Perhaps you should try some spelling variations:
sach hoc » cach hoc, sach hoi, mach hoc
cuu tong » cuu cong, cuu tinh, huu tung
tong hoc » tuong hoc, thong hoc, trong hoc
dan hoat » van hoa, dan hoc, danh hoa
hoat hoc » hoa hoc, hoat ho, khoa hoc
van nhan » van phan, van thanh, danh nhan
nhan dan » phan dau, gian dan, nhan tai
so sach » so sanh, bo sach, co sach
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach hoc tap, nghien cuu tong hoc dan hoat hoc ((ma hoi) or (mai hoi)) van nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach hoc tap, nghien cuu tong hoc dan hoat hoc ((ma hoi) OR (mai hoi)) van nhan dan.
• Adding a wildcard symbol may retrieve word variants: so sach hoc tap, nghien cuu tong hoc dan hoat hoc ((ma hoi) or (mai hoi)) van nhan dan*.