Perhaps you should try some spelling variations:
chong dich » luong dich, hang dich
phan chong » phan cong, phan hong, phap chong
nghien cac » nghiep cach, nghien cuu, nghiep cay
gian dan » gian lang
sach hoc » cach hoc, mach hoc, sach duoc
dich can » dich han, dich ran, lich can
hoc phan » hoc dan, hoc pho
cong hoc » dong hoc, cong hoa, cong coc
cac cong » cua cong
sach hoi » sach doi, sach moi, cach thoi
can hoi » cau hoi, can ho, dan hoi
ca gian » ca giang, ca giao, va gian
hoi ca » hoi cua, hoi cac, hoi cau

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) OR (sach hoi)) tap, nghien cac cong hoc phan chong dich can hoi ca gian dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach hoc) OR (sach hoi)) tap, nghien cac cong hoc phan chong dich can hoi ca gian dan".
• Adding a wildcard symbol may retrieve word variants: su ((sach hoc) OR (sach hoi)) tap, nghien cac cong hoc phan chong dich can hoi ca gian dan*.