Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
hang dich » hoang dinh, van dich, ban dich
sach hoc » cach hoc, sach hoi, mach hoc
cac cong » cua cong
cong hoc » dong hoc, cong hoa, cong coc
dan hang » ban hang, van hang, dat hang
giao dan » gian dan, giao dat, giao dien
su sach » so sach, vu sach
can hoi » can ho, dan hoi, van hoi
ca giao » cua giao, co giao, va giao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach hoc tap, nghien cac cong hoc dan hang dich ((can hoi) or (cau hoi)) ca giao dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach hoc tap, nghien cac cong hoc dan hang dich ((can hoi) OR (cau hoi)) ca giao dan.
• Adding a wildcard symbol may retrieve word variants: su sach hoc tap, nghien cac cong hoc dan hang dich ((can hoi) or (cau hoi)) ca giao dan*.