang ha, hoang thoan
hoa khanh » hoa thanh, hoa phan, hoa hinh
khong hoc » khung hoc, thong hoc, khong thuoc
mach hoc » cach hoc, dich hoc, anh hoc
sach doi » sach hoi, sach moi, sach dao
nhan van » nhan dan, nhan va, phan van
va nhan » van nhan, ca nhan, va phan
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 ((mach hoc) or (sach doi)) tap, nghien cuu hoang hoa khanh khong hoc xa hoi va nhan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((mach hoc) OR (sach doi)) tap, nghien cuu hoang hoa khanh khong hoc xa hoi va nhan van.
• Adding a wildcard symbol may retrieve word variants: tu ((mach hoc) or (sach doi)) tap, nghien cuu hoang hoa khanh khong hoc xa hoi va nhan van*.