Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
phan cung » phan cong, phan ung, phan xuong
van thanh » ban thanh, van tuan
thanh tao » thanh thao, thanh tai, thanh tay
cac cong » cua cong
cong hoc » dong hoc, cong hoa, cong coc
hoc phan » hoc dan, hoc pho
cung hoc » chung hoc, dung hoc, vung hoc
tu mach » tu cach, tu manh, tu sach
tu hach » tu hanh, tu cach, tu sach
hoi van » hoi va, hoi dan, hai van
ma hoi » mai hoi, xa hoi, ma hoa

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) or (tu hach)) hoc tap, nghien cac cong hoc phan cung hoc ma hoi van thanh tao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu mach) OR (tu hach)) hoc tap, nghien cac cong hoc phan cung hoc ma hoi van thanh tao.
• Adding a wildcard symbol may retrieve word variants: ((tu mach) or (tu hach)) hoc tap, nghien cac cong hoc phan cung hoc ma hoi van thanh tao*.