Perhaps you should try some spelling variations:
thuc thanh » thuoc thanh, thuc hanh, phuc thanh
khach hoc » khanh hoa, cach hoc, mach hoc
cong thuc » cong tac
thanh hoa » thanh pho
vu khach » vu khanh, vu khac, vay khach
cuu cong » cua cong, thu cong, cac cong
tran van » luan van
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: vu khach hoc tap, nghien cuu cong thuc thanh hoa hoc xa hoi va ((tran van) or (pham van))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach hoc tap, nghien cuu cong thuc thanh hoa hoc xa hoi va ((tran van) OR (pham van)).
• Adding a wildcard symbol may retrieve word variants: vu khach hoc tap, nghien cuu cong thuc thanh hoa hoc xa hoi va ((tran van) or (pham van))*.