Perhaps you should try some spelling variations:
hoc khanh » hoc nhanh, hoc thanh, hoc hanh
khanh hoa » thanh hoa, hang hoa
sach hoc » cach hoc, mach hoc, sach duoc
sach hoi » sach doi, sach moi, cach thoi
cuu dong » cuu cong, cuu tong, cuu long
dong hoc » dong co, dong luc
va nhan » van nhan, ca nhan, va phan
nhan va » nhan tai, nhan dan, nhan tao
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 ((sach hoc) OR (sach hoi)) tap, nghien cuu dong hoc khanh hoa hoc ma hoi va nhan va~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach hoc) OR (sach hoi)) tap, nghien cuu dong hoc khanh hoa hoc ma hoi va nhan va".
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoc) OR (sach hoi)) tap, nghien cuu dong hoc khanh hoa hoc ma hoi va nhan va*.