Perhaps you should try some spelling variations:
cach khoan » cac khoan, cach hoan, bach khoa
khoan phai » khong phai, khoa phau, khoan hoi
phai thong » phap thong, phai tuong, phan thong
hoc thong » hoc thuong, hoc trong, hoc hong
hang khoa » dung khoa
hoach hoi » hoc hoi, hoach ha, sach hoi
thu hang » thi hang, thuc hanh, thu huong
khoa hoc » hoa hoc
tue cach » tu cach, thuc cach, ve cach
hoc cac » hoc cao
cac thu » cach thuc, cac thoi
thu thu » thu thuy, thue thu, thu thuc
hoi tue » hoi tu, choi tre, hoi tiep

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( hoc cac thu thu hang khoa hoc thong ) or ( thu hoach hoi tue cach khoan phai thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( hoc cac thu thu hang khoa hoc thong ) OR ( thu hoach hoi tue cach khoan phai thong )).
• Adding a wildcard symbol may retrieve word variants: (( hoc cac thu thu hang khoa hoc thong ) or ( thu hoach hoi tue cach khoan phai thong ))*.